diff --git a/apps/web/src/agent-chat-launch.test.ts b/apps/web/src/agent-chat-launch.test.ts
deleted file mode 100644
index 4ed0d39c3..000000000
--- a/apps/web/src/agent-chat-launch.test.ts
+++ /dev/null
@@ -1,78 +0,0 @@
-import { afterEach, describe, expect, test } from "bun:test";
-
-import { launchAgentChat } from "./agent-chat-launch";
-
-describe("launchAgentChat", () => {
-  const realFetch = globalThis.fetch;
-
-  afterEach(() => {
-    globalThis.fetch = realFetch;
-  });
-
-  type RecordedCall = { readonly path: string; readonly init?: RequestInit };
-
-  function stubFetch(respond: (path: string) => Response): RecordedCall[] {
-    const calls: RecordedCall[] = [];
-    globalThis.fetch = ((input: RequestInfo | URL, init?: RequestInit) => {
-      const path = typeof input === "string" ? input : new URL(String(input)).pathname;
-      calls.push(init === undefined ? { path } : { path, init });
-      return Promise.resolve(respond(path));
-    }) as typeof fetch;
-    return calls;
-  }
-
-  const json = (body: unknown, status = 200) =>
-    new Response(JSON.stringify(body), {
-      status,
-      headers: { "content-type": "application/json" },
-    });
-
-  test("creates a chat for the given definitionId with no reuseExisting flag, and navigates to it", async () => {
-    const navigated: string[] = [];
-    const calls = stubFetch((path) => {
-      if (path.endsWith("/chat/workbenches")) {
-        return json({
-          id: "chan-1",
-          title: "Echo",
-          kind: "chat",
-          pinned: false,
-          participants: [],
-        });
-      }
-      throw new Error(`unexpected fetch: ${path}`);
-    });
-
-    await launchAgentChat("tnt_1", "wfd_echo", (to) => navigated.push(to));
-
-    const call = calls.find((c) => c.path.endsWith("/chat/workbenches"));
-    expect(JSON.parse(String(call?.init?.body))).toEqual({
-      kind: "chat",
-      definitionId: "wfd_echo",
-    });
-    expect(navigated).toEqual(["/w/chan-1"]);
-  });
-
-  test("passes an explicit name through when given one", async () => {
-    const calls = stubFetch((path) => {
-      if (path.endsWith("/chat/workbenches")) {
-        return json({
-          id: "chan-2",
-          title: "New Workbench",
-          kind: "chat",
-          pinned: false,
-          participants: [],
-        });
-      }
-      throw new Error(`unexpected fetch: ${path}`);
-    });
-
-    await launchAgentChat("tnt_1", "wfd_assistant", () => {}, "New Workbench");
-
-    const call = calls.find((c) => c.path.endsWith("/chat/workbenches"));
-    expect(JSON.parse(String(call?.init?.body))).toEqual({
-      kind: "chat",
-      definitionId: "wfd_assistant",
-      name: "New Workbench",
-    });
-  });
-});
diff --git a/apps/web/src/agent-chat-launch.ts b/apps/web/src/agent-chat-launch.ts
deleted file mode 100644
index ba5772fd2..000000000
--- a/apps/web/src/agent-chat-launch.ts
+++ /dev/null
@@ -1,26 +0,0 @@
-// The one path from "an agent's definitionId" to "the person is in a
-// fresh chat with it" — the same `POST /workbenches` call this app's every
-// create path uses. `CreateAgentPanel`'s Settings → Agents entry point
-// calls this on success so an explicitly-defined new agent never ends
-// nowhere, and `instant-agent-create.ts` — THE one creation verb —
-// calls it against the account's default setup template.
-// Always creates — never the `reuseExisting` land-hop path,
-// which is `default-agent-workbench.ts`'s own call, not this one.
-
-import { createWorkbench } from "@/chat";
-
-import { workbenchPath } from "./workbench-path";
-
-export async function launchAgentChat(
-  tenantId: string,
-  definitionId: string,
-  navigate: (to: string) => void,
-  name?: string,
-): Promise<void> {
-  const workbench = await createWorkbench(tenantId, {
-    kind: "chat",
-    definitionId,
-    ...(name !== undefined ? { name } : {}),
-  });
-  navigate(workbenchPath(workbench.id));
-}
diff --git a/apps/web/src/agent-dm-launch.test.ts b/apps/web/src/agent-dm-launch.test.ts
deleted file mode 100644
index d5dff8bfc..000000000
--- a/apps/web/src/agent-dm-launch.test.ts
+++ /dev/null
@@ -1,72 +0,0 @@
-import { afterEach, describe, expect, test } from "bun:test";
-
-import { openAgentDmChat } from "./agent-dm-launch";
-
-describe("openAgentDmChat", () => {
-  const realFetch = globalThis.fetch;
-
-  afterEach(() => {
-    globalThis.fetch = realFetch;
-  });
-
-  type RecordedCall = { readonly path: string; readonly init?: RequestInit };
-
-  function stubFetch(respond: (path: string) => Response): RecordedCall[] {
-    const calls: RecordedCall[] = [];
-    globalThis.fetch = ((input: RequestInfo | URL, init?: RequestInit) => {
-      const path = typeof input === "string" ? input : new URL(String(input)).pathname;
-      calls.push(init === undefined ? { path } : { path, init });
-      return Promise.resolve(respond(path));
-    }) as typeof fetch;
-    return calls;
-  }
-
-  const json = (body: unknown, status = 200) =>
-    new Response(JSON.stringify(body), {
-      status,
-      headers: { "content-type": "application/json" },
-    });
-
-  test("opens the agent's DM with reuseExisting and navigates to it", async () => {
-    const navigated: string[] = [];
-    const calls = stubFetch((path) => {
-      if (path.endsWith("/chat/workbenches")) {
-        return json({
-          id: "chan-dm-1",
-          title: "Outreach",
-          kind: "chat",
-          pinned: false,
-          participants: [],
-        });
-      }
-      throw new Error(`unexpected fetch: ${path}`);
-    });
-
-    await openAgentDmChat("tnt_root", "wfd_outreach", (to) => navigated.push(to));
-
-    const call = calls.find((c) => c.path.endsWith("/chat/workbenches"));
-    expect(call?.path).toBe("/api/tenants/tnt_root/chat/workbenches");
-    expect(JSON.parse(String(call?.init?.body))).toEqual({
-      kind: "chat",
-      definitionId: "wfd_outreach",
-      reuseExisting: true,
-    });
-    expect(navigated).toEqual(["/w/chan-dm-1"]);
-  });
-
-  test("mints in the definition's owning tenant, not necessarily the caller's own", async () => {
-    const calls = stubFetch(() =>
-      json({
-        id: "chan-dm-2",
-        title: "Outreach",
-        kind: "chat",
-        pinned: false,
-        participants: [],
-      }),
-    );
-
-    await openAgentDmChat("tnt_ancestor", "wfd_outreach", () => {});
-
-    expect(calls[0]?.path).toBe("/api/tenants/tnt_ancestor/chat/workbenches");
-  });
-});
diff --git a/apps/web/src/agent-dm-launch.ts b/apps/web/src/agent-dm-launch.ts
deleted file mode 100644
index 3f5c89258..000000000
--- a/apps/web/src/agent-dm-launch.ts
+++ /dev/null
@@ -1,21 +0,0 @@
-// The one path from an agent definition's id to "the person is in their
-// direct chat with it" — the sidebar's agent rows are the one
-// caller. Mirrors `agent-chat-launch.ts`'s shape exactly, but through
-// `openAgentDm` (`kind: "chat"`, `reuseExisting: true`) rather than
-// `createWorkbench` directly: the first click mints the DM, every later
-// click finds the same workbench by `chat/definitionId`
-// (`findExistingAgentChat` in `packages/chat/src/routes.ts`) instead of
-// spawning a new one each time.
-
-import { openAgentDm } from "@/chat";
-
-import { workbenchPath } from "./workbench-path";
-
-export async function openAgentDmChat(
-  tenantId: string,
-  definitionId: string,
-  navigate: (to: string) => void,
-): Promise<void> {
-  const workbench = await openAgentDm(tenantId, definitionId);
-  navigate(workbenchPath(workbench.id));
-}
diff --git a/apps/web/src/agents-api.ts b/apps/web/src/agents-api.ts
index 263bc3eb4..7f48c1759 100644
--- a/apps/web/src/agents-api.ts
+++ b/apps/web/src/agents-api.ts
@@ -289,3 +289,18 @@ export function useDeployAgentMutation(tenantId: string) {
     },
   });
 }
+
+// The guided capability-add surface: only what this tenant actually has.
+const CapabilityInventoryWire = type({
+  toolPackages: type({ name: "string" }).array(),
+  skills: type({ name: "string" }).array(),
+  models: type({ canonicalName: "string" }).array(),
+});
+export type CapabilityInventory = typeof CapabilityInventoryWire.infer;
+
+export function listCapabilityInventory(tenantId: string): Promise<CapabilityInventory> {
+  return getJSON(
+    `/api/tenants/${tenantId}/agent-definitions/capabilities/inventory`,
+    CapabilityInventoryWire,
+  );
+}
diff --git a/apps/web/src/app.css b/apps/web/src/app.css
index d921efe24..1a5001d9e 100644
--- a/apps/web/src/app.css
+++ b/apps/web/src/app.css
@@ -3860,3 +3860,58 @@ button.mission-control-jump-row:hover {
 .chat-composer > textarea {
   width: 100%;
 }
+
+/* A workbench room: timeline in the stage, sub-thread replies beside it. */
+.room-layout {
+  display: flex;
+  min-height: 0;
+  flex: 1;
+}
+.room-participants {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.5rem;
+  margin: 0 0 1rem;
+  padding: 0;
+  list-style: none;
+  font-size: 0.82rem;
+  color: var(--muted-foreground);
+}
+.room-participants > li {
+  display: flex;
+  align-items: center;
+  gap: 0.35rem;
+}
+.room-replies-link {
+  display: block;
+  margin-top: 0.35rem;
+  padding: 0;
+  border: 0;
+  background: none;
+  font-size: 0.78rem;
+  color: var(--muted-foreground);
+  cursor: pointer;
+}
+.room-replies-link:hover {
+  color: var(--foreground);
+}
+.room-subthread {
+  display: flex;
+  flex-direction: column;
+  width: 22rem;
+  min-height: 0;
+  overflow-y: auto;
+  padding: 1rem;
+  border-left: 1px solid var(--border);
+}
+.room-subthread-head {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  margin-bottom: 0.75rem;
+}
+.room-subthread-head > h2 {
+  margin: 0;
+  font-size: 0.95rem;
+  font-weight: 600;
+}
diff --git a/apps/web/src/chat-path.ts b/apps/web/src/chat-path.ts
index 8a3c46d64..0c9faf4a3 100644
--- a/apps/web/src/chat-path.ts
+++ b/apps/web/src/chat-path.ts
@@ -12,6 +12,15 @@ export const chatKeys = {
   childTenants: (tenantId: string) => ["tenant", tenantId, "child-tenants"] as const,
 };
 
+/** One key factory per room (a workbench child tenant), so a send
+ * invalidates the room's timeline and roster together. */
+export const roomKeys = {
+  scope: (tenantId: string) => ["room", tenantId] as const,
+  tenant: (tenantId: string) => ["room", tenantId, "tenant"] as const,
+  participants: (tenantId: string) => ["room", tenantId, "participants"] as const,
+  timeline: (tenantId: string) => ["room", tenantId, "timeline"] as const,
+};
+
 export const CHATS_PATH_PREFIX = "/chats";
 export const NEW_CHAT_PATH = `${CHATS_PATH_PREFIX}/new`;
 
diff --git a/apps/web/src/chat/agent-display-names.test.ts b/apps/web/src/chat/agent-display-names.test.ts
deleted file mode 100644
index f9bb8c5bc..000000000
--- a/apps/web/src/chat/agent-display-names.test.ts
+++ /dev/null
@@ -1,38 +0,0 @@
-import { describe, expect, test } from "bun:test";
-
-import { agentDisplayNamesFromAgents, displayNameForAddress } from "./agent-display-names";
-
-describe("agentDisplayNamesFromAgents", () => {
-  test("keys each agent's display name by its participant address", () => {
-    const names = agentDisplayNamesFromAgents([
-      { address: "ins_echo@acme.example", displayName: "Myra" },
-      { address: "ins_review@acme.example", displayName: "Reviewer" },
-    ]);
-    expect(names.get("ins_echo@acme.example")).toBe("Myra");
-    expect(names.get("ins_review@acme.example")).toBe("Reviewer");
-  });
-
-  test("an empty snapshot builds an empty lookup", () => {
-    expect(agentDisplayNamesFromAgents([]).size).toBe(0);
-  });
-});
-
-describe("displayNameForAddress", () => {
-  test("returns the known display name, never the handle slug", () => {
-    const names = agentDisplayNamesFromAgents([
-      { address: "ins_echo@acme.example", displayName: "Myra" },
-    ]);
-    expect(displayNameForAddress("ins_echo@acme.example", names)).toBe("Myra");
-  });
-
-  test("is undefined for an unknown address so the caller falls back", () => {
-    const names = agentDisplayNamesFromAgents([
-      { address: "ins_echo@acme.example", displayName: "Myra" },
-    ]);
-    expect(displayNameForAddress("ins_other@acme.example", names)).toBeUndefined();
-  });
-
-  test("is undefined without a snapshot so the caller falls back", () => {
-    expect(displayNameForAddress("ins_echo@acme.example", undefined)).toBeUndefined();
-  });
-});
diff --git a/apps/web/src/chat/agent-display-names.ts b/apps/web/src/chat/agent-display-names.ts
deleted file mode 100644
index 66185409c..000000000
--- a/apps/web/src/chat/agent-display-names.ts
+++ /dev/null
@@ -1,34 +0,0 @@
-// Person-facing display names for a workbench's agent participants
-// — resolved once per workbench off
-// `GET /workbenches/:id/agents`' `displayName`, keyed by participant
-// address. Every surface that names an agent (timeline headers, mention
-// picker, typing pulse, presence stack, empty states, join lines) reads
-// through here so a reader sees the definition's display name — never a
-// raw handle slug. A missing entry falls back to the caller's own
-// slug-derived label: the agents query can still be in flight (or an
-// agent's definition gone) while the timeline already renders.
-
-/** Agent display names by participant address. */
-export type AgentDisplayNames = ReadonlyMap<string, string>;
-
-/**
- * Builds the lookup from a `listWorkbenchAgents` snapshot — one entry per
- * agent, keyed by the same address every participant record carries.
- */
-export function agentDisplayNamesFromAgents(
-  agents: readonly { readonly address: string; readonly displayName: string }[],
-): AgentDisplayNames {
-  return new Map(agents.map((agent) => [agent.address, agent.displayName] as const));
-}
-
-/**
- * The display name for an agent address when one is known — `undefined`
- * when the snapshot hasn't loaded or names no such agent, so the caller
- * falls back to its own slug-derived label rather than rendering a blank.
- */
-export function displayNameForAddress(
-  address: string,
-  displayNames: AgentDisplayNames | undefined,
-): string | undefined {
-  return displayNames?.get(address);
-}
diff --git a/apps/web/src/chat/api.ts b/apps/web/src/chat/api.ts
deleted file mode 100644
index 5bda41cf5..000000000
--- a/apps/web/src/chat/api.ts
+++ /dev/null
@@ -1,1040 +0,0 @@
-// The chat surface's one seam to the hub's chat HTTP routes (see
-// packages/chat/src/routes.ts, still the routes' implementation). Every
-// fetch the chat/* components make goes through a function here, and every
-// response is parsed with an arktype schema at the boundary — a route
-// shape change is a one-file fix.
-//
-// The wire-level `Part` and participant schemas live in this package's own
-// `./wire` (mirrored off the hub's wire contract) rather than being
-// imported from `@corbits/chat` directly, so this browser bundle never
-// carries a server-only dependency.
-
-import { type } from "arktype";
-import type { ArkErrors } from "arktype";
-import { Part } from "./wire/parts";
-import { parseParticipants } from "./wire/participants";
-import type { ParticipantRecord } from "./wire/participants";
-import { UnauthenticatedError } from "@/lib/api-query";
-import { InferenceSettingsApiError } from "@/settings/inference";
-import { CHAT_STRINGS } from "./strings";
-
-export {
-  TextPart,
-  ReasoningPart,
-  ToolTracePart,
-  BlockPart,
-  FilePart,
-  EventPart,
-  Part,
-} from "./wire/parts";
-export type { ParticipantRecord } from "./wire/participants";
-export const WorkbenchKind = type("'workbench' | 'chat'");
-export type WorkbenchKind = typeof WorkbenchKind.infer;
-
-/** Every workbench kind this UI has bespoke handling for. Any other value on
- * the wire is a workbench kind the server knows about that this UI doesn't —
- * it renders through the neutral, kind-agnostic path rather than being
- * rejected at parse time. */
-export function isKnownWorkbenchKind(kind: string): kind is WorkbenchKind {
-  return kind === "workbench" || kind === "chat";
-}
-
-const WorkbenchWire = type({
-  id: "string",
-  title: "string",
-  kind: "string",
-  pinned: "boolean",
-  "definitionId?": "string | null",
-  participants: "unknown[]",
-  "legacy?": "boolean",
-  // Row signals `GET /workbenches` annotates when it can resolve a
-  // workbench's mailbox (see `packages/chat/src/routes.ts`): absent,
-  // never a fabricated zero, for a workbench whose session isn't
-  // resolvable yet. `unreadCount` is the one exception — 0 is itself
-  // the honest "nothing unread" answer once a mailbox is resolved.
-  "unreadCount?": "number",
-  "lastActivityAt?": "string",
-  "live?": "'idle' | 'working' | 'reply-ready'",
-  // A bounded, text-only snippet of the newest message (see
-  // `packages/chat/src/codec.ts`'s `extractTextPreview`) — absent, never
-  // an empty string, when there is no message yet or it carries no text
-  // part.
-  "preview?": "string",
-  // `GET /workbenches` sets this server-side (see
-  // `packages/chat/src/routes.ts`) only for a workbench projected into
-  // this tenant via the shared-workbench machinery: "shared via
-  // parent · <parent name>" for true siblings, "shared · <owning tenant
-  // name>" otherwise. Absent for every ordinary, non-projected workbench.
-  "sharedLabel?": "string",
-  // The workbench's own workbench tenant (every workbench minted through
-  // POST /workbenches carries a tenancy link; null only on true legacy
-  // rows) — what per-workbench surfaces like Insights scope on, since
-  // the WORKBENCH id is a run id, never a tenant id.
-  "tenancy?": type({ tenantId: "string" }).or("null"),
-});
-
-const Workbench = WorkbenchWire.pipe((wire) => ({
-  ...wire,
-  participants: parseParticipants(wire.participants),
-}));
-export type Workbench = Omit<typeof WorkbenchWire.infer, "participants"> & {
-  readonly participants: readonly ParticipantRecord[];
-};
-
-const WorkbenchesResponse = type({ items: WorkbenchWire.array() }).pipe((response) => ({
-  items: response.items.map((wire) => ({
-    ...wire,
-    participants: parseParticipants(wire.participants),
-  })),
-}));
-
-// `tenantId`/`tenantName`/`tenantMonogram` are set server-side only for a
-// message sent by a shared workbench's "other side" participant — a share
-// member of a tenant this workbench was projected into (see
-// `resolveMessageSenderTenant` in `packages/chat/src/routes.ts`). Absent
-// for every ordinary same-tenant sender.
-export const MessageSender = type({
-  name: "string | null",
-  address: "string",
-  "tenantId?": "string",
-  "tenantName?": "string",
-  "tenantMonogram?": "string",
-});
-export type MessageSender = typeof MessageSender.infer;
-
-// `POST .../reactions/toggle`'s response shape, and the per-emoji entry
-// `GET /messages` batches onto every item's `reactions` array — see
-// `packages/chat/src/reactions.ts`'s `ReactionSummary`. `reactedByMe` is
-// this signed-in principal's own membership in the emoji's reactor set,
-// never another principal's.
-const ReactionSummaryWire = type({
-  emoji: "string",
-  count: "number",
-  reactedByMe: "boolean",
-});
-export type ReactionSummary = typeof ReactionSummaryWire.infer;
-
-const MessageItem = type({
-  id: "string",
-  createdAt: "string",
-  parts: Part.array(),
-  sender: MessageSender,
-  // Both fields are simply absent from the wire when the host never
-  // injected the corresponding store (see `CreateChatRoutesDeps` in
-  // `packages/chat/src/routes.ts`) — never a fabricated empty array or
-  // `false`, mirroring how `unreadCount` on `Workbench` works.
-  "reactions?": ReactionSummaryWire.array(),
-  "pinned?": "boolean",
-  // The client-generated send identity this message's own
-  // sender's composer submitted it with, echoed back once the server
-  // records it — see `sendMessage`'s `clientId` option and
-  // `packages/chat/src/client-ids.ts`. Absent for every message not
-  // sent with one (anything from before this feature, or from a peer
-  // whose own client never set it) — never a fabricated id.
-  "clientId?": "string",
-  // The thread this message belongs to, resolved server-side
-  // against the same "root feed by default" contract the per-thread
-  // feed filters on. Carrying it here is what lets one query serve the
-  // root feed and every open thread — see `./thread-feed.ts`. Absent
-  // on a host that mounts no thread store, matching `rootThreadId: ""`.
-  "threadId?": "string",
-  // The RFC 5322 `Message-ID` this row's mail carries — absent
-  // for a row with no mail original. This is what a reply's own
-  // `inReplyTo` threads onto, never this item's `id`, which for a
-  // mail-derived row is the mailbox's own local uid (see
-  // `mailbox-timeline.ts`'s `threadTreeToTimeline`).
-  "messageId?": "string",
-});
-export type MessageItem = typeof MessageItem.infer;
-
-const MessagesResponse = type({
-  items: MessageItem.array(),
-  "nextCursor?": "string",
-});
-export type MessagesResponse = typeof MessagesResponse.infer;
-
-const ReadState = type({
-  "lastSeenCreatedAt?": "string | null",
-  "lastSeenId?": "string | null",
-});
-
-// The shape `GET /api/tenants/:t/workflows/deployments` returns: a run, one row
-// per definition executing in the bench. It carries no display name — only
-// the id and the asset id its definition was hydrated from — so the mention
-// popover derives a readable label from `definitionAssetId` (see
-// `runDisplayName` below).
-const Run = type({
-  id: "string",
-  tenantId: "string",
-  definitionAssetId: "string",
-  status: "string",
-  createdAt: "string",
-});
-export type Run = typeof Run.infer;
-
-const RunsResponse = Run.array();
-
-// `GET /workbenches/:id/invitable` (see packages/chat/src/routes.ts): the
-// tenant's deployed, launchable workflow definitions this workbench can
-// invite an agent from — never including the workbench's own host.
-const InvitableDefinition = type({
-  id: "string",
-  name: "string",
-  "description?": "string",
-});
-export type InvitableDefinition = typeof InvitableDefinition.infer;
-
-const InvitableDefinitionsResponse = type({
-  items: InvitableDefinition.array(),
-});
-
-const InvitedAgent = type({ address: "string", definitionId: "string" });
-export type InvitedAgent = typeof InvitedAgent.infer;
-
-const RemovedParticipant = type({ address: "string" });
-
-export class ChatApiError extends Error {
-  constructor(
-    message: string,
-    readonly status?: number,
-  ) {
-    super(message);
-  }
-}
-
-/**
- * Plain-language copy for a failed chat request — never `error.message`
- * or `String(error)` verbatim, which for a `ChatApiError` embeds the raw
- * request path (see `request()` below). `InferenceSettingsApiError`
- * carries the envelope `userMessage` (safe to show) rather than a path,
- * so a 500 from `getResolvedCatalog` surfaces that sentence instead of
- * the generic fallback. Every chat-ui/chat-adjacent catch block that
- * surfaces an error to the user should call this rather than format one
- * of its own, so the class of leak (a raw `/api/...` URL or bare status
- * code in user-facing copy) has exactly one place to fix.
- */
-export function describeChatError(cause: unknown, fallback: string): string {
-  const statused =
-    cause instanceof ChatApiError || cause instanceof InferenceSettingsApiError ? cause : null;
-  if (statused === null) return fallback;
-  switch (statused.status) {
-    case 401:
-      return "You're signed out. Sign in again to continue.";
-    case 403:
-      return "You don't have access to this.";
-    case undefined:
-      return "Couldn't reach the server. Check your connection and try again.";
-    default: {
-      if (cause instanceof InferenceSettingsApiError && statused.message.trim() !== "") {
-        return statused.message;
-      }
-      return statused.status >= 500
-        ? "Something went wrong on our end. Try again in a moment."
-        : fallback;
-    }
-  }
-}
-
-type Validator<T> = (data: unknown) => T | ArkErrors;
-
-async function request<T>(path: string, schema: Validator<T>, init?: RequestInit): Promise<T> {
-  let response: Response;
-  try {
-    response = await fetch(path, {
-      ...init,
-      headers: { "content-type": "application/json", ...init?.headers },
-    });
-  } catch (cause) {
-    throw new ChatApiError(cause instanceof Error ? cause.message : String(cause));
-  }
-  if (response.status === 401) {
-    throw new UnauthenticatedError();
-  }
-  if (!response.ok) {
-    throw new ChatApiError(`The server answered ${response.status} for ${path}.`, response.status);
-  }
-  const body: unknown = await response.json().catch(() => undefined);
-  const parsed = schema(body);
-  if (parsed instanceof type.errors) {
-    throw new ChatApiError(`Unexpected response shape from ${path}: ${parsed.summary}`);
-  }
-  return parsed;
-}
-
-function workbenchesPath(tenantId: string, kind: WorkbenchKind): string {
-  return `/api/tenants/${tenantId}/chat/workbenches?kind=${kind}`;
-}
-
-/**
- * The shared TanStack Query key for `listWorkbenches(tenantId, kind)` —
- * defined here (not in the app's own key module) because this package owns
- * both the endpoint and `WorkbenchKind`. Every surface that lists workbenches of
- * a given kind (the shell's bench-activity, the command palette, the
- * Routines picker, this package's own `ChatWorkspace` sidebar) keys its
- * query with this function so they all subscribe to the one cached fetch
- * per (tenantId, kind) instead of each firing its own.
- */
-export function workbenchesQueryKey(
-  tenantId: string,
-  kind: WorkbenchKind,
-): readonly [string, string, string, WorkbenchKind] {
-  return ["tenant", tenantId, "workbenches", kind] as const;
-}
-
-/** Prefix covering every `workbenchesQueryKey` kind for a tenant — invalidate
- * this after a mutation (create, rename, pin) to refetch both kinds. */
-export function workbenchesQueryKeyPrefix(tenantId: string): readonly [string, string, string] {
-  return ["tenant", tenantId, "workbenches"] as const;
-}
-
-export function listWorkbenches(
-  tenantId: string,
-  kind: WorkbenchKind,
-): Promise<readonly Workbench[]> {
-  return request(workbenchesPath(tenantId, kind), WorkbenchesResponse).then((page) => page.items);
-}
-
-/**
- * Every workbench a tenant holds, of any kind — `kind` is optional
- * server-side (`packages/chat/src/routes.ts`'s `GET /workbenches`), and
- * workbench kinds are open-ended (`packages/chat/src/kinds.ts`), so this
- * omits the query param entirely rather than hardcoding the two kinds
- * this UI has bespoke handling for. Used where the caller needs the
- * complete workbench-host/participant surface regardless of kind — e.g.
- * the shell's second column splitting the result into its workbenches and
- * chats sections (see `apps/web/src/shell/bench-activity.ts`).
- */
-export function listAllWorkbenches(tenantId: string): Promise<readonly Workbench[]> {
-  return request(`/api/tenants/${tenantId}/chat/workbenches`, WorkbenchesResponse).then(
-    (page) => page.items,
-  );
-}
-
-// A chat is a direct thread with exactly one counterpart, picked at
-// creation and fixed for its lifetime: either an agent (`definitionId`)
-// or a bench member (`principalId`) — never both. The name is optional
-// either way (the server titles it by the counterpart's handle when
-// omitted). A workbench is the pinned, multiplayer kind: name-only, no
-// counterpart attached at creation. See `packages/chat/src/routes.ts`
-// `POST /workbenches` for the server side of this union.
-//
-// `kind: "chat"` + `definitionId` always find-or-reopens the one DM
-// for that agent. `reuseExisting` is still accepted on the
-// wire and ignored. `kind: "workbench"` mints an empty channel; a room's
-// onboarding walkthrough is posted separately through
-// `postWorkbenchOnboardingStep`, never as a side effect of create.
-export type CreateWorkbenchInput =
-  | {
-      readonly kind: "workbench";
-      readonly name: string;
-    }
-  | {
-      readonly kind: "chat";
-      readonly definitionId: string;
-      readonly name?: string;
-      readonly reuseExisting?: boolean;
-    }
-  | {
-      readonly kind: "chat";
-      readonly principalId: string;
-      readonly name?: string;
-    };
-
-/** Fired on `window` after every successful `createWorkbench`, carrying
- * `{tenantId}` in `detail`. The host shell's sidebar list caches its
- * workbench listings outside this package (see
- * `apps/web/src/shell/bench-activity.ts`), and creation happens at many
- * call sites (the picker dialog, agent launch, the land-hop) — one
- * signal here reaches them all, so a freshly minted workbench appears
- * in the sidebar without waiting for an unrelated refetch. */
-export const WORKBENCHES_MUTATED_EVENT = "workbench:chat:workbenches-mutated";
-
-/** SSE `event.type` the chat service publishes onto a workbench stream when
- * the tenant's workbench list changed (a specialist minted in the
- * background, a create from another tab). The host sidebar already
- * invalidates on `WORKBENCHES_MUTATED_EVENT`; `applyStreamWorkbenchesMutated`
- * is the bridge from this stream payload onto that same CustomEvent. */
-export const WORKBENCHES_MUTATED_STREAM_TYPE = "chat.workbenches-mutated";
-
-const WorkbenchesMutatedStreamData = type({
-  tenantId: "string",
-  "+": "ignore",
-});
-
-/** Parses a `chat.workbenches-mutated` SSE payload and, on success, fires
- * `WORKBENCHES_MUTATED_EVENT` with `{tenantId}` so the shell sidebar
- * refetches. Parse failure is a no-op — a malformed stream event must
- * never throw into the EventSource handler. Extra keys are ignored so
- * the server can grow the payload without breaking older clients. */
-export function applyStreamWorkbenchesMutated(data: unknown): void {
-  const parsed = WorkbenchesMutatedStreamData(data);
-  if (parsed instanceof type.errors) return;
-  if (typeof window === "undefined") return;
-  window.dispatchEvent(
-    new CustomEvent(WORKBENCHES_MUTATED_EVENT, {
-      detail: { tenantId: parsed.tenantId },
-    }),
-  );
-}
-
-export function createWorkbench(tenantId: string, input: CreateWorkbenchInput): Promise<Workbench> {
-  return request(`/api/tenants/${tenantId}/chat/workbenches`, Workbench, {
-    method: "POST",
-    body: JSON.stringify(input),
-  }).then((workbench) => {
-    if (typeof window !== "undefined") {
-      window.dispatchEvent(new CustomEvent(WORKBENCHES_MUTATED_EVENT, { detail: { tenantId } }));
-    }
-    return workbench;
-  });
-}
-
-export function listMessages(
-  tenantId: string,
-  workbenchId: string,
-  cursor?: string,
-): Promise<MessagesResponse> {
-  const query = cursor !== undefined ? `?cursor=${cursor}` : "";
-  return request(
-    `/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/messages${query}`,
-    MessagesResponse,
-  );
-}
-
-const BlobResponse = type({ contentBase64: "string" });
-
-/**
- * A `FilePart`'s bytes, base64-encoded (`GET /workbenches/:id/blobs/:blobId`).
- * There is no stored link from a chat blob to a Library artifact today —
- * this is the fallback read path a host uses to open a chat attachment
- * without one (see `chat-artifact-open.ts` in the web app).
- */
-export function fetchWorkbenchBlob(
-  tenantId: string,
-  workbenchId: string,
-  blobId: string,
-): Promise<string> {
-  return request(
-    `/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/blobs/${encodeURIComponent(blobId)}`,
-    BlobResponse,
-  ).then((body) => body.contentBase64);
-}
-
-// The wire response of `@corbits/mailbox`'s `POST /me/inbox/send`
-// The Sent-folder copy's own RFC 5322 `Message-ID` and its
-// mailbox uid, the same uid `mailbox-timeline.ts`'s `threadTreeToTimeline`
-// keys every timeline row by.
-const SentInboxMessage = type({
-  messageId: "string",
-  uid: "number",
-});
-export type SentInboxMessage = typeof SentInboxMessage.infer;
-
-/**
- * A human composer send, straight onto the tenant's own mailbox
- * (`POST /me/inbox/send`) — no chat route in between. `to` is
- * every other recipient address this send goes to; `inReplyTo` is the
- * RFC `Message-ID` of the message this one threads under (the thread
- * root when replying inside an open thread, or the specific message being
- * replied to when starting a new one) — never a mailbox uid, which is a
- * local, per-mailbox integer the wire format has no room for.
- */
-export function sendInboxMessage(
-  tenantId: string,
-  to: readonly string[],
-  body: string,
-  options?: { readonly inReplyTo?: string },
-): Promise<SentInboxMessage> {
-  const requestBody: Record<string, unknown> = { to, body };
-  if (options?.inReplyTo !== undefined) requestBody["inReplyTo"] = options.inReplyTo;
-  return request(`/api/tenants/${tenantId}/mailbox/me/inbox/send`, SentInboxMessage, {
-    method: "POST",
-    body: JSON.stringify(requestBody),
-  });
-}
-
-// `parentThreadId` is the thread this one hangs directly off: null for the
-// root thread, the root thread's id for a depth-1 thread, a depth-1
-// thread's id for a depth-2 sub-thread. Two levels, stop — see
-// `resolveThreadAnchor` in `packages/chat/src/threads.ts`.
-export const WorkbenchThread = type({
-  id: "string",
-  kind: "'root' | 'reply' | 'delivery'",
-  parentMessageId: "string | null",
-  parentThreadId: "string | null",
-  runRef: "string | null",
-  title: "string | null",
-  createdAt: "string",
-});
-export type WorkbenchThread = typeof WorkbenchThread.infer;
-
-// A listed thread carries its own reply activity — the
-// affordance on a parent message shows "N replies" and a last-activity
-// stamp, and computing those client-side meant a `GET
-// /threads/:id/messages` per thread on every timeline refresh. Only the
-// list response has these; `forkThread` and an open thread's own
-// `thread` field return the bare thread.
-export const WorkbenchThreadRow = WorkbenchThread.and({
-  replyCount: "number",
-  /** Null, never the thread's creation time, for a thread with no
-   * messages yet — an empty thread has had no activity. */
-  lastActivityAt: "string | null",
-});
-export type WorkbenchThreadRow = typeof WorkbenchThreadRow.infer;
-
-const ThreadsResponse = type({
-  rootThreadId: "string",
-  items: WorkbenchThreadRow.array(),
-});
-
-export function listThreads(
-  tenantId: string,
-  workbenchId: string,
-): Promise<{
-  readonly rootThreadId: string;
-  readonly items: readonly WorkbenchThreadRow[];
-}> {
-  return request(
-    `/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/threads`,
-    ThreadsResponse,
-  );
-}
-
-/**
- * A first-class fork: spawn a sub-thread rooted at any message inside a
- * thread — something Slack doesn't have. Idempotent per origin
- * message, and honors the two-level cap server-side: forking a message
- * already inside a sub-thread creates a sibling sub-thread under that
- * sub-thread's parent, never a third level (see `resolveThreadAnchor` in
- * `packages/chat/src/threads.ts`).
- */
-export function forkThread(
-  tenantId: string,
-  workbenchId: string,
-  parentMessageId: string,
-  title?: string,
-): Promise<WorkbenchThread> {
-  const body: Record<string, unknown> = { parentMessageId };
-  if (title !== undefined) body["title"] = title;
-  return request(
-    `/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/threads/fork`,
-    WorkbenchThread,
-    { method: "POST", body: JSON.stringify(body) },
-  );
-}
-
-export function putReadState(
-  tenantId: string,
-  workbenchId: string,
-  input: { readonly lastSeenCreatedAt: string; readonly lastSeenId: string },
-): Promise<void> {
-  return request(`/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/read-state`, ReadState, {
-    method: "PUT",
-    body: JSON.stringify(input),
-  }).then(() => undefined);
-}
-
-export function listRuns(tenantId: string): Promise<readonly Run[]> {
-  return request(`/api/tenants/${tenantId}/workflows/deployments`, RunsResponse);
-}
-
-export function listInvitableDefinitions(
-  tenantId: string,
-  workbenchId: string,
-): Promise<readonly InvitableDefinition[]> {
-  return request(
-    `/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/invitable`,
-    InvitableDefinitionsResponse,
-  ).then((page) => page.items);
-}
-
-/**
- * The tenant-wide invitable listing (`GET /invitable-definitions`) the
- * new-chat dialog reads before any workbench exists — the per-workbench
- * variant above 404s on a workbench id that isn't real.
- */
-export function listTenantInvitableDefinitions(
-  tenantId: string,
-): Promise<readonly InvitableDefinition[]> {
-  return request(
-    `/api/tenants/${tenantId}/chat/invitable-definitions`,
-    InvitableDefinitionsResponse,
-  ).then((page) => page.items);
-}
-
-export function inviteAgent(
-  tenantId: string,
-  workbenchId: string,
-  definitionId: string,
-): Promise<InvitedAgent> {
-  return request(`/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/invite`, InvitedAgent, {
-    method: "POST",
-    body: JSON.stringify({ definitionId }),
-  });
-}
-
-// `DELETE /workbenches/:id/participants/:address` (see
-// `packages/chat/src/routes.ts`): the removal counterpart to
-// `inviteAgent`/workbench creation's own join — drops the participant and,
-// for an invited agent, releases its launched instance server-side. The
-// Members section calls this per row and refetches `getWorkbenchSettings`
-// on success rather than trusting an optimistic local edit.
-export function removeWorkbenchParticipant(
-  tenantId: string,
-  workbenchId: string,
-  address: string,
-): Promise<void> {
-  return request(
-    `/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/participants/${encodeURIComponent(address)}`,
-    RemovedParticipant,
-    { method: "DELETE" },
-  ).then(() => undefined);
-}
-
-// `GET /workbenches/:id/agents` (see `packages/chat/src/routes.ts`): every
-// one of the workbench's agent participants, each resolved to the
-// definition id its name/instructions are read from and saved to via
-// `@corbits/agent-directory`'s own routes (see `getAgentInstructions`/
-// `updateAgentInstructions` below). A workbench with several invited
-// agents lists all of them, not just the first.
-const WorkbenchAgentWire = type({
-  address: "string",
-  handle: "string",
-  definitionId: "string",
-  definitionAssetId: "string",
-  displayName: "string",
-});
-export type WorkbenchAgent = typeof WorkbenchAgentWire.infer;
-
-const WorkbenchAgentsResponse = type({ items: WorkbenchAgentWire.array() });
-
-export function listWorkbenchAgents(
-  tenantId: string,
-  workbenchId: string,
-): Promise<readonly WorkbenchAgent[]> {
-  return request(
-    `/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/agents`,
-    WorkbenchAgentsResponse,
-  ).then((page) => page.items);
-}
-
-// `POST /workbenches/:id/agents/refresh` (see
-// `packages/chat/src/routes.ts`): recomputes the given agent's running
-// instance from its definition's CURRENT instructions — a wake replays
-// whatever the workbench's launch record holds verbatim, so a definition
-// edit reaches a running instance only after this call. The Assistant
-// section calls it right after `updateAgentInstructions` succeeds, so
-// the change is live for this workbench's agent from its next reply.
-export function refreshWorkbenchAgent(
-  tenantId: string,
-  workbenchId: string,
-  address: string,
-): Promise<void> {
-  return request(
-    `/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/agents/refresh`,
-    type({ ok: "boolean" }),
-    { method: "POST", body: JSON.stringify({ address }) },
-  ).then(() => undefined);
-}
-
-// `GET`/`PUT /api/tenants/:t/agent-definitions/:id` (see
-// `packages/agent-directory/src/routes.ts`): an agent's editable
-// persona — its display name and system prompt (surfaced to a person as
-// "instructions"). `name` here is the display name, matching the create
-// form's own "name" field (see `CreateAgentDefinitionInput`), never the
-// definition's immutable handle.
-const AgentCapabilitiesWire = type({
-  toolPackagePins: type({ name: "string", version: "string" }).array(),
-  skills: "string[]",
-  "model?": "string",
-});
-export type AgentCapabilities = typeof AgentCapabilitiesWire.infer;
-
-const AgentInstructionsWire = type({
-  name: "string",
-  systemPrompt: "string",
-});
-export type AgentInstructions = typeof AgentInstructionsWire.infer;
-
-/** `GET`/`POST .../restore`'s fuller shape: the editable persona plus its
- * current capability snapshot, in one read — the settings surface's
- * "Capabilities" list never needs a second round trip to show what an
- * agent already carries. */
-const AgentDetailWire = type({
-  name: "string",
-  systemPrompt: "string",
-  toolPackagePins: type({ name: "string", version: "string" }).array(),
-  skills: "string[]",
-  "model?": "string",
-});
-export type AgentDetail = typeof AgentDetailWire.infer;
-
-function agentInstructionsPath(tenantId: string, definitionId: string) {
-  return `/api/tenants/${tenantId}/agent-definitions/${encodeURIComponent(definitionId)}`;
-}
-
-// `GET /agent-definitions/visible` (see
-// `packages/agent-directory/src/visible-definitions.ts`): every agent
-// definition this tenant can open a direct chat with — its own, plus
-// every ancestor tenant's, a child's same-name definition shadowing an
-// ancestor's. `tenantId` here is the definition's OWNING tenant, which
-// is where its DM workbench actually lives — never necessarily the
-// caller's own tenant.
-const VisibleAgentDefinitionWire = type({
-  id: "string",
-  name: "string",
-  tenantId: "string",
-  tenantName: "string",
-  createdAt: "string",
-});
-export type VisibleAgentDefinition = typeof VisibleAgentDefinitionWire.infer;
-
-const VisibleAgentDefinitionsResponse = type({
-  definitions: VisibleAgentDefinitionWire.array(),
-});
-
-export function listVisibleAgentDefinitions(
-  tenantId: string,
-): Promise<readonly VisibleAgentDefinition[]> {
-  return request(
-    `/api/tenants/${tenantId}/agent-definitions/visible`,
-    VisibleAgentDefinitionsResponse,
-  ).then((page) => page.definitions);
-}
-
-/**
- * Opens a direct chat with an agent, minting it on first open and
- * reusing the same workbench on every later open — `packages/chat/src/
- * routes.ts`'s `POST /workbenches` with `reuseExisting: true` already
- * finds-or-creates by `chat/definitionId` (`findExistingAgentChat`), the
- * same seam the home-workbench land-hop uses. `tenantId` must be the
- * definition's OWNING tenant (see `VisibleAgentDefinition.tenantId`),
- * never the caller's own tenant when the agent was reached through
- * ancestor inheritance — the DM workbench lives where the agent lives.
- */
-export function openAgentDm(tenantId: string, definitionId: string): Promise<Workbench> {
-  return createWorkbench(tenantId, {
-    kind: "chat",
-    definitionId,
-    reuseExisting: true,
-  });
-}
-
-export function getAgentInstructions(tenantId: string, definitionId: string): Promise<AgentDetail> {
-  return request(agentInstructionsPath(tenantId, definitionId), AgentDetailWire);
-}
-
-export function updateAgentInstructions(
-  tenantId: string,
-  definitionId: string,
-  input: AgentInstructions,
-): Promise<AgentInstructions> {
-  return request(agentInstructionsPath(tenantId, definitionId), AgentInstructionsWire, {
-    method: "PUT",
-    body: JSON.stringify(input),
-  });
-}
-
-// `GET /:definitionId/versions` / `POST /:definitionId/restore` (see
-// `packages/agent-directory/src/routes.ts`): the agent's own instructions/
-// capabilities history, mirroring `@corbits/skills`' version-history shape
-// exactly (`commitSha`/`message`/`author`/`committedAtIso`/`current`) — the
-// sha only ever appears in a tooltip, never in the label a person reads.
-const AgentVersionWire = type({
-  commitSha: "string",
-  message: "string",
-  author: "string",
-  committedAtIso: "string",
-  current: "boolean",
-});
-export type AgentVersion = typeof AgentVersionWire.infer;
-
-export function listAgentVersions(
-  tenantId: string,
-  definitionId: string,
-): Promise<readonly AgentVersion[]> {
-  return request(
-    `${agentInstructionsPath(tenantId, definitionId)}/versions`,
-    type({ versions: AgentVersionWire.array() }),
-  ).then((page) => page.versions);
-}
-
-export function restoreAgentVersion(
-  tenantId: string,
-  definitionId: string,
-  commitSha: string,
-): Promise<AgentDetail> {
-  return request(`${agentInstructionsPath(tenantId, definitionId)}/restore`, AgentDetailWire, {
-    method: "POST",
-    body: JSON.stringify({ commitSha }),
-  });
-}
-
-// `GET /agent-definitions/capabilities/inventory` /
-// `POST /:definitionId/capabilities` (see `packages/agent-directory/src/
-// routes.ts`): the guided capability-add surface. The inventory call feeds
-// the add picker with only what this tenant actually has — a tool package,
-// skill, or model this call doesn't list can never be added, since the
-// server re-checks the same inventory fail-closed on the add itself.
-const CapabilityInventoryWire = type({
-  toolPackages: type({ name: "string" }).array(),
-  skills: type({ name: "string" }).array(),
-  models: type({ canonicalName: "string" }).array(),
-});
-export type CapabilityInventory = typeof CapabilityInventoryWire.infer;
-
-export function listCapabilityInventory(tenantId: string): Promise<CapabilityInventory> {
-  return request(
-    `/api/tenants/${tenantId}/agent-definitions/capabilities/inventory`,
-    CapabilityInventoryWire,
-  );
-}
-
-export type CapabilityAddition =
-  | { readonly kind: "toolPackage"; readonly name: string }
-  | { readonly kind: "skill"; readonly name: string }
-  | { readonly kind: "model"; readonly canonicalName: string };
-
-export function addAgentCapability(
-  tenantId: string,
-  definitionId: string,
-  addition: CapabilityAddition,
-): Promise<AgentCapabilities> {
-  return request(
-    `${agentInstructionsPath(tenantId, definitionId)}/capabilities`,
-    AgentCapabilitiesWire,
-    { method: "POST", body: JSON.stringify(addition) },
-  );
-}
-
-export function workbenchStreamUrl(tenantId: string, workbenchId: string): string {
-  return `/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/stream`;
-}
-
-/**
- * `POST .../presence` (see `packages/chat/src/routes.ts`): keeps
- * this principal's `lastActiveAt` fresh on the who's-here roster while its
- * stream connection sits open — "here at all" already comes for free from
- * the open connection itself, so this is called on real activity, never
- * on a polling interval. Best-effort: a dropped ping just means the next
- * one (or the eventual `"offline"` on disconnect) catches up.
- */
-export function pingWorkbenchPresence(tenantId: string, workbenchId: string): Promise<void> {
-  return fetch(`/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/presence`, {
-    method: "POST",
-  })
-    .then(() => undefined)
-    .catch(() => undefined);
-}
-
-// `chat/contextWindow`'s two-way "inherit vs override" resolution — see
-// `resolveContextWindow` in `packages/chat/src/workbench-settings.ts`, whose
-// server-side output this wire shape mirrors. `source` is what the settings
-// panel's "Use bench default (N)" vs override control reads to decide which
-// state it renders.
-export const ResolvedContextWindow = type({
-  value: "number",
-  source: "'inherit' | 'override'",
-});
-export type ResolvedContextWindow = typeof ResolvedContextWindow.infer;
-
-const WorkbenchSettingsResponse = WorkbenchWire.and({
-  settings: type("Record<string, unknown>"),
-  contextWindow: ResolvedContextWindow,
-}).pipe((wire) => ({
-  ...wire,
-  participants: parseParticipants(wire.participants),
-}));
-export type WorkbenchSettings = Omit<typeof WorkbenchSettingsResponse.infer, "participants"> & {
-  readonly participants: readonly ParticipantRecord[];
-};
-
-export function getWorkbenchSettings(
-  tenantId: string,
-  workbenchId: string,
-): Promise<WorkbenchSettings> {
-  return request(
-    `/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/settings`,
-    WorkbenchSettingsResponse,
-  );
-}
-
-/**
- * A `chat/*`-namespaced settings patch: name, purpose, pinned, and
- * context-window edits all go through this one function, matching the
- * single `PATCH /workbenches/:id/settings` route in
- * `packages/chat/src/routes.ts` that accepts any subset of them in one
- * body. `chat/contextWindow: null` clears
- * a workbench's override back to inheriting the bench default.
- */
-export type WorkbenchSettingsPatch = {
-  readonly "chat/kind"?: string;
-  readonly "chat/name"?: string;
-  readonly "chat/purpose"?: string;
-  readonly "chat/pinned"?: boolean;
-  readonly "chat/contextWindow"?: number | null;
-  /**
-   * `template/*` keys: the room's own record of which template minted
-   * it and what it still needs connected, per `@workbench/templates`'s
-   * own schema for this namespace. `chat`'s settings route validates
-   * only its own `chat/*` keys and passes any other namespace through
-   * opaquely (see `packages/chat/src/workbench-settings.ts`) — a
-   * `template/*` patch is validated by the caller
-   * (`apps/web/src/instant-agent-create.ts`) against that schema before
-   * it ever reaches this function.
-   */
-  readonly "template/id"?: string;
-  readonly "template/pendingConnections"?: readonly string[];
-};
-
-export function patchWorkbenchSettings(
-  tenantId: string,
-  workbenchId: string,
-  patch: WorkbenchSettingsPatch,
-): Promise<WorkbenchSettings> {
-  return request(
-    `/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/settings`,
-    WorkbenchSettingsResponse,
-    { method: "PATCH", body: JSON.stringify(patch) },
-  );
-}
-
-// Hub-zero T3: the room card's live state read and
-// start-reviewing write lived here, backed by the hub's now-deleted
-// workbench-scoped GitHub mount. GitHub connect/disconnect
-// itself stays native `connections/*` (`@/settings`); the card's
-// state/start rebind is a connections follow-up.
-
-// `GET`/`PATCH /bench/settings` (see `packages/chat/src/routes.ts`): the
-// bench-wide chat defaults every workbench inherits unless it sets its own
-// override. Currently just the default context window.
-const BenchChatSettingsResponse = type({
-  settings: "Record<string, unknown>",
-  contextWindow: "number",
-});
-export type BenchChatSettings = typeof BenchChatSettingsResponse.infer;
-
-export function getBenchChatSettings(tenantId: string): Promise<BenchChatSettings> {
-  return request(`/api/tenants/${tenantId}/chat/bench/settings`, BenchChatSettingsResponse);
-}
-
-export type BenchChatSettingsPatch = {
-  readonly "chat/contextWindow": number;
-};
-
-export function patchBenchChatSettings(
-  tenantId: string,
-  patch: BenchChatSettingsPatch,
-): Promise<BenchChatSettings> {
-  return request(`/api/tenants/${tenantId}/chat/bench/settings`, BenchChatSettingsResponse, {
-    method: "PATCH",
-    body: JSON.stringify(patch),
-  });
-}
-
-// The turn projection's read surface: what a client
-// reattaching to a workbench (page navigation, tab refocus, a dropped SSE
-// connection) uses to find whether a turn is still running and, if so,
-// replay whatever text it has already committed before the live stream's
-// tail resumes — see `GET /workbenches/:id/turns[/:turnId]` in
-// `packages/chat/src/routes.ts`.
-const AgentTurnWire = type({
-  id: "string",
-  workbenchId: "string",
-  agentAddress: "string",
-  childRunId: "string",
-  status: "'running' | 'completed' | 'failed' | 'cancelled'",
-  "replyMessageId?": "string | null",
-});
-export type AgentTurnSummary = typeof AgentTurnWire.infer;
-
-const AgentTurnsListWire = type({ items: AgentTurnWire.array() });
-
-function turnsPath(tenantId: string, workbenchId: string): string {
-  return `/api/tenants/${tenantId}/chat/workbenches/${workbenchId}/turns`;
-}
-
-export function listWorkbenchTurns(
-  tenantId: string,
-  workbenchId: string,
-): Promise<readonly AgentTurnSummary[]> {
-  return request(turnsPath(tenantId, workbenchId), AgentTurnsListWire).then((body) => body.items);
-}
-
-const AgentTurnDetailWire = AgentTurnWire.and({
-  "textSnapshot?": "string | null",
-});
-export type AgentTurnDetail = typeof AgentTurnDetailWire.infer;
-
-export function getWorkbenchTurn(
-  tenantId: string,
-  workbenchId: string,
-  turnId: string,
-): Promise<AgentTurnDetail> {
-  return request(`${turnsPath(tenantId, workbenchId)}/${turnId}`, AgentTurnDetailWire);
-}
-
-const CancelWorkbenchTurnWire = type({ cancelledCount: "number" });
-export type CancelWorkbenchTurnResult = typeof CancelWorkbenchTurnWire.infer;
-
-/**
- * Stops a workbench's in-flight turn(s) — `POST
- * .../turns/cancel` in `packages/chat/src/routes.ts`. `cancelledCount`
- * is the honest count of turns actually settled `cancelled`, not a
- * promise that the underlying agent process stopped: the
- * composer's own Stop affordance treats any non-throwing response as
- * "asked," and relies on the timeline's cancelled-turn notice — not this
- * response — to clear the typing indicator.
- */
-export function cancelWorkbenchTurn(
-  tenantId: string,
-  workbenchId: string,
-): Promise<CancelWorkbenchTurnResult> {
-  return request(`${turnsPath(tenantId, workbenchId)}/cancel`, CancelWorkbenchTurnWire, {
-    method: "POST",
-  });
-}
-
-/**
- * The newest still-`running` turn for `agentAddress`, or `null` if none —
- * what a remounting workbench asks on mount to know whether to hydrate its
- * streaming indicator immediately rather than wait for the next live event.
- * A 404 (no turn store injected on this deployment) reads the same as "no
- * running turn": the feature is simply unavailable, never an error the
- * caller needs to handle.
- */
-export async function fetchRunningTurn(
-  tenantId: string,
-  workbenchId: string,
-  agentAddress: string,
-): Promise<AgentTurnDetail | null> {
-  let turns: readonly AgentTurnSummary[];
-  try {
-    turns = await listWorkbenchTurns(tenantId, workbenchId);
-  } catch (cause) {
-    if (cause instanceof ChatApiError && cause.status === 404) return null;
-    throw cause;
-  }
-  const running = turns.find(
-    (turn) => turn.status === "running" && turn.agentAddress === agentAddress,
-  );
-  if (running === undefined) return null;
-  const detail = await getWorkbenchTurn(tenantId, workbenchId, running.id);
-  return { ...detail, textSnapshot: detail.textSnapshot ?? null };
-}
-
-/**
- * A readable name for a run, since the runs listing carries no name field:
- * the asset id's final path segment with any extension stripped, e.g.
- * `researcher/workflow.json` → "workflow". An asset id with no path shape
- * at all carries no readable segment to extract, so it renders friendly
- * placeholder copy — never the raw asset id.
- */
-export function runDisplayName(run: Run): string {
-  const slash = run.definitionAssetId.lastIndexOf("/");
-  if (slash < 0) return CHAT_STRINGS.unnamedRun;
-  const segment = run.definitionAssetId.slice(slash + 1);
-  if (segment.length === 0) return CHAT_STRINGS.unnamedRun;
-  const dot = segment.lastIndexOf(".");
-  return dot > 0 ? segment.slice(0, dot) : segment;
-}
diff --git a/apps/web/src/chat/artifact-chip.tsx b/apps/web/src/chat/artifact-chip.tsx
deleted file mode 100644
index 0a9073404..000000000
--- a/apps/web/src/chat/artifact-chip.tsx
+++ /dev/null
@@ -1,64 +0,0 @@
-// A message's `file` part is the wire shape for an artifact reference: it
-// always carries a name and media type, and carries `blobId` once the
-// platform has persisted the bytes, or `artifactId` when it also links back
-// to a Library row (`packages/chat/src/parts.ts`). Either one gives
-// the host a stable id to open — a still-in-flight `data`-only attachment
-// with neither renders the same chip, inert.
-//
-// Opening a chip is a callback the host supplies (mirrors `onOpenProfile`
-// and `onOpenThread` in `timeline.tsx`): this package owns no router. A
-// second, artifactId-only affordance — "Open in Artifacts" — hands the host a
-// separate callback so it can navigate there directly; it only
-// ever renders when `artifactId` is present, since a blob-only part has no
-// Library row to deep-link to.
-
-import { FileText, FolderOpen } from "@/lib/icons";
-
-import type { Part } from "./api";
-import { CHAT_STRINGS } from "./strings";
-
-export function ArtifactChip({
-  part,
-  onOpen,
-  onOpenInLibrary,
-}: {
-  readonly part: Part & { kind: "file" };
-  readonly onOpen?: (part: Part & { kind: "file" }) => void;
-  readonly onOpenInLibrary?: (part: Part & { kind: "file" }) => void;
-}) {
-  const openable =
-    (part.blobId !== undefined || part.artifactId !== undefined) && onOpen !== undefined;
-  const libraryOpenable = part.artifactId !== undefined && onOpenInLibrary !== undefined;
-
-  return (
-    <div className="chat-artifact-chip">
-      <button
-        type="button"
-        className="chat-artifact-chip-open"
-        disabled={!openable}
-        {...(openable && onOpen !== undefined ? { onClick: () => onOpen(part) } : {})}
-      >
-        <span className="chat-artifact-chip-icon" aria-hidden="true">
-          <FileText />
-        </span>
-        <span className="chat-artifact-chip-meta">
-          <strong>{part.name}</strong>
-          <span>
-            {CHAT_STRINGS.filePartLabel} · {part.mediaType}
-          </span>
-        </span>
-      </button>
-      {libraryOpenable && onOpenInLibrary !== undefined ? (
-        <button
-          type="button"
-          className="chat-artifact-chip-library"
-          aria-label="Open in Artifacts"
-          title="Open in Artifacts"
-          onClick={() => onOpenInLibrary(part)}
-        >
-          <FolderOpen />
-        </button>
-      ) : null}
-    </div>
-  );
-}
diff --git a/apps/web/src/chat/blocks/approve-block.test.tsx b/apps/web/src/chat/blocks/approve-block.test.tsx
deleted file mode 100644
index d8f54d3b3..000000000
--- a/apps/web/src/chat/blocks/approve-block.test.tsx
+++ /dev/null
@@ -1,383 +0,0 @@
-// DOM tests for the approve card's live round-trip. The host port
-// (`ApprovalActions`) is the mock boundary — a fake implementation stands in
-// for the host's fetch-backed reads/writes, the same way the block never
-// talks to `fetch` itself. Covers: pending+actable, pending+spectator,
-// approve success (through to the invalidation callback the host's real
-// port would run), approve failure (no fake resolution), an
-// already-resolved render, the platform-truth panel (never agent framing
-// alone next to live buttons), and the read-then-act conflict race.
-
-import { afterEach, describe, expect, test } from "bun:test";
-import { act } from "react";
-import { createRoot } from "react-dom/client";
-import type { Root } from "react-dom/client";
-
-import type {
-  ApprovalActions,
-  ApprovalDecisionResult,
-  ApprovalLiveStatus,
-  ApprovalStatusQuery,
-  PlatformApprovalDetail,
-} from "./approval-actions";
-import type { MessageItem } from "../api";
-import { WorkbenchTimeline } from "../timeline";
-
-const PLATFORM_DETAIL: PlatformApprovalDetail = {
-  agentName: "Payments Bot",
-  headline: "Wire $50,000 to acct_9182",
-  arguments: { destination: "acct_9182", amountUsd: "50000" },
-};
-
-function messageWithApproveBlock(approvalId: string): MessageItem[] {
-  return [
-    {
-      id: "m1",
-      createdAt: "2026-01-01T00:00:00.000Z",
-      parts: [
-        {
-          kind: "block",
-          block: {
-            type: "approve",
-            data: {
-              approvalId,
-              title: "Refresh cache",
-              risk: "low",
-              body: "Just a routine refresh, nothing to worry about!",
-            },
-          },
-        },
-      ],
-      sender: { name: "Researcher", address: "researcher@agents.example" },
-    },
-  ];
-}
-
-function fakeActions(overrides: Partial<ApprovalActions>): ApprovalActions {
-  return {
-    getStatus: async () => ({ kind: "loading" }) as ApprovalStatusQuery,
-    approve: async () => ({ kind: "resolved", status: "approved" }) as ApprovalDecisionResult,
-    reject: async () => ({ kind: "resolved", status: "rejected" }) as ApprovalDecisionResult,
-    ...overrides,
-  };
-}
-
-/** A stateful fake standing in for the host's read/write round-trip: a
- * decision actually changes what the next `getStatus` returns, the same
- * way the real platform's approve/reject + re-read behaves. Lets tests
- * exercise "the card re-syncs after any decision outcome" honestly instead
- * of asserting against a decision response the card is no longer supposed
- * to trust on its own. */
-function fakeBackend(
-  initialStatus: ApprovalLiveStatus,
-  canAct: boolean,
-  detail: PlatformApprovalDetail = PLATFORM_DETAIL,
-) {
-  let status = initialStatus;
-  const approveCalls: string[] = [];
-
-  const actions: ApprovalActions = {
-    getStatus: async () => ({ kind: "ready", status, canAct, detail }),
-    approve: async (id) => {
-      approveCalls.push(id);
-      status = "approved";
-      return { kind: "resolved", status: "approved" };
-    },
-    reject: async () => {
-      status = "rejected";
-      return { kind: "resolved", status: "rejected" };
-    },
-  };
-
-  return { actions, approveCalls };
-}
-
-let container: HTMLDivElement | null = null;
-let root: Root | null = null;
-
-afterEach(() => {
-  if (root !== null) act(() => root?.unmount());
-  container?.remove();
-  container = null;
-  root = null;
-});
-
-async function mount(actions: ApprovalActions, approvalId = "apv_1") {
-  container = document.createElement("div");
-  document.body.appendChild(container);
-  root = createRoot(container);
-  await act(async () => {
-    root?.render(
-      <WorkbenchTimeline items={messageWithApproveBlock(approvalId)} approvalActions={actions} />,
-    );
-  });
-  return container;
-}
-
-describe("approve card round-trip", () => {
-  test("binds approvalId from the gate-blocked approve block onto getStatus and decide", async () => {
-    // The orchestrator posts `{ approvalId: approval.id }` from the row
-    // `findByCorrelationId` resolved for the gate-blocked event. The card
-    // must pass that id through — never invent one, never drop it.
-    const approvalId = "apr_from_gate_blocked";
-    const statusIds: string[] = [];
-    const decideIds: string[] = [];
-    const actions = fakeActions({
-      getStatus: async (id) => {
-        statusIds.push(id);
-        return {
-          kind: "ready",
-          status: "pending",
-          canAct: true,
-          detail: PLATFORM_DETAIL,
-        };
-      },
-      approve: async (id) => {
-        decideIds.push(id);
-        return { kind: "resolved", status: "approved" };
-      },
-    });
-    const el = await mount(actions, approvalId);
-
-    expect(statusIds).toEqual([approvalId]);
-
-    const approveButton = el.querySelector(".chat-block-actions button") as HTMLButtonElement;
-    await act(async () => {
-      approveButton.click();
-    });
-    expect(decideIds).toEqual([approvalId]);
-    // Re-sync after decide also keys off the same bound id.
-    expect(statusIds).toEqual([approvalId, approvalId]);
-  });
-
-  test("pending + actable: buttons render enabled and call the port", async () => {
-    const backend = fakeBackend("pending", true);
-    const el = await mount(backend.actions);
-
-    const buttons = el.querySelectorAll(".chat-block-actions button");
-    expect(buttons).toHaveLength(2);
-    expect((buttons[0] as HTMLButtonElement).disabled).toBe(false);
-    expect((buttons[1] as HTMLButtonElement).disabled).toBe(false);
-
-    await act(async () => {
-      (buttons[0] as HTMLButtonElement).click();
-    });
-
-    expect(backend.approveCalls).toEqual(["apv_1"]);
-    expect(el.textContent).toContain("Approved");
-  });
-
-  test("pending + spectator: status and platform detail shown, no buttons", async () => {
-    const el = await mount(fakeBackend("pending", false).actions);
-
-    expect(el.querySelectorAll(".chat-block-actions button")).toHaveLength(0);
-    expect(el.textContent).toContain("This one isn't yours to decide.");
-    expect(el.textContent).toContain("Wire $50,000 to acct_9182");
-  });
-
-  test("the platform's own headline and arguments render, always ahead of the agent's framing", async () => {
-    const el = await mount(fakeBackend("pending", true).actions);
-
-    expect(el.textContent).toContain("Payments Bot is asking to");
-    expect(el.textContent).toContain("Wire $50,000 to acct_9182");
-    expect(el.textContent).toContain("acct_9182");
-    expect(el.textContent).toContain("50000");
-
-    // Both the platform truth and the agent's own (demoted) framing are on
-    // the page, but the platform detail must appear first in document
-    // order — never the agent's framing standing in ahead of it.
-    const platformIndex = el.innerHTML.indexOf("Wire $50,000 to acct_9182");
-    const agentIndex = el.innerHTML.indexOf("Just a routine refresh, nothing to worry about!");
-    expect(platformIndex).toBeGreaterThan(-1);
-    expect(agentIndex).toBeGreaterThan(-1);
-    expect(platformIndex).toBeLessThan(agentIndex);
-  });
-
-  test("a forbidden status read renders live buttons with NO description at all — never the agent's framing standing in for the platform's", async () => {
-    const el = await mount(
-      fakeActions({
-        getStatus: async () => ({ kind: "forbidden" }),
-        approve: async () => ({ kind: "forbidden", message: "nope" }),
-      }),
-    );
-
-    const buttons = el.querySelectorAll(".chat-block-actions button");
-    expect(buttons).toHaveLength(2);
-    expect((buttons[0] as HTMLButtonElement).disabled).toBe(false);
-
-    // The agent's own body text — the exact confused-deputy risk (an
-    // innocuous "Refresh cache" framing over a real wire transfer) — must
-    // never render as the description sitting next to live buttons.
-    expect(el.textContent).not.toContain("Just a routine refresh, nothing to worry about!");
-
-    await act(async () => {
-      (buttons[0] as HTMLButtonElement).click();
-    });
-    expect(el.textContent).toContain("You do not have permission to act on this.");
-  });
-
-  test("approve success re-renders resolved state from a re-read and invalidates", async () => {
-    let invalidated = false;
-    const backend = fakeBackend("pending", true);
-    const originalApprove = backend.actions.approve;
-    const actions: ApprovalActions = {
-      ...backend.actions,
-      approve: async (id) => {
-        invalidated = true; // stands in for the host's queryClient.invalidateQueries
-        return originalApprove(id);
-      },
-    };
-    const el = await mount(actions);
-
-    const approveButton = el.querySelector(".chat-block-actions button") as HTMLButtonElement;
-    await act(async () => {
-      approveButton.click();
-    });
-
-    expect(invalidated).toBe(true);
-    expect(el.querySelectorAll(".chat-block-actions button")).toHaveLength(0);
-    expect(el.textContent).toContain("Approved");
-  });
-
-  test("approve failure re-syncs from a read and never fakes resolution", async () => {
-    const el = await mount(
-      fakeActions({
-        getStatus: async () => ({
-          kind: "ready",
-          status: "pending",
-          canAct: true,
-          detail: PLATFORM_DETAIL,
-        }),
-        approve: async () => ({ kind: "error", message: "network down" }),
-      }),
-    );
-
-    const approveButton = el.querySelector(".chat-block-actions button") as HTMLButtonElement;
-    await act(async () => {
-      approveButton.click();
-    });
-
-    expect(el.textContent).toContain("Couldn't reach the approval");
-    expect(el.textContent).not.toContain("Approved");
-    // Buttons remain — the re-read still says pending, not silently resolved.
-    expect(el.querySelectorAll(".chat-block-actions button")).toHaveLength(2);
-  });
-
-  test("read-then-act race: a conflict re-fetches and renders the resolved state, buttons gone", async () => {
-    let reads = 0;
-    const actions: ApprovalActions = {
-      getStatus: async () => {
-        reads += 1;
-        // First read (initial mount): still pending, actionable. Second
-        // read (after the conflicting decision): someone else got there
-        // first and it's now approved.
-        return reads === 1
-          ? {
-              kind: "ready",
-              status: "pending",
-              canAct: true,
-              detail: PLATFORM_DETAIL,
-            }
-          : {
-              kind: "ready",
-              status: "approved",
-              canAct: false,
-              detail: PLATFORM_DETAIL,
-            };
-      },
-      approve: async () => ({ kind: "conflict", message: "already resolved" }),
-      reject: async () => ({ kind: "resolved", status: "rejected" }),
-    };
-    const el = await mount(actions);
-
-    const approveButton = el.querySelector(".chat-block-actions button") as HTMLButtonElement;
-    await act(async () => {
-      approveButton.click();
-    });
-
-    expect(reads).toBe(2);
-    expect(el.querySelectorAll(".chat-block-actions button")).toHaveLength(0);
-    expect(el.textContent).toContain("Approved");
-    expect(el.textContent).toContain("Someone else already resolved this while you were deciding.");
-  });
-
-  test("an already-resolved approval renders calmly with no buttons", async () => {
-    const el = await mount(fakeBackend("rejected", true).actions);
-
-    expect(el.querySelectorAll(".chat-block-actions button")).toHaveLength(0);
-    expect(el.textContent).toContain("Denied");
-  });
-
-  test("the primary button carries the platform detail's own verb, and deny is generic", async () => {
-    const el = await mount(
-      fakeBackend("pending", true, {
-        ...PLATFORM_DETAIL,
-        actionVerb: "Merge it",
-      }).actions,
-    );
-
-    const buttons = el.querySelectorAll(".chat-block-actions button");
-    expect(buttons.item(0).textContent).toBe("Merge it");
-    expect(buttons.item(1).textContent).toBe("Not now");
-  });
-
-  test("with no platform-supplied verb, the primary button falls back to the generic label", async () => {
-    const el = await mount(fakeBackend("pending", true).actions);
-
-    const buttons = el.querySelectorAll(".chat-block-actions button");
-    expect(buttons.item(0).textContent).toBe("Approve");
-  });
-
-  test("the platform's consequence sentence renders in place of a risk badge", async () => {
-    const el = await mount(
-      fakeBackend("pending", true, {
-        ...PLATFORM_DETAIL,
-        consequence: "Merging goes further than posting a review — it puts the change live.",
-      }).actions,
-    );
-
-    expect(el.textContent).toContain(
-      "Merging goes further than posting a review — it puts the change live.",
-    );
-    expect(el.querySelector(".chat-block-risk")).toBeNull();
-  });
-
-  test("the standing-consent link only shows when the host offers both the capability and the detail", async () => {
-    const withoutCapability = await mount(
-      fakeBackend("pending", true, {
-        ...PLATFORM_DETAIL,
-        standingConsent: { verb: "merging", resource: "acme/checkout" },
-      }).actions,
-    );
-    expect(withoutCapability.textContent).not.toContain("Allow merging for");
-
-    const backend = fakeBackend("pending", true, {
-      ...PLATFORM_DETAIL,
-      standingConsent: { verb: "merging", resource: "acme/checkout" },
-    });
-    const allowStandingCalls: string[] = [];
-    const el = await mount(
-      {
-        ...backend.actions,
-        allowStanding: async (id) => {
-          allowStandingCalls.push(id);
-          return { kind: "resolved", status: "approved" };
-        },
-      },
-      "apv_2",
-    );
-
-    expect(el.textContent).toContain("Allow merging for acme/checkout");
-    const link = Array.from(el.querySelectorAll("button")).find(
-      (button) => button.textContent === "Allow merging for acme/checkout",
-    ) as HTMLButtonElement;
-    await act(async () => {
-      link.click();
-    });
-    expect(allowStandingCalls).toEqual(["apv_2"]);
-  });
-
-  test("no capability, no detail field: the standing-consent link never appears", async () => {
-    const el = await mount(fakeBackend("pending", true).actions);
-    expect(el.textContent).not.toContain("Allow ");
-  });
-});
diff --git a/apps/web/src/chat/chat-workspace.test.ts b/apps/web/src/chat/chat-workspace.test.ts
deleted file mode 100644
index 082eeecd7..000000000
--- a/apps/web/src/chat/chat-workspace.test.ts
+++ /dev/null
@@ -1,77 +0,0 @@
-import { describe, expect, test } from "bun:test";
-
-import { buildMemberAvatarStack } from "./chat-workspace";
-import type { ParticipantRecord } from "./api";
-import { avatarClassForPrincipal } from "./avatar";
-
-describe("buildMemberAvatarStack", () => {
-  test("identifies agent participants with agent tone for Corbit rendering", () => {
-    const participants: readonly ParticipantRecord[] = [
-      { address: "run_myra@dana.localhost", handle: "myra" },
-      { address: "run_scout@dana.localhost", handle: "scout" },
-    ];
-
-    const stack = buildMemberAvatarStack(participants);
-
-    expect(stack).toHaveLength(2);
-    expect(stack.map((entry) => entry.label)).toEqual(["Myra", "Scout"]);
-    expect(stack.every((entry) => entry.tone === "agent")).toBe(true);
-  });
-
-  test("is the static roster only — live presence is a separate stack", () => {
-    const participants: readonly ParticipantRecord[] = [
-      { address: "run_myra@dana.localhost", handle: "myra" },
-      { address: "run_scout@dana.localhost", handle: "scout" },
-    ];
-
-    const stack = buildMemberAvatarStack(participants);
-
-    expect(stack.map((entry) => entry.label)).toEqual(["Myra", "Scout"]);
-    expect(stack.every((entry) => entry.tone === "agent")).toBe(true);
-  });
-
-  test("includes the signed-in human from the roster even with empty presence", () => {
-    // Onboarding/template rooms list the human as a participant before any
-    // presence snapshot arrives — the stack must not be agent-only.
-    const participants: readonly ParticipantRecord[] = [
-      { address: "run_myra@dana.localhost", handle: "myra" },
-      { address: "prn_dana", handle: "Dana" },
-    ];
-
-    const stack = buildMemberAvatarStack(participants);
-
-    expect(stack.map((entry) => entry.label)).toEqual(["Myra", "Dana"]);
-    expect(stack.map((entry) => entry.tone)).toEqual(["agent", "neutral"]);
-    const human = stack[1];
-    expect(human?.key).toBe("prn_dana");
-    expect(human?.initials).toBe("D");
-    expect(human?.avatarClassName).toBe(avatarClassForPrincipal("prn_dana"));
-  });
-
-  test("prefers the signed-in display name over a raw participant handle", () => {
-    const participants: readonly ParticipantRecord[] = [
-      { address: "prn_self", handle: "ada-handle" },
-    ];
-
-    const stack = buildMemberAvatarStack(participants, undefined, {
-      principalId: "prn_self",
-      name: "Ada Lovelace",
-    });
-
-    expect(stack.map((entry) => entry.label)).toEqual(["Ada Lovelace"]);
-    expect(stack.map((entry) => entry.initials)).toEqual(["A"]);
-  });
-
-  test("prefers resolved agent display names over handle slugs", () => {
-    const participants: readonly ParticipantRecord[] = [
-      { address: "run_myra@dana.localhost", handle: "myra" },
-    ];
-
-    const stack = buildMemberAvatarStack(
-      participants,
-      new Map([["run_myra@dana.localhost", "Myra the Helper"]]),
-    );
-
-    expect(stack.map((entry) => entry.label)).toEqual(["Myra the Helper"]);
-  });
-});
diff --git a/apps/web/src/chat/chat-workspace.tsx b/apps/web/src/chat/chat-workspace.tsx
deleted file mode 100644
index 311f495c0..000000000
--- a/apps/web/src/chat/chat-workspace.tsx
+++ /dev/null
@@ -1,1619 +0,0 @@
-// Chat workspace: the host resolves which bench the signed-in
-// account chats in, loads its workbenches and deployed agents, and wires the
-// timeline and composer together for whichever workbench is
-// selected. Workbench list lives in the shell contextual panel — this
-// surface is the active conversation only.
-//
-// Resolving *which* bench that is is host-specific (it rides on
-// whatever session/query plumbing the embedding app already has — in
-// `@workbench/web` that is the same `/api/me/principals` call the Home
-// and Settings pages use), so `ChatWorkspace` takes a small
-// `TenantResolution` value rather than importing app code: the same
-// narrow-port shape the hub's chat routes uses for `ChatPlatform`.
-
-import { isAgentAddress } from "./wire/mentions";
-import { Button, EmptyState, toast } from "@corbits/react-ui";
-import { reportError } from "@corbits/error-sink";
-import { getResolvedCatalog } from "@/settings/inference";
-import { CaretDown, ChatCircle, SlidersHorizontal, WarningCircle } from "@/lib/icons";
-import { useQuery, useQueryClient } from "@tanstack/react-query";
-import { useCallback, useEffect, useMemo, useRef, useState } from "react";
-import type { ReactNode } from "react";
-
-import {
-  workbenchesQueryKey,
-  workbenchesQueryKeyPrefix,
-  cancelWorkbenchTurn,
-  describeChatError,
-  fetchRunningTurn,
-  listWorkbenches,
-  listWorkbenchAgents,
-  addAgentCapability,
-  refreshWorkbenchAgent,
-  pingWorkbenchPresence,
-  workbenchStreamUrl,
-  isKnownWorkbenchKind,
-  WORKBENCHES_MUTATED_STREAM_TYPE,
-  applyStreamWorkbenchesMutated,
-} from "./api";
-import type { Workbench, ParticipantRecord, Part } from "./api";
-import { WorkbenchSettingsSurface } from "./workbench-settings";
-import type { WorkbenchSettingsSectionId } from "./workbench-settings";
-import { Composer } from "./composer";
-import type { ComposerHandle } from "./composer";
-import { WorkbenchLoadingState } from "./loading-state";
-import { mentionCandidatesFromParticipants } from "./mentions";
-import { failedTurnModelChoices, failedTurnToolCapableModelChoices } from "./failed-turn-models";
-import { CHAT_STRINGS } from "./strings";
-import { displayWorkbenchTitle } from "./workbench-display-title";
-import {
-  useStreamingReply,
-  isAwaitingReply,
-  lastHumanMessageParts,
-  typingAgentNames,
-} from "./streaming-reply";
-import { useTurnActivity, TurnActivityStrip } from "./turn-activity";
-import type { StreamingReplyState } from "./streaming-reply";
-import {
-  AgentBadge,
-  WorkbenchTimeline,
-  displayNameFromHandle,
-  localPartOf,
-  messageText,
-} from "./timeline";
-import type { FailedTurnRecovery } from "./timeline";
-import {
-  agentDisplayNamesFromAgents,
-  displayNameForAddress,
-  type AgentDisplayNames,
-} from "./agent-display-names";
-import { NoUsableModelBanner } from "./no-usable-model-banner";
-import { ResumeFailedBanner } from "./resume-failed-banner";
-import type { CurrentUser, ScrollSnapshot, TimelineMessageItem } from "./timeline";
-import type { ApprovalActions } from "./blocks/approval-actions";
-import type { ConnectServiceActions } from "./blocks/connect-service-actions";
-import {
-  typingLabel,
-  TypingIndicator,
-  AgentTypingIndicator,
-  useTypingIndicator,
-} from "./typing-indicator";
-import type { ProfileSubject } from "./profile-subject";
-import { useWorkbenchStream } from "./use-workbench-stream";
-import { useWorkbenchFeed } from "./use-workbench-feed";
-import { CorbitAvatar, avatarClassForPrincipal } from "./avatar";
-import { useWorkbenchPresenceRoster } from "./workbench-presence";
-import { type } from "arktype";
-import { ChatMessageEventData, ChatSettingsEventData } from "./wire/stream-events";
-import { useThreadNavigation } from "./use-thread-navigation";
-import { mergePendingSends, useOptimisticSends } from "./use-optimistic-sends";
-export { mergePendingSends, pendingSenderAddress } from "./use-optimistic-sends";
-export type { PendingSend } from "./use-optimistic-sends";
-import { useWorkbenchTimelineView } from "./workbench-timeline-view";
-export { chatFeedQueryKeyPrefix, chatThreadsQueryKey } from "./use-workbench-feed";
-export type { MessagesState } from "./workbench-timeline-view";
-
-/**
- * The host's answer to "which bench does this account chat in": mirrors
- * the loading/unauthenticated/error/ready shape every hub-backed query
- * in the embedding app already uses, plus `"empty"` for an
- * authenticated account with no bench membership at all.
- */
-export type TenantResolution =
-  | { readonly kind: "loading" }
-  | { readonly kind: "unauthenticated" }
-  | { readonly kind: "error"; readonly message: string }
-  | { readonly kind: "empty" }
-  | { readonly kind: "ready"; readonly tenantId: string };
-
-/**
- * One live presence entry for the workbench's who's-here stack —
- * derived from this workbench's own `/stream` connection
- * (`useWorkbenchPresenceRoster`), never a second connection or an HTTP
- * heartbeat poll. The roster carries only ids, so display names and avatar
- * classes resolve client-side against the workbench's participants.
- */
-export interface PresenceMember {
-  readonly principalId: string;
-  readonly displayName: string;
-  readonly avatarClassName: string;
-}
-
-/** One entry in the header's static member stack — an agent or a roster
- * human, normalized to the one shape the square stack renders. Live
- * presence uses `PresenceMember` in a separate round stack. */
-export interface TeamAvatarEntry {
-  readonly key: string;
-  readonly initials: string;
-  readonly label: string;
-  readonly tone: "agent" | "neutral";
-  readonly avatarClassName?: string;
-}
-
-/** How many avatars the header shows before collapsing the rest into a
- * "+N" chip. Shared by the static member stack and the live presence
- * stack so neither overflows the 3rem bar. */
-export const TEAM_AVATAR_STACK_LIMIT = 6;
-
-/** A crumb the host's `StageTopBar` can render — label plus an optional
- * parent href. The last crumb is the current page. */
-export type ChatHeaderCrumb = {
-  readonly label: string;
-  readonly href?: string;
-};
-
-/** Chrome the host lifts into `StageTopBar` (`crumbs` / `subtitle` /
- * `actions`) so `/w` does not keep a second identity row. */
-export type ChatHeaderChrome = {
-  readonly crumbs: readonly ChatHeaderCrumb[];
-  readonly subtitle?: ReactNode;
-  readonly actions?: ReactNode;
-};
-
-const WORKBENCHES_LIST_CHROME: ChatHeaderChrome = {
-  crumbs: [{ label: CHAT_STRINGS.chatsSectionLabel }],
-};
-
-/**
- * The workbench's static member stack: every agent participant plus every
- * human on the roster. Agents first (they have no presence concept of
- * their own); humans follow. Roster humans are included even when live
- * presence is empty — onboarding/template rooms often list the
- * signed-in human as a participant before any `chat.presence.snapshot`
- * arrives. Live who's-here is a separate round stack, not mixed in here.
- *
- * Each person gets a stable generated color keyed by address. Human labels
- * prefer `currentUser.name` when the roster entry
- * is the signed-in reader — never a raw handle when a display name exists.
- */
-export function buildMemberAvatarStack(
-  participants: readonly ParticipantRecord[],
-  displayNames?: AgentDisplayNames,
-  currentUser?: CurrentUser,
-): readonly TeamAvatarEntry[] {
-  const agents = participants
-    .filter((participant) => isAgentAddress(participant.address))
-    .map((participant) => {
-      const label =
-        displayNameForAddress(participant.address, displayNames) ??
-        displayNameFromHandle(participant.handle);
-      return {
-        key: participant.address,
-        initials: "",
-        label,
-        tone: "agent" as const,
-      };
-    });
-
-  const humans = participants
-    .filter((participant) => !isAgentAddress(participant.address))
-    .map((participant) => {
-      const label = typingLabel(localPartOf(participant.address), participants, currentUser);
-      return {
-        key: participant.address,
-        initials: label.slice(0, 1).toUpperCase(),
-        label,
-        tone: "neutral" as const,
-        avatarClassName: avatarClassForPrincipal(participant.address),
-      };
-    });
-
-  return [...agents, ...humans];
-}
-
-type WorkbenchesState =
-  | { readonly kind: "loading" }
-  | { readonly kind: "error"; readonly message: string }
-  | {
-      readonly kind: "ready";
-      readonly workbenches: readonly Workbench[];
-      readonly chats: readonly Workbench[];
-    };
-
-/**
- * Recovery controls for a gone / non-workbench id. Prefer the
- * Mission Control + New workbench pair; fall back to the legacy single
- * "Back to workbenches" action when a host has not wired the new props.
- */
-export function workbenchNotFoundRecoveryAction(args: {
-  readonly onGoToMissionControl?: () => void;
-  readonly onNewWorkbench?: () => void;
-  readonly onBackToWorkbenchList?: () => void;
-}): ReactNode | undefined {
-  const { onGoToMissionControl, onNewWorkbench, onBackToWorkbenchList } = args;
-  const hasModernRecovery = onGoToMissionControl !== undefined || onNewWorkbench !== undefined;
-  if (hasModernRecovery) {
-    return (
-      <>
-        {onGoToMissionControl !== undefined ? (
-          <Button variant="outline" onClick={onGoToMissionControl}>
-            {CHAT_STRINGS.workbenchNotFoundMissionControlAction}
-          </Button>
-        ) : null}
-        {onNewWorkbench !== undefined ? (
-          <Button variant="outline" onClick={onNewWorkbench}>
-            {CHAT_STRINGS.workbenchNotFoundNewWorkbenchAction}
-          </Button>
-        ) : null}
-      </>
-    );
-  }
-  if (onBackToWorkbenchList !== undefined) {
-    return (
-      <Button variant="outline" onClick={onBackToWorkbenchList}>
-        {CHAT_STRINGS.workbenchNotFoundAction}
-      </Button>
-    );
-  }
-  return undefined;
-}
-
-/**
- * The composer's placeholder reads as a direct message once the active
- * surface is a chat, naming its one counterpart — a chat's title always
- * defaults to that counterpart's name at creation (see `routes.ts`'s
- * `POST /workbenches`), so it's always the right word here even when the
- * counterpart is a person, not an agent. A workbench (or a surface that
- * hasn't resolved yet) keeps the generic, mention-driven copy.
- */
-export function composerPlaceholderFor(
-  workbench:
-    | {
-        readonly kind: string;
-        readonly title: string;
-      }
-    | undefined,
-): string {
-  if (workbench === undefined || workbench.kind !== "chat") {
-    return CHAT_STRINGS.composerPlaceholder;
-  }
-  const counterpart =
-    workbench.title.trim().length > 0 ? workbench.title : CHAT_STRINGS.unnamedWorkbench;
-  return CHAT_STRINGS.composerPlaceholderChat(counterpart);
-}
-
-/**
- * A composer submit this workspace has optimistically added to the
- * timeline before the server confirms it — see `TimelineMessageItem`'s
- * `pendingStatus`. `nonce` is this workspace's own client-side key,
- * independent of any server-issued message id (which does not exist yet
- * while `status` is `"sending"`, and never will if it ends up discarded).
- */
-
-/** The one client-side id `mergeStreamingReply` gives its synthetic
- * timeline item — stable across renders (React's reconciliation key) and
- * never mistaken for a server-issued message id (those come back from
- * `POST`/`GET` routes with a different shape). */
-const STREAMING_REPLY_ITEM_ID = "streaming_reply";
-
-/** The workbench's first agent participant — the best available
- * attribution for a synthetic timeline item that has no real sender of
- * its own (`chat.agent` events carry none, and a client-side timeout
- * notice never had a server-issued sender to begin with). Workbenches
- * with more than one invited agent are a known approximation here, not a
- * regression — today's non-streaming refetch has the same "which agent
- * replied" gap until the persisted message's real sender lands. */
-function firstAgentParticipant(
-  participants: readonly ParticipantRecord[],
-): ParticipantRecord | undefined {
-  return participants.find((participant) => isAgentAddress(participant.address));
-}
-
-/**
- * Folds the active turn's in-progress reply onto the end of the timeline,
- * exactly the way `mergePendingSends` folds this reader's own optimistic
- * sends — except this synthetic item is the *other* side's message, so it
- * needs a sender to attribute it to (see `firstAgentParticipant`).
- */
-export function mergeStreamingReply(
-  items: readonly TimelineMessageItem[],
-  streamingReply: StreamingReplyState,
-  participants: readonly ParticipantRecord[],
-): readonly TimelineMessageItem[] {
-  // A pending reply with no tokens yet stays off the timeline — an
-  // empty bubble with no timestamp reads as broken; the typing pulse
-  // in the incoming-message slot owns that phase until the first delta
-  // lands. A `"replied"` turn renders nothing: its reply is already a
-  // persisted message.
-  if (streamingReply === null || streamingReply.phase === "replied" || streamingReply.text === "") {
-    return items;
-  }
-  const agent = firstAgentParticipant(participants);
-  if (agent === undefined) return items;
-  return [
-    ...items,
-    {
-      id: STREAMING_REPLY_ITEM_ID,
-      createdAt: new Date().toISOString(),
-      parts: [{ kind: "text", text: streamingReply.text }],
-      sender: { name: null, address: agent.address },
-      streaming: true,
-    },
-  ];
-}
-
-/** The client-side id the reply-timeout notice renders under — same
- * "never a server-issued id" contract as `STREAMING_REPLY_ITEM_ID`. */
-const REPLY_TIMED_OUT_ITEM_ID = "reply_timed_out_notice";
-
-/**
- * Appends an honest inline notice once `useStreamingReply`'s own backstop
- * (`PENDING_REPLY_CLEAR_MS`) has fired — a turn that opened but never got a
- * single token and never closed out either, so the reader was left staring
- * at a typing indicator that just vanished with no explanation. This is
- * the same class of failure `postUndeliveredNotice` (the hub's chat routes)
- * already gives an honest, actionable backstop to when the dispatch fails
- * loud enough for the server to see it — a cold-waking agent that never
- * streams a token back fails silently instead, so this synthetic notice
- * carries a `turnFailed` text part exactly like the
- * server's own notice (`replyTimedOutRefId` is minted by `reportError` at
- * the moment `useStreamingReply`'s timer fires), so it renders through
- * `FailedTurnStrip` — same ref-quotable copy, same Retry action — instead
- * of a second, weaker backstop living beside the real one.
- */
-export function appendReplyTimedOutNotice(
-  items: readonly TimelineMessageItem[],
-  replyTimedOutRefId: string | null,
-  participants: readonly ParticipantRecord[],
-): readonly TimelineMessageItem[] {
-  if (replyTimedOutRefId === null) return items;
-  const agent = firstAgentParticipant(participants);
-  return [
-    ...items,
-    {
-      id: REPLY_TIMED_OUT_ITEM_ID,
-      createdAt: new Date().toISOString(),
-      parts: [
-        {
-          kind: "text",
-          text: `${CHAT_STRINGS.replyTimedOutNotice} (ref ${replyTimedOutRefId})`,
-          turnFailed: true,
-        },
-      ],
-      sender: { name: null, address: agent?.address ?? "" },
-    },
-  ];
-}
-
-/**
- * Records one workbench's scroll snapshot into the map, pure — a fresh `Map`
- * copy rather than a mutation, so `scrollSnapshotsRef.current` always holds
- * exactly the value this function returned, never a same-reference object
- * mutated out from under a caller still holding the old one.
- */
-export function withScrollSnapshot(
-  snapshots: ReadonlyMap<string, ScrollSnapshot>,
-  workbenchId: string,
-  snapshot: ScrollSnapshot,
-): ReadonlyMap<string, ScrollSnapshot> {
-  const next = new Map(snapshots);
-  next.set(workbenchId, snapshot);
-  return next;
-}
-
-/**
- * Workbenches and chats via TanStack Query, keyed with `workbenchesQueryKey` —
- * the same key `apps/web`'s shell bands and command palette use, so this
- * sidebar shares one in-flight fetch per (tenantId, kind) with the rest of
- * the shell rather than firing its own independent request on every mount.
- */
-function useWorkbenchLists(tenantId: string) {
-  const workbenches = useQuery({
-    queryKey: workbenchesQueryKey(tenantId, "workbench"),
-    queryFn: () => listWorkbenches(tenantId, "workbench"),
-  });
-  const chats = useQuery({
-    queryKey: workbenchesQueryKey(tenantId, "chat"),
-    queryFn: () => listWorkbenches(tenantId, "chat"),
-  });
-
-  const reload = useCallback(async () => {
-    await Promise.all([workbenches.refetch(), chats.refetch()]);
-  }, [workbenches.refetch, chats.refetch]);
-
-  // Referentially stable across renders that don't actually change the
-  // underlying data — a fresh object literal here every render would make
-  // `workbenchesState` look "changed" to every effect that depends on it
-  // (the auto-select-first-workbench effect below included), firing them on
-  // every unrelated re-render rather than only when workbenches/chats data
-  // itself moves.
-  const state: WorkbenchesState = useMemo(() => {
-    if (workbenches.isError) {
-      return {
-        kind: "error",
-        message: describeChatError(workbenches.error, "Couldn't load workbenches."),
-      };
-    }
-    if (chats.isError) {
-      return {
-        kind: "error",
-        message: describeChatError(chats.error, "Couldn't load workbenches."),
-      };
-    }
-    if (workbenches.data === undefined || chats.data === undefined) {
-      return { kind: "loading" };
-    }
-    return { kind: "ready", workbenches: workbenches.data, chats: chats.data };
-  }, [
-    workbenches.isError,
-    workbenches.error,
-    workbenches.data,
-    chats.isError,
-    chats.error,
-    chats.data,
-  ]);
-
-  return { state, reload };
-}
-
-function ChatWorkspaceInner({
-  tenantId,
-  workbenchId: controlledWorkbenchId,
-  onWorkbenchChange,
-  currentUser,
-  onOpenProfile,
-  settingsOpen = false,
-  onSettingsOpenChange,
-  settingsSection = "general",
-  onSettingsSectionChange,
-  settingsEntityId = null,
-  onSettingsEntityIdChange,
-  onOpenArtifact,
-  onOpenArtifactInLibrary,
-  onFixConnection,
-  approvalActions,
-  connectServiceActions,
-  headerLeading,
-  headerSlot,
-  registerComposerInsert,
-  onWorkbenchNotFound,
-  onBackToWorkbenchList,
-  onGoToMissionControl,
-  onNewWorkbench,
-  onSignIn,
-  hasUsableModel,
-  onConnectModel,
-}: {
-  readonly tenantId: string;
-  readonly workbenchId?: string | null;
-  readonly onWorkbenchChange?: (workbenchId: string) => void;
-  readonly currentUser?: CurrentUser;
-  readonly onOpenProfile?: (subject: ProfileSubject) => void;
-  /** Whether the routed workbench's settings surface should replace the
-   * conversation stage (mock § Workbench settings — a full surface, never a
-   * dialog). Host-controlled the same way `workbenchId` is: driven from the
-   * URL (`/w/:id/settings`). */
-  readonly settingsOpen?: boolean;
-  /** Fired when the settings surface should open or close. `section` is
-   * only passed on open — the section the opener meant to land on (the
-   * gear button's General, or the composer's `/agents` shortcut) — so the
-   * host can navigate straight to that URL without a second, separate
-   * navigation for the section. */
-  readonly onSettingsOpenChange?: (
-    open: boolean,
-    section?: WorkbenchSettingsSectionId,
-    entityId?: string,
-  ) => void;
-  /** Which workbench settings tab is active while the surface is open —
-   * host-controlled the same way `settingsOpen` is, driven from the URL
-   * (`/w/:id/settings/:section`). */
-  readonly settingsSection?: WorkbenchSettingsSectionId;
-  /** Fired when the user switches tabs while the settings surface is
-   * already open, so the host can reflect it in the URL. */
-  readonly onSettingsSectionChange?: (section: WorkbenchSettingsSectionId) => void;
-  /** Section sub-selection while settings are open — host-controlled from
-   * the URL (`/w/:id/settings/:section/:entityId`). `null` means the
-   * section's own list (or a section with no list). */
-  readonly settingsEntityId?: string | null;
-  /** Fired when a settings section opens or closes its own detail, so the
-   * host can deepen or clear the entity segment in the URL. */
-  readonly onSettingsEntityIdChange?: (entityId: string | null) => void;
-  /** Open a message's artifact chip — see `WorkbenchTimeline`'s `onOpenArtifact`. */
-  readonly onOpenArtifact?: (part: Part & { kind: "file" }) => void;
-  /** The chip's "Open in Library" affordance — see `WorkbenchTimeline`'s
-   * `onOpenArtifactInLibrary`. */
-  readonly onOpenArtifactInLibrary?: (part: Part & { kind: "file" }) => void;
-  /** The classified-inference-failure text bubble's "Fix this connection"
-   * action — see `WorkbenchTimeline`'s `onFixConnection`. */
-  readonly onFixConnection?: () => void;
-  /** The approve block's live round-trip — see `WorkbenchTimeline`'s
-   * `approvalActions`. */
-  readonly approvalActions?: ApprovalActions;
-  /** Host round-trip for the generic "connect-service" card. Undefined
-   * renders every connect-service card in its disconnected framing. */
-  readonly connectServiceActions?: ConnectServiceActions;
-  /** Host-supplied control rendered first in the workbench header — the
-   * shell's single col2 toggle, so chat carries the same top-bar chrome as
-   * every other stage surface. Unused when `headerSlot` owns the bar. */
-  readonly headerLeading?: ReactNode;
-  /** Host-owned stage bar. When set, identity and primary actions render
-   * through this slot (`StageTopBar`'s crumbs / subtitle / actions) instead
-   * of `.chat-workbench-header`. */
-  readonly headerSlot?: (chrome: ChatHeaderChrome) => ReactNode;
-  /**
-   * Lets the host (command palette, canvas "insert into composer", …) push
-   * text into the live composer. Called with the insert fn when a composer
-   * mounts, and with `null` when it unmounts so the host never holds a
-   * stale handle. Optional: hosts that don't need the insert path omit it.
-   */
-  readonly registerComposerInsert?: (insert: ((text: string) => void) | null) => void;
-  /** Fired when the routed workbench 404s — a deleted workbench, or a stale
-   * Recents entry that outlived it. The host owns Recents (this package
-   * never touches localStorage), so it's told rather than reaching out. */
-  readonly onWorkbenchNotFound?: (workbenchId: string) => void;
-  /** Legacy single recovery for a gone workbench — prefer
-   * `onGoToMissionControl` / `onNewWorkbench`. */
-  readonly onBackToWorkbenchList?: () => void;
-  /** Not-found empty state's Mission Control recovery. */
-  readonly onGoToMissionControl?: () => void;
-  /** Not-found empty state's New workbench recovery. */
-  readonly onNewWorkbench?: () => void;
-  /** The 401 messages-error state's way out — sign back in instead of a
-   * retry that can only ever hit the same 401. Omitted, that state falls
-   * back to no action at all (never "Try again" for a session that's gone). */
-  readonly onSignIn?: () => void;
-  /** Whether this tenant can actually run inference right now — the
-   * host's read of `hasUsableModel` (`@/settings/inference`)
-   * against its resolved catalog, never mere `model_provider` row
-   * presence. `undefined` while that read is still in flight:
-   * the banner stays hidden rather than flashing "no model" before the
-   * real answer lands. */
-  readonly hasUsableModel?: boolean;
-  /** The pre-send banner's "Connect a model" action — the host's own
-   * navigation into Settings → AI providers. Undefined still renders the
-   * banner, just with an inert button, matching every other optional
-   * action this file wires. */
-  readonly onConnectModel?: () => void;
-}) {
-  const queryClient = useQueryClient();
-  const refreshWorkbenchLists = useCallback(() => {
-    void queryClient.invalidateQueries({
-      queryKey: workbenchesQueryKeyPrefix(tenantId),
-    });
-  }, [queryClient, tenantId]);
-  const { state: workbenchesState, reload: reloadWorkbenches } = useWorkbenchLists(tenantId);
-  const [selectedWorkbenchId, setSelectedWorkbenchId] = useState<string | null>(null);
-  const activeWorkbenchId = controlledWorkbenchId ?? selectedWorkbenchId;
-  const setActiveWorkbenchId = (id: string) => {
-    setSelectedWorkbenchId(id);
-    onWorkbenchChange?.(id);
-  };
-  // Catch-up `fetchRunningTurn` failure must surface a banner with
-  // Retry — never look idle. `resumeAttempt` re-arms the effect on Retry.
-  const [resumeFailedRefId, setResumeFailedRefId] = useState<string | null>(null);
-  const [resumeAttempt, setResumeAttempt] = useState(0);
-  // null = workbench root feed. A concrete id opens that thread in the same
-  // geometry (timeline + composer). pendingParentMessageId is set when the
-  // user opens a reply on a message that has no thread yet.
-  // Thread navigation is resolved after the feed below, which it reads.
-  // This composer's own optimistic sends — see `mergePendingSends`. A
-  // workbench switch drops whatever was pending in the previous workbench:
-  // its composer submit targeted that workbench, not wherever the reader
-  // navigated to next.
-
-  const composerRef = useRef<ComposerHandle>(null);
-
-  const feed = useWorkbenchFeed({
-    tenantId,
-    activeWorkbenchId,
-    ...(onWorkbenchNotFound !== undefined ? { onWorkbenchNotFound } : {}),
-  });
-  const { threads, rootThreadId, refreshFeed } = feed;
-
-  const navigation = useThreadNavigation({
-    tenantId,
-    activeWorkbenchId,
-    threads,
-    rootThreadId,
-    threadsLoaded: feed.threadsLoaded,
-    refetchThreads: feed.refetchThreads,
-  });
-  const {
-    openThreadId,
-    pendingParentMessageId,
-    inThreadView,
-    openThreadParent,
-    threadTitle,
-    depth1Threads,
-    subThreadsByParentId,
-    openThreadForMessage,
-    forkMessage,
-    openThreadById,
-    closeThread,
-  } = navigation;
-
-  const { messagesState, threadMetaByMessageId } = useWorkbenchTimelineView({
-    tenantId,
-    activeWorkbenchId,
-    feed,
-    navigation,
-  });
-
-  // Picking a default workbench is this component's own fallback for "no
-  // workbench named in the URL yet".
-  useEffect(() => {
-    if (workbenchesState.kind !== "ready") return;
-    if (activeWorkbenchId !== null) return;
-    const first = workbenchesState.workbenches[0] ?? workbenchesState.chats[0];
-    if (first !== undefined) setActiveWorkbenchId(first.id);
-  }, [workbenchesState, activeWorkbenchId]);
-
-  // This rethrows after
-  // toasting — the composer's own `onStop` awaits the returned promise
-  // and re-enables its Stop button on rejection, so a genuinely failed
-  // request (network, a denied grant) never leaves the button stuck
-  // disabled for the rest of the turn. The timeline's cancelled-turn
-  // notice, not this response, is what actually clears the typing
-  // indicator once (or if) the turn settles.
-  const handleStopTurn = useCallback(() => {
-    if (activeWorkbenchId === null) return Promise.resolve();
-    return cancelWorkbenchTurn(tenantId, activeWorkbenchId).catch((err) => {
-      toast(CHAT_STRINGS.turnCancelError);
-      throw err;
-    });
-  }, [tenantId, activeWorkbenchId]);
-
-  const composerMounted =
-    !settingsOpen && activeWorkbenchId !== null && messagesState.kind === "ready";
-
-  useEffect(() => {
-    if (registerComposerInsert === undefined) return;
-    if (!composerMounted) {
-      registerComposerInsert(null);
-      return;
-    }
-    registerComposerInsert((text) => composerRef.current?.insertText(text));
-    return () => registerComposerInsert(null);
-  }, [registerComposerInsert, composerMounted]);
-
-  const { typingState, handleStreamEvent: handleTypingEvent } = useTypingIndicator(
-    currentUser?.principalId,
-    activeWorkbenchId,
-  );
-  const {
-    streamingReply,
-    replyTimedOutRefId,
-    handleStreamEvent: handleStreamingReplyEvent,
-    noteAwaitingReply,
-    resumeFromTurn,
-  } = useStreamingReply(activeWorkbenchId);
-  const { activity: turnActivity, handleStreamEvent: handleTurnActivityEvent } =
-    useTurnActivity(activeWorkbenchId);
-  const { roster: presenceRoster, handleStreamEvent: handlePresenceEvent } =
-    useWorkbenchPresenceRoster(activeWorkbenchId);
-
-  // "Here at all" comes for free from the open `/stream` connection itself
-  // (see `packages/chat/src/workbench-presence.ts`) — this ping only
-  // refreshes `lastActiveAt` for a tab that's been backgrounded a while,
-  // fired on the reader actually coming back rather than on an interval.
-  useEffect(() => {
-    if (activeWorkbenchId === null) return;
-    const onVisibility = () => {
-      if (document.visibilityState !== "visible") return;
-      void pingWorkbenchPresence(tenantId, activeWorkbenchId);
-    };
-    document.addEventListener("visibilitychange", onVisibility);
-    return () => document.removeEventListener("visibilitychange", onVisibility);
-  }, [tenantId, activeWorkbenchId]);
-
-  // Opening Settings swaps `WorkbenchTimeline` out for `WorkbenchSettingsSurface`
-  // entirely (see the early `settingsOpen` return below) — closing it
-  // remounts a fresh `WorkbenchTimeline` with no memory of where the reader
-  // was. A ref (not state) holds each workbench's last snapshot: recording it
-  // never needs to trigger a re-render, only be there the next time this
-  // workbench's `WorkbenchTimeline` mounts.
-  const scrollSnapshotsRef = useRef<ReadonlyMap<string, ScrollSnapshot>>(new Map());
-  const restoredScrollSnapshot =
-    activeWorkbenchId !== null ? scrollSnapshotsRef.current.get(activeWorkbenchId) : undefined;
-  const handleScrollSnapshot = useCallback(
-    (snapshot: ScrollSnapshot) => {
-      if (activeWorkbenchId === null) return;
-      scrollSnapshotsRef.current = withScrollSnapshot(
-        scrollSnapshotsRef.current,
-        activeWorkbenchId,
-        snapshot,
-      );
-    },
-    [activeWorkbenchId],
-  );
-
-  // Every event applies straight into the query cache it describes rather
-  // than triggering a refetch: each payload already
-  // carries what a subscriber needs, so there is no "invalidate, then
-  // fetch" fallback left beside this. `chat.agent` needs no cache
-  // application of its own — it's fully owned by
-  // `handleStreamingReplyEvent`/`handleTurnActivityEvent`, and the real
-  // message it eventually produces arrives as its own `chat.message`.
-  useWorkbenchStream(
-    activeWorkbenchId !== null ? workbenchStreamUrl(tenantId, activeWorkbenchId) : "",
-    (eventType, data) => {
-      handleTypingEvent(eventType, data);
-      handleStreamingReplyEvent(eventType, data);
-      handleTurnActivityEvent(eventType, data);
-      handlePresenceEvent(eventType, data);
-      if (activeWorkbenchId === null) return;
-      switch (eventType) {
-        case "chat.message": {
-          // The feed now reads from the mailbox, not this stream's own
-          // `chat.message` payload — the mailbox's own
-          // `/me/inbox/events` subscription (see `useWorkbenchFeed`) is
-          // what refreshes the timeline once the fan-out lands. A parse
-          // failure here still means something arrived this connection
-          // couldn't read, so still worth a refresh.
-          const parsed = ChatMessageEventData(data);
-          if (parsed instanceof type.errors) {
-            toast(CHAT_STRINGS.streamMessageDropped);
-            refreshFeed();
-          }
-          break;
-        }
-        case "chat.settings": {
-          const parsed = ChatSettingsEventData(data);
-          if (!(parsed instanceof type.errors)) {
-            connectServiceActions?.notifySettingsChanged().catch((cause) => {
-              reportError(cause, {
-                operation: "chat.notifyServiceSettingsChanged",
-                tenantId,
-                roomId: activeWorkbenchId,
-              });
-            });
-          }
-          break;
-        }
-        case WORKBENCHES_MUTATED_STREAM_TYPE: {
-          applyStreamWorkbenchesMutated(data);
-          break;
-        }
-      }
-    },
-    refreshFeed,
-    {},
-    (eventType) => {
-      if (eventType !== "chat.message") return;
-      toast(CHAT_STRINGS.streamMessageDropped);
-      refreshFeed();
-    },
-  );
-
-  /** The one door into the workbench settings surface — the gear button and
-   * the composer's `/agents` command both go through this so the section
-   * that lands is always the one the caller meant to open. */
-  function openWorkbenchSettings(
-    section: WorkbenchSettingsSectionId = "general",
-    entityId?: string,
-  ) {
-    onSettingsOpenChange?.(true, section, entityId);
-  }
-
-  /**
-   * The optimistic core both a fresh composer submit and a bubble's own
-   * Retry button drive: adds (or resets) a pending entry before the
-   * request goes out, so the sender sees their message land in the
-   * timeline immediately rather than waiting on the round-trip. Once the
-   * POST resolves, the confirmed item (built straight from its response —
-   * no extra round-trip) replaces the pending entry in the very same
-   * state update: there is never a render where the message has vanished
-   * from both `pendingSends` and `messagesState.items` while a fresh
-   * `GET` is still in flight to reintroduce it, and never a render where
-   * both the pending and confirmed copies show at once. The follow-up
-   * background `loadMessages` still runs to pick up server-only detail
-   * (real sender record, reactions, thread meta) — it settles into that
-   * data under the same `clientId` key, so it never re-triggers the
-   * mount/unmount swap this replaces. A rejected send flips the pending
-   * entry to `"failed"` in place instead — never a status line
-   * disconnected from the message it describes.
-   */
-  const activeWorkbench =
-    workbenchesState.kind === "ready"
-      ? [...workbenchesState.workbenches, ...workbenchesState.chats].find(
-          (workbench) => workbench.id === activeWorkbenchId,
-        )
-      : undefined;
-  const activeWorkbenchDisplayTitle =
-    activeWorkbench !== undefined
-      ? displayWorkbenchTitle(activeWorkbench.title, activeWorkbench.id)
-      : undefined;
-  const isActiveChat =
-    activeWorkbench !== undefined &&
-    isKnownWorkbenchKind(activeWorkbench.kind) &&
-    activeWorkbench.kind === "chat";
-  const activeChatAgent = isActiveChat
-    ? activeWorkbench?.participants.find((participant) => isAgentAddress(participant.address))
-    : undefined;
-
-  const hasAgentParticipant = (activeWorkbench?.participants ?? []).some((participant) =>
-    isAgentAddress(participant.address),
-  );
-
-  const resumeAgentAddress = (activeWorkbench?.participants ?? []).find((participant) =>
-    isAgentAddress(participant.address),
-  )?.address;
-
-  // A turn runs entirely server-side — this component mounting or
-  // unmounting never starts or stops it (see `useWorkbenchStream`'s own
-  // header: unmount only closes the `EventSource`, nothing server-side).
-  // So a fresh mount (first visit, or a return after navigating away while
-  // a reply was still streaming) asks once whether the agent has a turn
-  // still running and, if so, replays its committed text immediately
-  // rather than showing nothing until the next live token arrives. Any
-  // live event that beats this fetch back always wins — see
-  // `resumeFromTurn`'s own guard.
-  // A failed catch-up must not swallow into idle — report a ref
-  // and keep `ResumeFailedBanner` visible until Retry succeeds (or the
-  // workbench changes).
-  useEffect(() => {
-    if (activeWorkbenchId === null || resumeAgentAddress === undefined) {
-      setResumeFailedRefId(null);
-      return;
-    }
-    let cancelled = false;
-    fetchRunningTurn(tenantId, activeWorkbenchId, resumeAgentAddress)
-      .then((runningTurn) => {
-        if (cancelled) return;
-        setResumeFailedRefId(null);
-        resumeFromTurn(runningTurn);
-      })
-      .catch((cause) => {
-        if (cancelled) return;
-        const refId = reportError(cause, {
-          operation: "chat.resumeRunningTurn",
-          tenantId,
-          roomId: activeWorkbenchId,
-          agentId: resumeAgentAddress,
-        });
-        setResumeFailedRefId(refId);
-      });
-    return () => {
-      cancelled = true;
-    };
-  }, [tenantId, activeWorkbenchId, resumeAgentAddress, resumeAttempt]);
-
-  const handleRetryResume = useCallback(() => {
-    setResumeAttempt((attempt) => attempt + 1);
-  }, []);
-
-  // Every other participant's address — the signed-in sender's
-  // own entry (matched by local-part against `principalId`, the same
-  // convention `typingLabel` above reads) never belongs in its own `to`.
-  const recipientAddresses = (activeWorkbench?.participants ?? [])
-    .map((participant) => participant.address)
-    .filter((address) => localPartOf(address) !== currentUser?.principalId);
-
-  const { pendingSends, handleSend, retryPendingSend, discardPendingSend } = useOptimisticSends({
-    tenantId,
-    activeWorkbenchId,
-    currentUserPrincipalId: currentUser?.principalId,
-    openThreadId,
-    pendingParentMessageId,
-    openThreadById,
-    recipientAddresses,
-    messages: feed.loadedMessages,
-    noteAwaitingReply,
-    hasAgentParticipant,
-    restoreDraft: (text) => composerRef.current?.insertText(text),
-  });
-
-  /** Retry on a failed-turn strip: sends the recovered text
-   * (`findRetryText`) straight back through the normal send path — same
-   * as the person typing it and hitting Enter — rather than parking it
-   * in the composer for them to resend by hand. */
-  const handleRetryFailedTurn = useCallback(
-    async (_item: TimelineMessageItem, retryText?: string) => {
-      if (retryText === undefined) return;
-      await handleSend({ text: retryText, attachments: [] });
-    },
-    [handleSend],
-  );
-
-  const catalogQuery = useQuery({
-    queryKey: ["tenant", tenantId, "resolved-catalog"],
-    queryFn: () => getResolvedCatalog(tenantId),
-  });
-  const workbenchAgentsQuery = useQuery({
-    queryKey: ["tenant", tenantId, "chat", "workbench-agents", activeWorkbenchId],
-    queryFn: () =>
-      activeWorkbenchId !== null
-        ? listWorkbenchAgents(tenantId, activeWorkbenchId)
-        : Promise.resolve([]),
-    enabled: activeWorkbenchId !== null,
-  });
-  // Person-facing display names for this workbench's agents,
-  // keyed by participant address. Memoized so `MessageParts`'s memo guard
-  // keeps working: a fresh Map every render would read as new
-  // props on every row and re-render the whole timeline per token.
-  const agentDisplayNames: AgentDisplayNames = useMemo(
-    () => agentDisplayNamesFromAgents(workbenchAgentsQuery.data ?? []),
-    [workbenchAgentsQuery.data],
-  );
-  const failedTurnRecovery = useMemo((): FailedTurnRecovery => {
-    const definitionIdByAddress: Record<string, string> = {};
-    for (const agent of workbenchAgentsQuery.data ?? []) {
-      definitionIdByAddress[agent.address] = agent.definitionId;
-    }
-    return {
-      models: failedTurnModelChoices(catalogQuery.data ?? []),
-      toolCapableModels: failedTurnToolCapableModelChoices(catalogQuery.data ?? []),
-      definitionIdByAddress,
-      onApplyModel: async ({ definitionId, address, canonicalName }) => {
-        if (activeWorkbenchId === null) return;
-        await addAgentCapability(tenantId, definitionId, {
-          kind: "model",
-          canonicalName,
-        });
-        await refreshWorkbenchAgent(tenantId, activeWorkbenchId, address);
-      },
-      onOpenAgentSettings: (definitionId) => {
-        openWorkbenchSettings("agents", definitionId);
-      },
-    };
-  }, [catalogQuery.data, workbenchAgentsQuery.data, tenantId, activeWorkbenchId]);
-
-  const addressedMessageParts = useMemo(
-    () =>
-      lastHumanMessageParts(
-        mergePendingSends(
-          messagesState.kind === "ready" ? messagesState.items : [],
-          pendingSends,
-          currentUser?.principalId,
-        ),
-      ),
-    [messagesState, pendingSends, currentUser?.principalId],
-  );
-
-  // A settings URL for a workbench id that resolved workbenches don't contain
-  // (deleted, mistyped, cross-tenant) would otherwise leave the surface
-  // silently showing the ordinary chat view under a lying /settings URL —
-  // correct the route instead of no-opping.
-  useEffect(() => {
-    if (!settingsOpen) return;
-    if (workbenchesState.kind !== "ready") return;
-    if (activeWorkbenchId === null) return;
-    if (activeWorkbench !== undefined) return;
-    onSettingsOpenChange?.(false);
-  }, [
-    settingsOpen,
-    workbenchesState.kind,
-    activeWorkbenchId,
-    activeWorkbench,
-    onSettingsOpenChange,
-  ]);
-
-  // A routed id missing from the ready workbench list is NOT proof
-  // the room is gone — create→navigate races the React Query list cache, so
-  // a freshly created id is absent until refetch. Only an authoritative
-  // messages/workbench fetch 404 marks the room gone. While the list miss
-  // coincides with messages still loading, hold the loading treatment so we
-  // neither flash not-found nor paint Invite / composer / Untitled chrome.
-  const workbenchMissingFromList =
-    workbenchesState.kind === "ready" &&
-    activeWorkbenchId !== null &&
-    activeWorkbench === undefined;
-  const workbenchGone = messagesState.kind === "error" && messagesState.workbenchNotFound;
-  const awaitingWorkbenchEvidence =
-    workbenchMissingFromList && !workbenchGone && messagesState.kind !== "ready";
-
-  // Who's live in this workbench right now, beyond the static participants
-  // list — derived from this workbench's own `chat.presence`/
-  // `chat.presence.snapshot` stream events, never a second
-  // connection or an HTTP heartbeat poll. Display name and color are
-  // resolved client-side (the roster itself carries only ids) the same way
-  // `typingLabel` resolves a typing ping's principal.
-  const presenceMembers: readonly PresenceMember[] = useMemo(
-    () =>
-      presenceRoster.map((member) => {
-        return {
-          principalId: member.principalId,
-          displayName: typingLabel(
-            member.principalId,
-            activeWorkbench?.participants ?? [],
-            currentUser,
-          ),
-          avatarClassName: avatarClassForPrincipal(member.principalId),
-        };
-      }),
-    [presenceRoster, activeWorkbench?.participants, currentUser],
-  );
-
-  // Static member stack (square) vs live presence (round) — never one
-  // combined circular team stack.
-  const memberStack = buildMemberAvatarStack(
-    activeWorkbench?.participants ?? [],
-    agentDisplayNames,
-    currentUser,
-  );
-  const visibleMemberStack = memberStack.slice(0, TEAM_AVATAR_STACK_LIMIT);
-  const memberStackOverflow = memberStack.length - visibleMemberStack.length;
-  const visiblePresenceStack = presenceMembers.slice(0, TEAM_AVATAR_STACK_LIMIT);
-  const presenceStackOverflow = presenceMembers.length - visiblePresenceStack.length;
-
-  const showRoomChrome =
-    workbenchesState.kind === "ready" &&
-    activeWorkbenchId !== null &&
-    !workbenchGone &&
-    !awaitingWorkbenchEvidence;
-
-  const roomTitle = activeWorkbenchDisplayTitle || CHAT_STRINGS.unnamedWorkbench;
-
-  const headerActions = (
-    <>
-      {depth1Threads.length > 0 ? (
-        <details className="chat-threads-menu">
-          <summary className="chat-threads-menu-trigger">
-            {CHAT_STRINGS.threadsMenuCount(depth1Threads.length)}
-            <CaretDown className="size-3.5 opacity-70" />
-          </summary>
-          <div className="chat-threads-menu-panel" role="menu">
-            {depth1Threads.map((thread) => (
-              <div key={thread.id} className="chat-threads-menu-group">
-                <button
-                  type="button"
-                  role="menuitem"
-                  className="chat-threads-menu-item"
-                  onClick={() => {
-                    openThreadById(thread.id);
-                  }}
-                >
-                  {thread.title ??
-                    (thread.parentMessageId !== null
-                      ? `Reply · ${thread.parentMessageId.slice(0, 8)}`
-                      : "Thread")}
-                </button>
-                {(subThreadsByParentId.get(thread.id) ?? []).map((subThread) => (
-                  <button
-                    key={subThread.id}
-                    type="button"
-                    role="menuitem"
-                    className="chat-threads-menu-item chat-threads-menu-item-nested"
-                    onClick={() => {
-                      openThreadById(subThread.id);
-                    }}
-                  >
-                    {subThread.title ??
-                      (subThread.parentMessageId !== null
-                        ? `Fork · ${subThread.parentMessageId.slice(0, 8)}`
-                        : "Sub-thread")}
-                  </button>
-                ))}
-              </div>
-            ))}
-          </div>
-        </details>
-      ) : null}
-      {visibleMemberStack.length > 0 ? (
-        <div className="chat-member-stack" aria-label={CHAT_STRINGS.workbenchMembersLabel}>
-          {visibleMemberStack.map((entry) =>
-            entry.tone === "agent" ? (
-              <span
-                key={entry.key}
-                className="member-avatar !overflow-hidden !bg-transparent !p-0"
-                data-agent="true"
-                title={entry.label}
-              >
-                <CorbitAvatar size="sm" ariaLabel={entry.label} className="!size-full" />
-              </span>
-            ) : (
-              <span
-                key={entry.key}
-                className={`member-avatar ${entry.avatarClassName ?? ""}`}
-                title={entry.label}
-              >
-                {entry.initials}
-              </span>
-            ),
-          )}
-          {memberStackOverflow > 0 ? (
-            <span
-              className="chat-member-stack-overflow"
-              title={CHAT_STRINGS.teamStackOverflow(memberStackOverflow)}
-            >
-              +{memberStackOverflow}
-            </span>
-          ) : null}
-        </div>
-      ) : null}
-      {presenceMembers.length > 0 ? (
-        <div className="chat-presence-stack" aria-label={CHAT_STRINGS.workbenchPresenceLabel}>
-          {visiblePresenceStack.map((member) => (
-            <span
-              key={member.principalId}
-              className={`chat-presence-avatar ${member.avatarClassName}`}
-              title={member.displayName}
-            >
-              {member.displayName.slice(0, 1).toUpperCase()}
-            </span>
-          ))}
-          {presenceStackOverflow > 0 ? (
-            <span
-              className="chat-presence-stack-overflow"
-              title={CHAT_STRINGS.teamStackOverflow(presenceStackOverflow)}
-            >
-              +{presenceStackOverflow}
-            </span>
-          ) : null}
-        </div>
-      ) : null}
-      <div className="chat-workbench-settings-slot">
-        <Button
-          variant="ghost"
-          size="icon"
-          aria-label={CHAT_STRINGS.workbenchSettingsAction}
-          title={CHAT_STRINGS.workbenchSettingsAction}
-          onClick={() => openWorkbenchSettings()}
-        >
-          <SlidersHorizontal />
-        </Button>
-      </div>
-    </>
-  );
-
-  const threadBreadcrumb = inThreadView ? (
-    <nav className="chat-thread-breadcrumb" aria-label="Thread">
-      <button type="button" className="chat-thread-breadcrumb-link" onClick={closeThread}>
-        {roomTitle}
-      </button>
-      <span className="chat-thread-breadcrumb-sep" aria-hidden="true">
-        /
-      </span>
-      {openThreadParent !== undefined ? (
-        <>
-          <button
-            type="button"
-            className="chat-thread-breadcrumb-link"
-            onClick={() => {
-              openThreadById(openThreadParent.id);
-            }}
-          >
-            {openThreadParent.title ?? "Thread"}
-          </button>
-          <span className="chat-thread-breadcrumb-sep" aria-hidden="true">
-            /
-          </span>
-        </>
-      ) : null}
-      <span
-        className="chat-thread-breadcrumb-current"
-        {...(headerSlot === undefined ? { "aria-current": "page" as const } : {})}
-      >
-        {threadTitle}
-      </span>
-    </nav>
-  ) : null;
-
-  const roomChrome: ChatHeaderChrome = {
-    crumbs: [{ label: roomTitle }],
-    ...(inThreadView && threadBreadcrumb !== null
-      ? { subtitle: threadBreadcrumb }
-      : activeChatAgent !== undefined
-        ? { subtitle: <AgentBadge /> }
-        : {}),
-    actions: headerActions,
-  };
-
-  // The workbench header only exists once a workbench is active; the loading,
-  // error, and no-workbench states still carry the host's leading control (the
-  // shell's col2 toggle) so the sidebar stays reachable. When `headerSlot`
-  // owns the bar, that chrome lifts out of `.chat-workbench-header`.
-  const bareLeadingHeader =
-    headerSlot === undefined && headerLeading !== undefined && !showRoomChrome ? (
-      <div className="chat-workbench-header">{headerLeading}</div>
-    ) : null;
-
-  const stageHeader =
-    headerSlot !== undefined
-      ? headerSlot(showRoomChrome ? roomChrome : WORKBENCHES_LIST_CHROME)
-      : bareLeadingHeader;
-
-  if (settingsOpen && activeWorkbenchId !== null && activeWorkbench !== undefined) {
-    return (
-      <>
-        <div className="chat-workspace">
-          <WorkbenchSettingsSurface
-            key={activeWorkbenchId}
-            tenantId={tenantId}
-            workbenchId={activeWorkbenchId}
-            workbenchTitle={
-              displayWorkbenchTitle(activeWorkbench.title, activeWorkbench.id) ||
-              CHAT_STRINGS.unnamedWorkbench
-            }
-            section={settingsSection}
-            onSectionChange={(next) => onSettingsSectionChange?.(next)}
-            entityId={settingsEntityId}
-            {...(onSettingsEntityIdChange !== undefined
-              ? { onEntityIdChange: onSettingsEntityIdChange }
-              : {})}
-            onBack={() => onSettingsOpenChange?.(false)}
-            onSaved={refreshWorkbenchLists}
-            {...(currentUser !== undefined
-              ? { currentUserPrincipalId: currentUser.principalId }
-              : {})}
-          />
-        </div>
-      </>
-    );
-  }
-
-  return (
-    <>
-      <div className="chat-workspace">
-        <div className="chat-main">
-          {stageHeader}
-          {workbenchesState.kind === "loading" ? (
-            <WorkbenchLoadingState />
-          ) : workbenchesState.kind === "error" ? (
-            <EmptyState
-              icon={<WarningCircle />}
-              title={`Couldn't load ${CHAT_STRINGS.couldNotLoadWorkbenches}`}
-              description={workbenchesState.message}
-              action={
-                <Button variant="outline" onClick={() => void reloadWorkbenches()}>
-                  Try again
-                </Button>
-              }
-            />
-          ) : activeWorkbenchId === null ? (
-            <EmptyState
-              icon={<ChatCircle />}
-              title={CHAT_STRINGS.noChatSelectedTitle}
-              description={CHAT_STRINGS.noChatSelectedDescription}
-            />
-          ) : workbenchGone ? (
-            // Fail closed — never mount Invite / composer / room
-            // header over a missing or 404'd workbench. Recovery is the
-            // whole stage. Authoritative evidence only (messages 404), never
-            // a stale ready-list miss alone.
-            <EmptyState
-              icon={<WarningCircle />}
-              title={CHAT_STRINGS.workbenchNotFoundTitle}
-              description={CHAT_STRINGS.workbenchNotFoundDescription}
-              action={workbenchNotFoundRecoveryAction({
-                ...(onGoToMissionControl !== undefined ? { onGoToMissionControl } : {}),
-                ...(onNewWorkbench !== undefined ? { onNewWorkbench } : {}),
-                ...(onBackToWorkbenchList !== undefined ? { onBackToWorkbenchList } : {}),
-              })}
-            />
-          ) : awaitingWorkbenchEvidence ? (
-            // List cache is ready but lacks this id — wait for messages to
-            // prove the room exists (create→navigate) or 404 (true miss)
-            // before painting room chrome or the not-found empty state.
-            <WorkbenchLoadingState />
-          ) : (
-            <>
-              {headerSlot === undefined ? (
-                <div className="chat-workbench-header">
-                  {headerLeading}
-                  {inThreadView ? (
-                    threadBreadcrumb
-                  ) : (
-                    <div className="chat-workbench-identity">
-                      <h2 className="chat-workbench-title">{roomTitle}</h2>
-                      {activeChatAgent !== undefined ? <AgentBadge /> : null}
-                    </div>
-                  )}
-                  <div className="chat-workbench-actions">{headerActions}</div>
-                </div>
-              ) : null}
-              {messagesState.kind === "loading" ? (
-                <WorkbenchLoadingState />
-              ) : messagesState.kind === "error" ? (
-                <EmptyState
-                  icon={<WarningCircle />}
-                  title={`Couldn't load ${CHAT_STRINGS.couldNotLoadMessages}`}
-                  description={messagesState.message}
-                  action={
-                    messagesState.isUnauthorized ? (
-                      onSignIn !== undefined ? (
-                        <Button variant="outline" onClick={onSignIn}>
-                          Sign in
-                        </Button>
-                      ) : undefined
-                    ) : (
-                      <Button variant="outline" onClick={() => feed.refetchMessages()}>
-                        Try again
-                      </Button>
-                    )
-                  }
-                />
-              ) : (
-                <>
-                  {openThreadParent !== undefined ? (
-                    <div className="chat-thread-origin-banner">
-                      {CHAT_STRINGS.forkThreadOriginBanner}{" "}
-                      <button
-                        type="button"
-                        className="chat-thread-origin-banner-link"
-                        onClick={() => {
-                          openThreadById(openThreadParent.id);
-                        }}
-                      >
-                        {openThreadParent.title ?? "Thread"}
-                      </button>
-                    </div>
-                  ) : null}
-                  <WorkbenchTimeline
-                    settingUpAgent={
-                      activeWorkbench?.kind === "chat" &&
-                      typeof activeWorkbench.definitionId === "string" &&
-                      !(activeWorkbench.participants ?? []).some((participant) =>
-                        isAgentAddress(participant.address),
-                      )
-                    }
-                    items={appendReplyTimedOutNotice(
-                      mergeStreamingReply(
-                        mergePendingSends(
-                          messagesState.items,
-                          pendingSends,
-                          currentUser?.principalId,
-                        ),
-                        streamingReply,
-                        activeWorkbench?.participants ?? [],
-                      ),
-                      replyTimedOutRefId,
-                      activeWorkbench?.participants ?? [],
-                    )}
-                    participants={activeWorkbench?.participants ?? []}
-                    {...(currentUser !== undefined ? { currentUser } : {})}
-                    agentDisplayNames={agentDisplayNames}
-                    threadMetaByMessageId={threadMetaByMessageId}
-                    threadAffordanceMode={inThreadView ? "fork" : "reply"}
-                    onOpenThread={inThreadView ? forkMessage : openThreadForMessage}
-                    onEditMessage={(messageId) => {
-                      if (messagesState.kind !== "ready") return;
-                      const item = messagesState.items.find((message) => message.id === messageId);
-                      if (item === undefined) return;
-                      composerRef.current?.setText(messageText(item));
-                    }}
-                    {...(onOpenProfile !== undefined ? { onOpenProfile } : {})}
-                    {...(onOpenArtifact !== undefined ? { onOpenArtifact } : {})}
-                    {...(onOpenArtifactInLibrary !== undefined ? { onOpenArtifactInLibrary } : {})}
-                    {...(onFixConnection !== undefined ? { onFixConnection } : {})}
-                    {...(approvalActions !== undefined ? { approvalActions } : {})}
-                    {...(connectServiceActions !== undefined ? { connectServiceActions } : {})}
-                    onRetryFailedTurn={handleRetryFailedTurn}
-                    failedTurnRecovery={failedTurnRecovery}
-                    pendingActions={{
-                      onRetry: retryPendingSend,
-                      onDiscard: discardPendingSend,
-                    }}
-                    {...(restoredScrollSnapshot !== undefined
-                      ? { scrollRestore: restoredScrollSnapshot }
-                      : {})}
-                    onScrollSnapshot={handleScrollSnapshot}
-                    footer={
-                      typingState !== null ? (
-                        <TypingIndicator
-                          label={typingLabel(
-                            typingState.principalId,
-                            activeWorkbench?.participants ?? [],
-                            currentUser,
-                          )}
-                        />
-                      ) : (
-                        <AgentTypingIndicator
-                          names={typingAgentNames(
-                            streamingReply,
-                            activeWorkbench?.participants ?? [],
-                            addressedMessageParts,
-                            agentDisplayNames,
-                          )}
-                        />
-                      )
-                    }
-                  />
-                  <TurnActivityStrip activity={turnActivity} />
-                  <div className="chat-composer-stack">
-                    {resumeFailedRefId !== null ? (
-                      <ResumeFailedBanner refId={resumeFailedRefId} onRetry={handleRetryResume} />
-                    ) : null}
-                    {hasUsableModel === false && hasAgentParticipant ? (
-                      <NoUsableModelBanner onConnectModel={() => onConnectModel?.()} />
-                    ) : null}
-                    <Composer
-                      ref={composerRef}
-                      agents={mentionCandidatesFromParticipants(
-                        activeWorkbench?.participants ?? [],
-                        agentDisplayNames,
-                      )}
-                      placeholder={composerPlaceholderFor(activeWorkbench)}
-                      onSend={handleSend}
-                      running={isAwaitingReply(streamingReply)}
-                      onStop={handleStopTurn}
-                    />
-                  </div>
-                </>
-              )}
-            </>
-          )}
-        </div>
-      </div>
-    </>
-  );
-}
-
-function ChatWorkspaceFrame({ children }: { readonly children: ReactNode }) {
-  return <div className="chat-workspace-frame">{children}</div>;
-}
-
-function withListHeader(
-  headerSlot: ((chrome: ChatHeaderChrome) => ReactNode) | undefined,
-  children: ReactNode,
-): ReactNode {
-  if (headerSlot === undefined) {
-    return <ChatWorkspaceFrame>{children}</ChatWorkspaceFrame>;
-  }
-  return (
-    <>
-      {headerSlot(WORKBENCHES_LIST_CHROME)}
-      <ChatWorkspaceFrame>{children}</ChatWorkspaceFrame>
-    </>
-  );
-}
-
-export function ChatWorkspace({
-  tenant,
-  workbenchId = null,
-  onWorkbenchChange,
-  currentUser,
-  onOpenProfile,
-  settingsOpen,
-  onSettingsOpenChange,
-  settingsSection,
-  onSettingsSectionChange,
-  settingsEntityId,
-  onSettingsEntityIdChange,
-  onOpenArtifact,
-  onOpenArtifactInLibrary,
-  onFixConnection,
-  approvalActions,
-  connectServiceActions,
-  headerLeading,
-  headerSlot,
-  registerComposerInsert,
-  onWorkbenchNotFound,
-  onBackToWorkbenchList,
-  onGoToMissionControl,
-  onNewWorkbench,
-  onSignIn,
-  hasUsableModel,
-  onConnectModel,
-}: {
-  readonly tenant: TenantResolution;
-  /** Controlled active workbench (e.g. from the app's URL); null = pick the first. */
-  readonly workbenchId?: string | null;
-  /** Fired when the user selects a workbench, so the app can reflect it in the URL. */
-  readonly onWorkbenchChange?: (workbenchId: string) => void;
-  /**
-   * The signed-in account, so its own messages render as "You" (or its
-   * name) instead of matching no participant and falling back to
-   * "Member". Host-supplied, the same way `tenant` is — this package
-   * never resolves a session itself.
-   */
-  readonly currentUser?: CurrentUser;
-  /** Open a member/agent ProfileCard in the host canvas (shell mock § Profile). */
-  readonly onOpenProfile?: (subject: ProfileSubject) => void;
-  /** Whether the routed workbench's settings surface should replace the
-   * conversation stage — host-controlled from the URL (`/w/:id/settings`). */
-  readonly settingsOpen?: boolean;
-  /** Fired when the settings surface should open or close, so the host can
-   * reflect it in the URL — see `ChatWorkspaceInner`'s prop of the same
-   * name for the `section` argument's contract. */
-  readonly onSettingsOpenChange?: (
-    open: boolean,
-    section?: WorkbenchSettingsSectionId,
-    entityId?: string,
-  ) => void;
-  /** Which workbench settings tab is active — host-controlled from the URL
-   * (`/w/:id/settings/:section`). */
-  readonly settingsSection?: WorkbenchSettingsSectionId;
-  /** Fired when the user switches tabs while the settings surface is
-   * already open, so the host can reflect it in the URL. */
-  readonly onSettingsSectionChange?: (section: WorkbenchSettingsSectionId) => void;
-  /** Section sub-selection — host-controlled from the URL
-   * (`/w/:id/settings/:section/:entityId`). */
-  readonly settingsEntityId?: string | null;
-  /** Fired when a settings section opens or closes its own detail, so the
-   * host can deepen or clear the entity segment in the URL. */
-  readonly onSettingsEntityIdChange?: (entityId: string | null) => void;
-  /** Open a message's artifact chip — see `WorkbenchTimeline`'s `onOpenArtifact`. */
-  readonly onOpenArtifact?: (part: Part & { kind: "file" }) => void;
-  /** The chip's "Open in Library" affordance — see `WorkbenchTimeline`'s
-   * `onOpenArtifactInLibrary`. */
-  readonly onOpenArtifactInLibrary?: (part: Part & { kind: "file" }) => void;
-  /** The classified-inference-failure text bubble's "Fix this connection"
-   * action — see `WorkbenchTimeline`'s `onFixConnection`. */
-  readonly onFixConnection?: () => void;
-  /** The approve block's live round-trip — see `WorkbenchTimeline`'s
-   * `approvalActions`. */
-  readonly approvalActions?: ApprovalActions;
-  /** Host round-trip for the generic "connect-service" card. Undefined
-   * renders every connect-service card in its disconnected framing. */
-  readonly connectServiceActions?: ConnectServiceActions;
-  /** Host-supplied control rendered first in the workbench header — the
-   * shell's single col2 toggle, so chat carries the same top-bar chrome as
-   * every other stage surface. Unused when `headerSlot` owns the bar. */
-  readonly headerLeading?: ReactNode;
-  /** Host-owned stage bar. When set, identity and primary actions render
-   * through this slot (`StageTopBar`'s crumbs / subtitle / actions) instead
-   * of `.chat-workbench-header`. */
-  readonly headerSlot?: (chrome: ChatHeaderChrome) => ReactNode;
-  /** See `ChatWorkspaceInner`'s prop of the same name. */
-  readonly registerComposerInsert?: (insert: ((text: string) => void) | null) => void;
-  /** See `ChatWorkspaceInner`'s prop of the same name. */
-  readonly onWorkbenchNotFound?: (workbenchId: string) => void;
-  /** See `ChatWorkspaceInner`'s prop of the same name. */
-  readonly onBackToWorkbenchList?: () => void;
-  /** See `ChatWorkspaceInner`'s prop of the same name. */
-  readonly onGoToMissionControl?: () => void;
-  /** See `ChatWorkspaceInner`'s prop of the same name. */
-  readonly onNewWorkbench?: () => void;
-  /** See `ChatWorkspaceInner`'s prop of the same name. */
-  readonly onSignIn?: () => void;
-  /** See `ChatWorkspaceInner`'s prop of the same name. */
-  readonly hasUsableModel?: boolean;
-  /** See `ChatWorkspaceInner`'s prop of the same name. */
-  readonly onConnectModel?: () => void;
-}) {
-  switch (tenant.kind) {
-    case "ready":
-      // Remount on tenant switch so prior-tenant state cannot leak.
-      return (
-        <ChatWorkspaceInner
-          key={tenant.tenantId}
-          tenantId={tenant.tenantId}
-          workbenchId={workbenchId}
-          {...(onWorkbenchChange !== undefined ? { onWorkbenchChange } : {})}
-          {...(currentUser !== undefined ? { currentUser } : {})}
-          {...(onOpenProfile !== undefined ? { onOpenProfile } : {})}
-          {...(settingsOpen !== undefined ? { settingsOpen } : {})}
-          {...(onSettingsOpenChange !== undefined ? { onSettingsOpenChange } : {})}
-          {...(settingsSection !== undefined ? { settingsSection } : {})}
-          {...(onSettingsSectionChange !== undefined ? { onSettingsSectionChange } : {})}
-          {...(settingsEntityId !== undefined ? { settingsEntityId } : {})}
-          {...(onSettingsEntityIdChange !== undefined ? { onSettingsEntityIdChange } : {})}
-          {...(approvalActions !== undefined ? { approvalActions } : {})}
-          {...(connectServiceActions !== undefined ? { connectServiceActions } : {})}
-          {...(onOpenArtifact !== undefined ? { onOpenArtifact } : {})}
-          {...(onOpenArtifactInLibrary !== undefined ? { onOpenArtifactInLibrary } : {})}
-          {...(onFixConnection !== undefined ? { onFixConnection } : {})}
-          {...(headerLeading !== undefined ? { headerLeading } : {})}
-          {...(headerSlot !== undefined ? { headerSlot } : {})}
-          {...(registerComposerInsert !== undefined ? { registerComposerInsert } : {})}
-          {...(onWorkbenchNotFound !== undefined ? { onWorkbenchNotFound } : {})}
-          {...(onBackToWorkbenchList !== undefined ? { onBackToWorkbenchList } : {})}
-          {...(onGoToMissionControl !== undefined ? { onGoToMissionControl } : {})}
-          {...(onNewWorkbench !== undefined ? { onNewWorkbench } : {})}
-          {...(onSignIn !== undefined ? { onSignIn } : {})}
-          {...(hasUsableModel !== undefined ? { hasUsableModel } : {})}
-          {...(onConnectModel !== undefined ? { onConnectModel } : {})}
-        />
-      );
-    case "empty":
-      return withListHeader(
-        headerSlot,
-        <EmptyState
-          icon={<ChatCircle />}
-          title="No workbench yet"
-          description="Create or join a workbench before chatting."
-        />,
-      );
-    case "unauthenticated":
-      return withListHeader(
-        headerSlot,
-        <EmptyState
-          icon={<ChatCircle />}
-          title="Sign in to continue"
-          description="Your conversations live on a workbench — sign in to open them."
-        />,
-      );
-    case "error":
-      return withListHeader(
-        headerSlot,
-        <EmptyState
-          icon={<WarningCircle />}
-          title="Couldn't open this workbench"
-          description={tenant.message}
-        />,
-      );
-    case "loading":
-      return withListHeader(headerSlot, <WorkbenchLoadingState />);
-  }
-}
diff --git a/apps/web/src/chat/composer-synchronous-double-send.test.tsx b/apps/web/src/chat/composer-synchronous-double-send.test.tsx
deleted file mode 100644
index 9355d33f4..000000000
--- a/apps/web/src/chat/composer-synchronous-double-send.test.tsx
+++ /dev/null
@@ -1,98 +0,0 @@
-// The composer's send guard used to test the `sending` *state*
-// variable, which `performSend` only sets after the click/keydown handler
-// that started it has already returned. Two triggers landing in the same
-// synchronous tick (e.g. a stray double dispatch of the send action) both
-// read `sending === false` and both post — this proves a second trigger in
-// the same tick is turned away regardless of state timing.
-
-import { afterEach, describe, expect, test } from "bun:test";
-import { act, createElement, createRef } from "react";
-import { createRoot } from "react-dom/client";
-import type { Root } from "react-dom/client";
-
-import { Composer } from "./composer";
-import type { ComposerHandle, ComposerSendPayload } from "./composer";
-
-let container: HTMLDivElement | null = null;
-let root: Root | null = null;
-
-afterEach(() => {
-  if (root !== null) {
-    act(() => root?.unmount());
-    root = null;
-  }
-  if (container !== null) {
-    container.remove();
-    container = null;
-  }
-});
-
-const settle = () => act(() => new Promise((resolve) => setTimeout(resolve, 0)));
-
-function mount(onSend: (payload: ComposerSendPayload) => Promise<boolean>) {
-  container = document.createElement("div");
-  document.body.appendChild(container);
-  root = createRoot(container);
-  const ref = createRef<ComposerHandle>();
-  act(() => {
-    root?.render(
-      createElement(Composer, {
-        ref,
-        agents: [],
-        onSend,
-      }),
-    );
-  });
-  return container;
-}
-
-function textarea(): HTMLTextAreaElement {
-  const element = container?.querySelector("textarea");
-  if (element === null || element === undefined) {
-    throw new Error("composer textarea not found");
-  }
-  return element;
-}
-
-function typeInto(element: HTMLTextAreaElement, text: string) {
-  const setter = Object.getOwnPropertyDescriptor(
-    globalThis.HTMLTextAreaElement.prototype,
-    "value",
-  )?.set;
-  act(() => {
-    setter?.call(element, text);
-    element.dispatchEvent(new Event("input", { bubbles: true }));
-  });
-}
-
-function sendButton(): HTMLButtonElement {
-  const button = container?.querySelector<HTMLButtonElement>('[aria-label^="Send"]');
-  if (button === null || button === undefined) {
-    throw new Error("send button not found");
-  }
-  return button;
-}
-
-describe("Composer synchronous double-send guard", () => {
-  test("two clicks in the same tick post exactly one send", async () => {
-    let sendCount = 0;
-    const payloads: ComposerSendPayload[] = [];
-    mount((payload) => {
-      sendCount += 1;
-      payloads.push(payload);
-      return Promise.resolve(true);
-    });
-
-    typeInto(textarea(), "hello there");
-    await settle();
-
-    act(() => {
-      sendButton().click();
-      sendButton().click();
-    });
-    await settle();
-
-    expect(sendCount).toBe(1);
-    expect(payloads).toEqual([{ text: "hello there", attachments: [] }]);
-  });
-});
diff --git a/apps/web/src/chat/composer.test.tsx b/apps/web/src/chat/composer.test.tsx
deleted file mode 100644
index 5a487308f..000000000
--- a/apps/web/src/chat/composer.test.tsx
+++ /dev/null
@@ -1,848 +0,0 @@
-import { afterEach, describe, expect, spyOn, test } from "bun:test";
-import { act, createElement, createRef } from "react";
-import { createRoot } from "react-dom/client";
-import type { Root } from "react-dom/client";
-import * as errorSink from "@corbits/error-sink";
-
-import { Composer } from "./composer";
-import type { ComposerHandle, ComposerSendPayload } from "./composer";
-
-// The in-flight send contract survives the icon-only UI: its accessible name
-// announces progress and the action remains unavailable until sending ends.
-let container: HTMLDivElement | null = null;
-let root: Root | null = null;
-
-afterEach(() => {
-  if (root !== null) {
-    act(() => root?.unmount());
-    root = null;
-  }
-  if (container !== null) {
-    container.remove();
-    container = null;
-  }
-});
-
-const settle = () => act(() => new Promise((resolve) => setTimeout(resolve, 0)));
-
-function mount(onSend: () => Promise<boolean>) {
-  container = document.createElement("div");
-  document.body.appendChild(container);
-  root = createRoot(container);
-  const ref = createRef<ComposerHandle>();
-  act(() => {
-    root?.render(
-      createElement(Composer, {
-        ref,
-        agents: [],
-        onSend,
-      }),
-    );
-  });
-  return container;
-}
-
-function sendButton(): HTMLButtonElement {
-  const button = container?.querySelector<HTMLButtonElement>('[aria-label^="Send"]');
-  if (button === null || button === undefined) {
-    throw new Error("send button not found");
-  }
-  return button;
-}
-
-function keyboardHint(): Element | null {
-  return container?.querySelector(".chat-composer-keyboard-hint") ?? null;
-}
-
-describe("Composer send button", () => {
-  test("updates its accessible label and stays disabled while sending", async () => {
-    let resolveSend: (value: boolean) => void = () => undefined;
-    const onSend = () =>
-      new Promise<boolean>((resolve) => {
-        resolveSend = resolve;
-      });
-    mount(onSend);
-
-    const textarea = container?.querySelector("textarea");
-    if (textarea === null || textarea === undefined) {
-      throw new Error("composer textarea not found");
-    }
-    act(() => {
-      const setter = Object.getOwnPropertyDescriptor(
-        globalThis.HTMLTextAreaElement.prototype,
-        "value",
-      )?.set;
-      setter?.call(textarea, "hello there");
-      textarea.dispatchEvent(new Event("input", { bubbles: true }));
-    });
-    await settle();
-
-    expect(sendButton().getAttribute("aria-label")).toBe("Send");
-
-    act(() => {
-      sendButton().click();
-    });
-    await settle();
-
-    expect(sendButton().getAttribute("aria-label")).toBe("Sending…");
-    expect(sendButton().hasAttribute("disabled")).toBe(true);
-
-    await act(async () => {
-      resolveSend(true);
-      await Promise.resolve();
-      await Promise.resolve();
-    });
-
-    expect(sendButton().getAttribute("aria-label")).toBe("Send");
-  });
-});
-
-test("labels the icon-only attachment action in the composer rail", () => {
-  mount(() => Promise.resolve(true));
-
-  expect(container?.querySelector('[aria-label="Attach files"]')?.textContent).toBe("");
-});
-
-function textarea(): HTMLTextAreaElement {
-  const element = container?.querySelector("textarea");
-  if (element === null || element === undefined) {
-    throw new Error("composer textarea not found");
-  }
-  return element;
-}
-
-function typeInto(element: HTMLTextAreaElement, text: string) {
-  const setter = Object.getOwnPropertyDescriptor(
-    globalThis.HTMLTextAreaElement.prototype,
-    "value",
-  )?.set;
-  act(() => {
-    setter?.call(element, text);
-    element.dispatchEvent(new Event("input", { bubbles: true }));
-  });
-}
-
-function mountWithMentions(onSend: (payload: ComposerSendPayload) => Promise<boolean>) {
-  container = document.createElement("div");
-  document.body.appendChild(container);
-  root = createRoot(container);
-  const ref = createRef<ComposerHandle>();
-  act(() => {
-    root?.render(
-      createElement(Composer, {
-        ref,
-        agents: [{ id: "researcher@agents.example", handle: "researcher", label: "Researcher" }],
-        onSend,
-      }),
-    );
-  });
-  return container;
-}
-
-describe("Composer keyboard hint", () => {
-  test("uses the existing action rail and appears only for a focused non-empty draft", async () => {
-    mount(() => Promise.resolve(true));
-    expect(keyboardHint()).not.toBeNull();
-    expect(keyboardHint()?.getAttribute("data-visible")).toBe("false");
-    expect(keyboardHint()?.getAttribute("aria-hidden")).toBe("true");
-
-    act(() => {
-      textarea().focus();
-    });
-    typeInto(textarea(), "hello");
-    await settle();
-
-    expect(keyboardHint()?.getAttribute("data-visible")).toBe("true");
-    expect(keyboardHint()?.getAttribute("aria-hidden")).toBe("false");
-    expect(keyboardHint()?.textContent).toBe("Enter to send");
-    expect(container?.querySelectorAll(".chat-composer-actions button").length).toBe(2);
-    expect(container?.querySelector(".chat-composer-row > textarea")).toBe(textarea());
-  });
-
-  test("hides when the focused draft is cleared", async () => {
-    mount(() => Promise.resolve(true));
-    act(() => {
-      textarea().focus();
-    });
-    typeInto(textarea(), "hello");
-    await settle();
-    expect(keyboardHint()?.getAttribute("data-visible")).toBe("true");
-
-    typeInto(textarea(), "");
-    await settle();
-    expect(keyboardHint()?.getAttribute("data-visible")).toBe("false");
-    expect(keyboardHint()?.getAttribute("aria-hidden")).toBe("true");
-  });
-});
-
-describe("Composer growth containment", () => {
-  test("the textarea carries the max-height/overflow class and keeps applying its measured inline height", async () => {
-    mount(() => Promise.resolve(true));
-    expect(textarea().className).toContain("chat-composer-input");
-
-    typeInto(textarea(), "line one\nline two\nline three");
-    await settle();
-    // The auto-grow effect still measures and writes an inline height on
-    // every change — the CSS transition only smooths that write, it does
-    // not replace it.
-    expect(textarea().style.height.endsWith("px")).toBe(true);
-  });
-});
-
-describe("Composer popover entrance", () => {
-  test("the mention popover carries the entrance class", async () => {
-    mountWithMentions(() => Promise.resolve(true));
-    typeInto(textarea(), "@");
-    await settle();
-    const popover = container?.querySelector(".chat-mention-popover");
-    expect(popover?.classList.contains("chat-popover-enter")).toBe(true);
-  });
-});
-
-describe("Composer hit targets", () => {
-  test("attach and send buttons carry the extended-hit-area class", () => {
-    mount(() => Promise.resolve(true));
-    const buttons = container?.querySelectorAll(".chat-composer-icon-button");
-    expect(buttons?.length).toBe(2);
-  });
-});
-
-describe("ComposerHandle.setText", () => {
-  test("replaces the existing draft and focuses with the caret at the end", async () => {
-    container = document.createElement("div");
-    document.body.appendChild(container);
-    root = createRoot(container);
-    const ref = createRef<ComposerHandle>();
-    act(() => {
-      root?.render(
-        createElement(Composer, {
-          ref,
-          agents: [],
-          onSend: () => Promise.resolve(true),
-        }),
-      );
-    });
-
-    typeInto(textarea(), "unsent draft");
-    await settle();
-    expect(textarea().value).toBe("unsent draft");
-
-    await act(async () => {
-      ref.current?.setText("previous prompt");
-      await new Promise<void>((resolve) => {
-        requestAnimationFrame(() => resolve());
-      });
-    });
-
-    expect(textarea().value).toBe("previous prompt");
-    expect(document.activeElement).toBe(textarea());
-    expect(textarea().selectionStart).toBe("previous prompt".length);
-    expect(textarea().selectionEnd).toBe("previous prompt".length);
-  });
-
-  test("Enter after setText of an @handle prompt sends instead of opening mention", async () => {
-    container = document.createElement("div");
-    document.body.appendChild(container);
-    root = createRoot(container);
-    const ref = createRef<ComposerHandle>();
-    const sent: ComposerSendPayload[] = [];
-    act(() => {
-      root?.render(
-        createElement(Composer, {
-          ref,
-          agents: [{ id: "researcher@agents.example", handle: "researcher", label: "Researcher" }],
-          onSend: (payload) => {
-            sent.push(payload);
-            return Promise.resolve(true);
-          },
-        }),
-      );
-    });
-
-    await act(async () => {
-      ref.current?.setText("@researcher");
-      await new Promise<void>((resolve) => {
-        requestAnimationFrame(() => resolve());
-      });
-    });
-    await settle();
-
-    expect(container?.querySelector(".chat-mention-popover")).toBeNull();
-
-    act(() => {
-      textarea().dispatchEvent(
-        new KeyboardEvent("keydown", {
-          key: "Enter",
-          bubbles: true,
-          cancelable: true,
-        }),
-      );
-    });
-    await settle();
-
-    expect(sent).toEqual([{ text: "@researcher", attachments: [] }]);
-  });
-
-  test("Send after setText does not carry leftover attachments", async () => {
-    const sent: ComposerSendPayload[] = [];
-    const ref = createRef<ComposerHandle>();
-    container = document.createElement("div");
-    document.body.appendChild(container);
-    root = createRoot(container);
-    act(() => {
-      root?.render(
-        createElement(Composer, {
-          ref,
-          agents: [],
-          onSend: (payload) => {
-            sent.push(payload);
-            return Promise.resolve(true);
-          },
-        }),
-      );
-    });
-
-    const fileInput = container.querySelector<HTMLInputElement>(".chat-composer-file-input");
-    if (fileInput === null) throw new Error("file input not found");
-
-    const file = new File(["hello"], "notes.txt", { type: "text/plain" });
-    Object.defineProperty(fileInput, "files", {
-      configurable: true,
-      value: {
-        0: file,
-        length: 1,
-        item: (index: number) => (index === 0 ? file : null),
-        [Symbol.iterator]: function* () {
-          yield file;
-        },
-      },
-    });
-    act(() => {
-      fileInput.dispatchEvent(new Event("change", { bubbles: true }));
-    });
-    await settle();
-    await settle();
-    expect(container.querySelector(".chat-composer-attachments")).not.toBeNull();
-
-    await act(async () => {
-      ref.current?.setText("copied prompt");
-      await new Promise<void>((resolve) => {
-        requestAnimationFrame(() => resolve());
-      });
-    });
-    await settle();
-
-    expect(container.querySelector(".chat-composer-attachments")).toBeNull();
-
-    act(() => {
-      sendButton().click();
-    });
-    await settle();
-
-    expect(sent).toEqual([{ text: "copied prompt", attachments: [] }]);
-  });
-});
-
-// The composer's Stop affordance. `handleStop` guards against a
-// double-click and re-enables itself once the host reports the turn is
-// no longer running -- but a REJECTED stop request must also re-enable
-// it, or a genuinely failed cancel (not a slow one) leaves the person
-// with a permanently disabled button and no way to retry for the rest
-// of that turn's life.
-function stopButton(): HTMLButtonElement {
-  const button = container?.querySelector<HTMLButtonElement>('[aria-label="Stop"]');
-  if (button === null || button === undefined) {
-    throw new Error("stop button not found");
-  }
-  return button;
-}
-
-function mountStoppable(
-  running: boolean,
-  onStop: () => void | Promise<unknown>,
-  onSend: (payload: ComposerSendPayload) => Promise<boolean> = () => Promise.resolve(true),
-) {
-  container = document.createElement("div");
-  document.body.appendChild(container);
-  root = createRoot(container);
-  act(() => {
-    root?.render(
-      createElement(Composer, {
-        agents: [],
-        onSend,
-        running,
-        onStop,
-      }),
-    );
-  });
-  return {
-    container,
-    rerender: (nextRunning: boolean) => {
-      act(() => {
-        root?.render(
-          createElement(Composer, {
-            agents: [],
-            onSend,
-            running: nextRunning,
-            onStop,
-          }),
-        );
-      });
-    },
-  };
-}
-
-describe("Composer stop affordance", () => {
-  test("keeps Stop and Send together in the right-aligned action group", () => {
-    mountStoppable(true, () => undefined);
-
-    const actions = container?.querySelector(".chat-composer-actions");
-    const submitActions = stopButton().parentElement;
-    expect(actions?.children).toHaveLength(3);
-    expect(submitActions?.classList.contains("chat-composer-submit-actions")).toBe(true);
-    expect(submitActions?.children).toHaveLength(2);
-    expect(submitActions?.lastElementChild).toBe(sendButton());
-    expect(actions?.lastElementChild).toBe(submitActions);
-  });
-
-  test("gives Stop and Send distinct accessible names while both are visible", () => {
-    mountStoppable(true, () => undefined);
-
-    expect(stopButton().getAttribute("aria-label")).toBe("Stop");
-    expect(sendButton().getAttribute("aria-label")).toBe("Send");
-  });
-
-  test("keeps queued sends available while Stop is visible", async () => {
-    const sent: ComposerSendPayload[] = [];
-    mountStoppable(
-      true,
-      () => undefined,
-      (payload) => {
-        sent.push(payload);
-        return Promise.resolve(true);
-      },
-    );
-
-    typeInto(textarea(), "follow-up");
-    await settle();
-
-    expect(sendButton().hasAttribute("disabled")).toBe(false);
-    act(() => {
-      sendButton().click();
-    });
-    await settle();
-
-    expect(sent).toEqual([{ text: "follow-up", attachments: [] }]);
-  });
-
-  test("renders no Stop button when no turn is running", () => {
-    mountStoppable(false, () => undefined);
-    expect(container?.querySelector('[aria-label="Stop"]')).toBeNull();
-  });
-
-  test("clicking Stop calls onStop and disables the button against a double-click", async () => {
-    let calls = 0;
-    mountStoppable(true, () => {
-      calls += 1;
-    });
-
-    expect(stopButton().hasAttribute("disabled")).toBe(false);
-    act(() => {
-      stopButton().click();
-    });
-    await settle();
-
-    expect(calls).toBe(1);
-    expect(stopButton().hasAttribute("disabled")).toBe(true);
-
-    act(() => {
-      stopButton().click();
-    });
-    await settle();
-    expect(calls).toBe(1);
-  });
-
-  test("the button re-enables once the host reports the turn is no longer running", async () => {
-    const { rerender } = mountStoppable(true, () => undefined);
-    act(() => {
-      stopButton().click();
-    });
-    await settle();
-    expect(stopButton().hasAttribute("disabled")).toBe(true);
-
-    rerender(false);
-    expect(container?.querySelector('[aria-label="Stop"]')).toBeNull();
-  });
-
-  test("a stop request that REJECTS re-enables the button instead of leaving it stuck", async () => {
-    let reject: (err: unknown) => void = () => undefined;
-    mountStoppable(
-      true,
-      () =>
-        new Promise((_resolve, rej) => {
-          reject = rej;
-        }),
-    );
-
-    act(() => {
-      stopButton().click();
-    });
-    await settle();
-    expect(stopButton().hasAttribute("disabled")).toBe(true);
-
-    await act(async () => {
-      reject(new Error("network error"));
-      await Promise.resolve();
-      await Promise.resolve();
-    });
-
-    // The turn is still running (the cancel request itself failed, not
-    // the turn) -- the button must come back so the user can try again.
-    expect(stopButton().hasAttribute("disabled")).toBe(false);
-  });
-});
-
-describe("Composer dictate", () => {
-  const recognitions: FakeSpeechRecognition[] = [];
-
-  class FakeSpeechRecognition {
-    continuous = false;
-    interimResults = false;
-    onresult: ((event: { results: FakeSpeechResult[] }) => void) | null = null;
-    onerror: ((event: unknown) => void) | null = null;
-    onend: (() => void) | null = null;
-    started = false;
-    resultOnStop: readonly { isFinal: boolean; transcript: string }[] | null = null;
-
-    constructor() {
-      recognitions.push(this);
-    }
-
-    start() {
-      this.started = true;
-    }
-
-    stop() {
-      this.started = false;
-      if (this.resultOnStop !== null) {
-        this.emit(this.resultOnStop);
-        this.resultOnStop = null;
-      }
-      this.onend?.();
-    }
-
-    abort() {
-      this.started = false;
-      this.onend?.();
-    }
-
-    emit(segments: readonly { isFinal: boolean; transcript: string }[]) {
-      const results = segments.map((segment) => ({
-        isFinal: segment.isFinal,
-        length: 1,
-        0: { transcript: segment.transcript },
-      }));
-      this.onresult?.({ results });
-    }
-  }
-
-  type FakeSpeechResult = {
-    readonly isFinal: boolean;
-    readonly length: number;
-    readonly 0: { readonly transcript: string };
-  };
-
-  function installSpeechRecognition() {
-    Object.defineProperty(window, "SpeechRecognition", {
-      configurable: true,
-      writable: true,
-      value: FakeSpeechRecognition,
-    });
-  }
-
-  afterEach(() => {
-    recognitions.length = 0;
-    Reflect.deleteProperty(window, "SpeechRecognition");
-  });
-
-  test("hides the dictate control when speech recognition is unavailable", () => {
-    mount(() => Promise.resolve(true));
-    expect(container?.querySelector('[aria-label="Dictate"]')).toBeNull();
-  });
-
-  test("starts recognition, inserts a transcript on a word boundary, and stops", async () => {
-    installSpeechRecognition();
-    mount(() => Promise.resolve(true));
-    typeInto(textarea(), "hello");
-    textarea().setSelectionRange(5, 5);
-    await settle();
-
-    const dictate = container?.querySelector<HTMLButtonElement>('[aria-label="Dictate"]');
-    if (dictate === null || dictate === undefined) {
-      throw new Error("dictate button not found");
-    }
-
-    act(() => {
-      dictate.click();
-    });
-    await settle();
-
-    expect(recognitions.at(-1)?.started).toBe(true);
-    expect(recognitions.at(-1)?.continuous).toBe(true);
-    expect(recognitions.at(-1)?.interimResults).toBe(true);
-    expect(dictate.getAttribute("aria-label")).toBe("Stop dictating");
-    expect(dictate.getAttribute("aria-pressed")).toBe("true");
-    expect(dictate.getAttribute("data-listening")).toBe("true");
-
-    act(() => {
-      recognitions.at(-1)?.emit([{ isFinal: true, transcript: "world" }]);
-    });
-    await settle();
-
-    expect(textarea().value).toBe("hello world");
-
-    act(() => {
-      dictate.click();
-    });
-    await settle();
-
-    expect(recognitions.at(-1)?.started).toBe(false);
-    const idle = container?.querySelector<HTMLButtonElement>('[aria-label="Dictate"]');
-    expect(idle?.getAttribute("aria-pressed")).toBe("false");
-    expect(idle?.getAttribute("data-listening")).toBe("false");
-  });
-
-  test("user Stop flushes a late final result into the draft", async () => {
-    installSpeechRecognition();
-    mount(() => Promise.resolve(true));
-    typeInto(textarea(), "hello");
-    textarea().setSelectionRange(5, 5);
-    await settle();
-
-    const dictate = container?.querySelector<HTMLButtonElement>('[aria-label="Dictate"]');
-    if (dictate === null || dictate === undefined) {
-      throw new Error("dictate button not found");
-    }
-
-    act(() => {
-      dictate.click();
-    });
-    await settle();
-
-    const rec = recognitions.at(-1);
-    if (rec === undefined) {
-      throw new Error("speech recognition was not constructed");
-    }
-    rec.resultOnStop = [{ isFinal: true, transcript: "world" }];
-
-    act(() => {
-      dictate.click();
-    });
-    await settle();
-
-    expect(textarea().value).toBe("hello world");
-    expect(rec.started).toBe(false);
-  });
-
-  test("send while listening does not restore the draft from a late final result", async () => {
-    installSpeechRecognition();
-    const sent: ComposerSendPayload[] = [];
-    container = document.createElement("div");
-    document.body.appendChild(container);
-    root = createRoot(container);
-    act(() => {
-      root?.render(
-        createElement(Composer, {
-          agents: [],
-          onSend: (payload) => {
-            sent.push(payload);
-            return Promise.resolve(true);
-          },
-        }),
-      );
-    });
-    typeInto(textarea(), "hello");
-    textarea().setSelectionRange(5, 5);
-    await settle();
-
-    const dictate = container?.querySelector<HTMLButtonElement>('[aria-label="Dictate"]');
-    if (dictate === null || dictate === undefined) {
-      throw new Error("dictate button not found");
-    }
-
-    act(() => {
-      dictate.click();
-    });
-    await settle();
-
-    const rec = recognitions.at(-1);
-    if (rec === undefined) {
-      throw new Error("speech recognition was not constructed");
-    }
-    rec.resultOnStop = [{ isFinal: true, transcript: "late words" }];
-
-    act(() => {
-      sendButton().click();
-    });
-    await settle();
-
-    act(() => {
-      rec.emit([{ isFinal: true, transcript: "late words" }]);
-    });
-    await settle();
-
-    expect(textarea().value).toBe("");
-    expect(sent).toEqual([{ text: "hello", attachments: [] }]);
-  });
-
-  test("Enter while listening does not restore the draft from a late final result", async () => {
-    installSpeechRecognition();
-    const sent: ComposerSendPayload[] = [];
-    container = document.createElement("div");
-    document.body.appendChild(container);
-    root = createRoot(container);
-    act(() => {
-      root?.render(
-        createElement(Composer, {
-          agents: [],
-          onSend: (payload) => {
-            sent.push(payload);
-            return Promise.resolve(true);
-          },
-        }),
-      );
-    });
-    typeInto(textarea(), "hello");
-    textarea().setSelectionRange(5, 5);
-    await settle();
-
-    const dictate = container?.querySelector<HTMLButtonElement>('[aria-label="Dictate"]');
-    if (dictate === null || dictate === undefined) {
-      throw new Error("dictate button not found");
-    }
-
-    act(() => {
-      dictate.click();
-    });
-    await settle();
-
-    const rec = recognitions.at(-1);
-    if (rec === undefined) {
-      throw new Error("speech recognition was not constructed");
-    }
-    rec.resultOnStop = [{ isFinal: true, transcript: "late words" }];
-
-    act(() => {
-      textarea().dispatchEvent(
-        new KeyboardEvent("keydown", {
-          key: "Enter",
-          bubbles: true,
-          cancelable: true,
-        }),
-      );
-    });
-    await settle();
-
-    act(() => {
-      rec.emit([{ isFinal: true, transcript: "late words" }]);
-    });
-    await settle();
-
-    expect(textarea().value).toBe("");
-    expect(sent).toEqual([{ text: "hello", attachments: [] }]);
-  });
-
-  test("stop then send does not restore the draft from a deferred final result", async () => {
-    installSpeechRecognition();
-    const sent: ComposerSendPayload[] = [];
-    container = document.createElement("div");
-    document.body.appendChild(container);
-    root = createRoot(container);
-    act(() => {
-      root?.render(
-        createElement(Composer, {
-          agents: [],
-          onSend: (payload) => {
-            sent.push(payload);
-            return Promise.resolve(true);
-          },
-        }),
-      );
-    });
-    typeInto(textarea(), "hello");
-    textarea().setSelectionRange(5, 5);
-    await settle();
-
-    const dictate = container?.querySelector<HTMLButtonElement>('[aria-label="Dictate"]');
-    if (dictate === null || dictate === undefined) {
-      throw new Error("dictate button not found");
-    }
-
-    act(() => {
-      dictate.click();
-    });
-    await settle();
-
-    const rec = recognitions.at(-1);
-    if (rec === undefined) {
-      throw new Error("speech recognition was not constructed");
-    }
-
-    act(() => {
-      dictate.click();
-    });
-    await settle();
-
-    expect(textarea().value).toBe("hello");
-
-    act(() => {
-      sendButton().click();
-    });
-    await settle();
-
-    act(() => {
-      rec.emit([{ isFinal: true, transcript: "late words" }]);
-    });
-    await settle();
-
-    expect(textarea().value).toBe("");
-    expect(sent).toEqual([{ text: "hello", attachments: [] }]);
-  });
-
-  test("does not report aborted or no-speech recognition errors", async () => {
-    installSpeechRecognition();
-    const report = spyOn(errorSink, "reportError");
-    mount(() => Promise.resolve(true));
-
-    const dictate = container?.querySelector<HTMLButtonElement>('[aria-label="Dictate"]');
-    if (dictate === null || dictate === undefined) {
-      throw new Error("dictate button not found");
-    }
-
-    act(() => {
-      dictate.click();
-    });
-    await settle();
-
-    const rec = recognitions.at(-1);
-    if (rec === undefined) {
-      throw new Error("speech recognition was not constructed");
-    }
-
-    act(() => {
-      rec.onerror?.({ error: "no-speech" });
-      rec.onerror?.({ error: "aborted" });
-    });
-    await settle();
-
-    expect(report).not.toHaveBeenCalled();
-
-    act(() => {
-      rec.onerror?.({ error: "network" });
-    });
-    await settle();
-
-    expect(report).toHaveBeenCalled();
-    report.mockRestore();
-  });
-});
diff --git a/apps/web/src/chat/composer.tsx b/apps/web/src/chat/composer.tsx
deleted file mode 100644
index b71eb1dd5..000000000
--- a/apps/web/src/chat/composer.tsx
+++ /dev/null
@@ -1,901 +0,0 @@
-// The message composer: a plain textarea (Enter sends, Shift+Enter breaks
-// the line), an accessible file picker for attachments, disabled while
-// empty, with an @-mention popover listing the active workbench's agent
-// participants. Kept local and simple rather than adopting the library's
-// `ChatInput` — that component is built around the agent-chat `ChatMessage`
-// model (working/stop) this surface does not use, and its send affordance
-// does not compose with an inline mention popover.
-
-import { Button } from "@corbits/react-ui";
-import { ArrowUp, CircleNotch, Microphone, Paperclip, Stop, X } from "@/lib/icons";
-import { reportError } from "@corbits/error-sink";
-import {
-  forwardRef,
-  useEffect,
-  useImperativeHandle,
-  useLayoutEffect,
-  useRef,
-  useState,
-} from "react";
-import type { ChangeEvent, KeyboardEvent } from "react";
-
-import { CorbitAvatar } from "./avatar";
-import type { Part } from "./api";
-import { activeMentionQuery, filterMentionCandidates, insertMention } from "./mentions";
-import type { MentionCandidate, MentionQuery } from "./mentions";
-import { CHAT_STRINGS } from "./strings";
-
-/** A file the user picked in the composer, already base64-encoded for the wire. */
-export type ComposerAttachment = {
-  readonly id: string;
-  readonly name: string;
-  readonly mediaType: string;
-  readonly data: string;
-};
-
-export type ComposerSendPayload = {
-  readonly text: string;
-  readonly attachments: readonly ComposerAttachment[];
-};
-
-/** Imperative seam a host can grab a ref to, so content from outside the
- * composer's own tree — the profile card's Mention action or
- * hover-edit of a previous prompt — can land in the active draft. */
-export type ComposerHandle = {
-  readonly insertText: (text: string) => void;
-  readonly setText: (text: string) => void;
-};
-
-/** Splice `insertion` in at `caret`, pure and independent of any DOM state
- * so it unit-tests the same way `insertMention` does. */
-export function insertTextAtCaret(
-  value: string,
-  caret: number,
-  insertion: string,
-): { readonly text: string; readonly caret: number } {
-  const before = value.slice(0, caret);
-  const after = value.slice(caret);
-  const text = `${before}${insertion}${after}`;
-  return { text, caret: before.length + insertion.length };
-}
-
-export type SpeechRecognitionAlternativeLike = {
-  readonly transcript: string;
-};
-
-export type SpeechRecognitionResultLike = {
-  readonly isFinal: boolean;
-  readonly length: number;
-  readonly 0: SpeechRecognitionAlternativeLike;
-};
-
-export type SpeechRecognitionEventLike = {
-  readonly results: ArrayLike<SpeechRecognitionResultLike>;
-};
-
-export type SpeechRecognitionLike = {
-  continuous: boolean;
-  interimResults: boolean;
-  onresult: ((event: SpeechRecognitionEventLike) => void) | null;
-  onerror: ((event: unknown) => void) | null;
-  onend: (() => void) | null;
-  start: () => void;
-  stop: () => void;
-  abort: () => void;
-};
-
-type SpeechRecognitionCtor = new () => SpeechRecognitionLike;
-
-function isSpeechRecognitionCtor(value: unknown): value is SpeechRecognitionCtor {
-  return typeof value === "function";
-}
-
-/** Browser `SpeechRecognition` / `webkitSpeechRecognition`, or null. */
-export function speechRecognitionConstructor(
-  global: object = globalThis,
-): SpeechRecognitionCtor | null {
-  if ("SpeechRecognition" in global) {
-    const ctor = Reflect.get(global, "SpeechRecognition");
-    if (isSpeechRecognitionCtor(ctor)) return ctor;
-  }
-  if ("webkitSpeechRecognition" in global) {
-    const ctor = Reflect.get(global, "webkitSpeechRecognition");
-    if (isSpeechRecognitionCtor(ctor)) return ctor;
-  }
-  return null;
-}
-
-function speechRecognitionErrorCode(event: unknown): string | null {
-  if (typeof event !== "object" || event === null) return null;
-  if (!("error" in event)) return null;
-  const { error } = event;
-  if (typeof error !== "string") return null;
-  return error;
-}
-
-function isBenignSpeechRecognitionError(code: string): boolean {
-  return code === "aborted" || code === "no-speech";
-}
-
-function detachDictation(rec: SpeechRecognitionLike) {
-  rec.onresult = null;
-  rec.onerror = null;
-  rec.onend = null;
-}
-
-export function transcriptFromSpeechResults(
-  results: ArrayLike<SpeechRecognitionResultLike>,
-): string {
-  let text = "";
-  for (const result of Array.from(results)) {
-    if (result.length === 0) continue;
-    text += result[0].transcript;
-  }
-  return text;
-}
-
-/**
- * Drop a recognition transcript between `prefix` and `suffix`, inserting a
- * space when the join would otherwise glue two words together.
- */
-export function spliceDictationTranscript(
-  prefix: string,
-  suffix: string,
-  transcript: string,
-): { readonly text: string; readonly caret: number } {
-  const trimmed = transcript.trim();
-  if (trimmed.length === 0) {
-    return { text: `${prefix}${suffix}`, caret: prefix.length };
-  }
-  const head =
-    prefix.length === 0 || /\s$/u.test(prefix) ? `${prefix}${trimmed}` : `${prefix} ${trimmed}`;
-  const text =
-    suffix.length === 0 || /^\s/u.test(suffix) ? `${head}${suffix}` : `${head} ${suffix}`;
-  return { text, caret: head.length };
-}
-
-/**
- * The B2 fix, isolated as a pure rule: a successful send clears the draft;
- * a failed one keeps exactly what the user had typed so nothing is lost.
- */
-export function draftAfterSend(previousValue: string, succeeded: boolean): string {
-  return succeeded ? "" : previousValue;
-}
-
-/**
- * Same rule for selected files: clear the attachment list only after a
- * successful send so a failed post does not force the user to re-pick files.
- */
-export function attachmentsAfterSend(
-  previous: readonly ComposerAttachment[],
-  succeeded: boolean,
-): readonly ComposerAttachment[] {
-  return succeeded ? [] : previous;
-}
-
-/**
- * Build the wire `Part[]` for a composer send. Empty trimmed text is omitted;
- * each attachment becomes a `FilePart` carrying inline base64 `data`.
- */
-export function partsForSend(text: string, attachments: readonly ComposerAttachment[]): Part[] {
-  const parts: Part[] = [];
-  const trimmed = text.trim();
-  if (trimmed.length > 0) {
-    parts.push({ kind: "text", text: trimmed });
-  }
-  for (const file of attachments) {
-    parts.push({
-      kind: "file",
-      name: file.name,
-      mediaType: file.mediaType,
-      data: file.data,
-    });
-  }
-  return parts;
-}
-
-export function canSendComposer(text: string, attachments: readonly ComposerAttachment[]): boolean {
-  return text.trim().length > 0 || attachments.length > 0;
-}
-
-/**
- * Client-side attachment ceilings, kept under the platform's decoded-byte
- * limits (10 MiB per file / 30 MiB total) so a pick fails in the composer
- * rather than after a failed post.
- */
-export const COMPOSER_ATTACHMENT_LIMITS = {
-  maxCount: 5,
-  maxPerFileBytes: 5 * 1024 * 1024,
-  maxTotalBytes: 15 * 1024 * 1024,
-} as const;
-
-export type ComposerAttachmentLimits = {
-  readonly maxCount: number;
-  readonly maxPerFileBytes: number;
-  readonly maxTotalBytes: number;
-};
-
-/** Size metadata available before FileReader runs (File.size). */
-export type AttachmentPickCandidate = {
-  readonly name: string;
-  readonly size: number;
-};
-
-export type AttachmentValidationError =
-  | { readonly kind: "count"; readonly max: number; readonly attempted: number }
-  | {
-      readonly kind: "perFile";
-      readonly name: string;
-      readonly size: number;
-      readonly max: number;
-    }
-  | { readonly kind: "total"; readonly total: number; readonly max: number };
-
-/**
- * Validate a multi-file pick against count, per-file, and total size limits
- * before any FileReader work. Failures are all-or-nothing for the pick.
- */
-export function validateAttachmentPick(
-  existingCount: number,
-  existingTotalBytes: number,
-  candidates: readonly AttachmentPickCandidate[],
-  limits: ComposerAttachmentLimits = COMPOSER_ATTACHMENT_LIMITS,
-): AttachmentValidationError | null {
-  if (candidates.length === 0) return null;
-  const attempted = existingCount + candidates.length;
-  if (attempted > limits.maxCount) {
-    return { kind: "count", max: limits.maxCount, attempted };
-  }
-  let addedBytes = 0;
-  for (const file of candidates) {
-    if (file.size > limits.maxPerFileBytes) {
-      return {
-        kind: "perFile",
-        name: file.name,
-        size: file.size,
-        max: limits.maxPerFileBytes,
-      };
-    }
-    addedBytes += file.size;
-  }
-  const total = existingTotalBytes + addedBytes;
-  if (total > limits.maxTotalBytes) {
-    return { kind: "total", total, max: limits.maxTotalBytes };
-  }
-  return null;
-}
-
-/** Decoded byte length of a standard base64 payload (padding-aware). */
-export function base64DecodedByteLength(data: string): number {
-  if (data.length === 0) return 0;
-  let padding = 0;
-  if (data.endsWith("==")) padding = 2;
-  else if (data.endsWith("=")) padding = 1;
-  return (data.length * 3) / 4 - padding;
-}
-
-export function attachmentBytesOnComposer(attachments: readonly ComposerAttachment[]): number {
-  let total = 0;
-  for (const file of attachments) {
-    total += base64DecodedByteLength(file.data);
-  }
-  return total;
-}
-
-function formatLimitMiB(bytes: number): number {
-  return Math.round(bytes / (1024 * 1024));
-}
-
-export function attachmentValidationMessage(error: AttachmentValidationError): string {
-  switch (error.kind) {
-    case "count":
-      return CHAT_STRINGS.composerAttachmentCountError(error.max);
-    case "perFile":
-      return CHAT_STRINGS.composerAttachmentPerFileError(error.name, formatLimitMiB(error.max));
-    case "total":
-      return CHAT_STRINGS.composerAttachmentTotalError(formatLimitMiB(error.max));
-  }
-}
-
-/** ArrowUp/Enter stay blocked while a send or file read is in flight. */
-export function canSendComposerAction(
-  text: string,
-  attachments: readonly ComposerAttachment[],
-  state: { readonly sending: boolean; readonly preparing: boolean },
-): boolean {
-  if (state.sending || state.preparing) return false;
-  return canSendComposer(text, attachments);
-}
-
-/**
- * Whether the composer offers a Stop affordance — a stand-in
- * for "is there a turn to cancel," reported by the host from its own
- * `isAwaitingReply` signal (the whole in-flight phase, including after
- * tokens have started streaming — not the tokenless `isPendingReply`
- * pulse). Deliberately independent of `sending`/
- * `preparing`: a follow-up message can still be typed and queued while a
- * turn runs (`turn-queue.ts` batches it), so Stop and Send coexist
- * rather than one gating the other.
- */
-export function canStopComposer(state: { readonly running: boolean }): boolean {
-  return state.running;
-}
-
-/** Attach stays blocked while a send or file read is in flight. */
-export function canAttachComposer(state: {
-  readonly sending: boolean;
-  readonly preparing: boolean;
-}): boolean {
-  return !state.sending && !state.preparing;
-}
-
-/**
- * The send button's three visual states: `"empty"` (nothing to send —
- * muted and disabled), `"ready"` (content waiting — primary-orange and
- * enabled), `"sending"` (a send is in flight — primary but disabled, with
- * a spinner in place of the send glyph). Kept as a pure function of the
- * same inputs `canSendComposerAction` already reasons over, so the two
- * never drift on what counts as "there's something to send".
- */
-export type ComposerSendVisualState = "empty" | "ready" | "sending";
-
-export function composerSendVisualState(
-  text: string,
-  attachments: readonly ComposerAttachment[],
-  state: { readonly sending: boolean },
-): ComposerSendVisualState {
-  if (state.sending) return "sending";
-  return canSendComposer(text, attachments) ? "ready" : "empty";
-}
-
-function readFileAsBase64(file: File): Promise<string> {
-  return new Promise((resolve, reject) => {
-    const reader = new FileReader();
-    reader.onload = () => {
-      const result = reader.result;
-      if (typeof result !== "string") {
-        reject(new Error("expected a data URL from FileReader"));
-        return;
-      }
-      const comma = result.indexOf(",");
-      resolve(comma === -1 ? result : result.slice(comma + 1));
-    };
-    reader.onerror = () => reject(reader.error ?? new Error("failed to read attachment"));
-    reader.readAsDataURL(file);
-  });
-}
-
-let attachmentSeq = 0;
-
-function nextAttachmentId(): string {
-  attachmentSeq += 1;
-  return `att_${attachmentSeq}`;
-}
-
-export const Composer = forwardRef<
-  ComposerHandle,
-  {
-    readonly agents: readonly MentionCandidate[];
-    /** Resolves to whether the send succeeded; the composer decides draft/attachment cleanup from that. */
-    readonly onSend: (payload: ComposerSendPayload) => Promise<boolean>;
-    /** Defaults to the generic workbench copy — a chat passes one naming its counterpart. */
-    readonly placeholder?: string;
-    /** Whether a turn is currently running for this workbench —
-     * typically the host's own `isAwaitingReply(streamingReply)`. Absent
-     * or `false` renders no Stop affordance at all. */
-    readonly running?: boolean;
-    /**
-     * Cancels the running turn — `POST .../turns/cancel`. Required
-     * whenever `running` can be `true`; the composer never guesses at
-     * how to stop a turn on its own. May return a promise: a rejection
-     * re-enables the button immediately (the request itself failed —
-     * network, a denied grant — not merely a slow cancel, so there is
-     * no reason to make the person wait for `running` to change before
-     * they can try again).
-     */
-    readonly onStop?: () => void | Promise<unknown>;
-  }
->(function Composer(
-  { agents, onSend, placeholder = CHAT_STRINGS.composerPlaceholder, running = false, onStop },
-  ref,
-) {
-  const [value, setValue] = useState("");
-  const [attachments, setAttachments] = useState<readonly ComposerAttachment[]>([]);
-  const [mention, setMention] = useState<MentionQuery | null>(null);
-  const [highlight, setHighlight] = useState(0);
-  const [sending, setSending] = useState(false);
-  const [preparing, setPreparing] = useState(false);
-  const [errorMessage, setErrorMessage] = useState<string | null>(null);
-  const [focused, setFocused] = useState(false);
-  // Guards Stop against a double-click firing two cancel
-  // requests. A second cancel is harmless server-side (compare-and-set),
-  // but there is no reason to send it. Resets once the host reports the
-  // turn is no longer running -- not on a timer, since a slow cancel
-  // (ceiling) must stay disabled rather than re-arm early.
-  const [stopping, setStopping] = useState(false);
-  const textareaRef = useRef<HTMLTextAreaElement>(null);
-  const fileInputRef = useRef<HTMLInputElement>(null);
-  const attachGenerationRef = useRef(0);
-  // `sending` is React state, set only after `onSend` has already been
-  // awaited into — two calls to `performSend` inside one synchronous tick
-  // (an Enter keydown and a click both firing before a render lands) would
-  // both read `sending === false` and both post. This ref is set the
-  // instant a send starts, synchronously ahead of any render, so a second
-  // call in the same tick is turned away.
-  const sendInFlightRef = useRef(false);
-  const recognitionRef = useRef<SpeechRecognitionLike | null>(null);
-  const dictatePrefixRef = useRef("");
-  const dictateSuffixRef = useRef("");
-  const [listening, setListening] = useState(false);
-  const [dictateAvailable] = useState(() => speechRecognitionConstructor() !== null);
-
-  function stopDictation() {
-    const rec = recognitionRef.current;
-    if (rec === null) return;
-    setListening(false);
-    rec.stop();
-  }
-
-  function abortDictation() {
-    const rec = recognitionRef.current;
-    if (rec === null) return;
-    recognitionRef.current = null;
-    setListening(false);
-    detachDictation(rec);
-    try {
-      rec.abort();
-    } catch {
-      // report-error-ignore: abort() after user Stop is InvalidStateError
-      // once recognition has already ended.
-    }
-  }
-
-  function applyDictationTranscript(transcript: string) {
-    const next = spliceDictationTranscript(
-      dictatePrefixRef.current,
-      dictateSuffixRef.current,
-      transcript,
-    );
-    setValue(next.text);
-    syncComposerSuggestState(next.text, next.caret);
-    requestAnimationFrame(() => {
-      textareaRef.current?.setSelectionRange(next.caret, next.caret);
-    });
-  }
-
-  function startDictation() {
-    abortDictation();
-    const Ctor = speechRecognitionConstructor();
-    if (Ctor === null) return;
-    const textarea = textareaRef.current;
-    const caret = textarea?.selectionStart ?? value.length;
-    dictatePrefixRef.current = value.slice(0, caret);
-    dictateSuffixRef.current = value.slice(caret);
-    const rec = new Ctor();
-    rec.continuous = true;
-    rec.interimResults = true;
-    rec.onresult = (event) => {
-      applyDictationTranscript(transcriptFromSpeechResults(event.results));
-    };
-    rec.onerror = (event) => {
-      const code = speechRecognitionErrorCode(event);
-      if (code === null || !isBenignSpeechRecognitionError(code)) {
-        reportError(event, { operation: "composer.dictate" });
-      }
-      if (recognitionRef.current === rec) {
-        recognitionRef.current = null;
-        setListening(false);
-      }
-    };
-    rec.onend = () => {
-      if (recognitionRef.current !== rec) return;
-      setListening(false);
-    };
-    recognitionRef.current = rec;
-    try {
-      rec.start();
-      setListening(true);
-    } catch (cause) {
-      reportError(cause, { operation: "composer.dictate.start" });
-      recognitionRef.current = null;
-    }
-  }
-
-  function toggleDictation() {
-    if (listening) {
-      stopDictation();
-      return;
-    }
-    startDictation();
-  }
-
-  useEffect(() => {
-    if (!running) setStopping(false);
-  }, [running]);
-
-  useEffect(() => {
-    return () => {
-      const rec = recognitionRef.current;
-      if (rec === null) return;
-      detachDictation(rec);
-      recognitionRef.current = null;
-      rec.abort();
-    };
-  }, []);
-
-  /** Auto-grow: the textarea reports its own content height, so the
-   * measurement resets to the CSS-declared min-height before reading
-   * `scrollHeight` — otherwise a shrinking draft would get stuck at its
-   * tallest-ever height. Growth caps out at the CSS max-height, where
-   * `overflow-y` takes over for scrolling. */
-  useLayoutEffect(() => {
-    const textarea = textareaRef.current;
-    if (textarea === null) return;
-    textarea.style.height = "auto";
-    textarea.style.height = `${textarea.scrollHeight}px`;
-  }, [value]);
-
-  function syncComposerSuggestState(text: string, caret: number) {
-    const openMention = activeMentionQuery(text, caret);
-    setMention(openMention);
-    setHighlight(0);
-  }
-
-  useImperativeHandle(
-    ref,
-    () => ({
-      insertText: (text: string) => {
-        abortDictation();
-        const textarea = textareaRef.current;
-        const caret = textarea?.selectionStart ?? value.length;
-        const result = insertTextAtCaret(value, caret, text);
-        setValue(result.text);
-        requestAnimationFrame(() => {
-          textarea?.focus();
-          textarea?.setSelectionRange(result.caret, result.caret);
-        });
-      },
-      setText: (text: string) => {
-        abortDictation();
-        attachGenerationRef.current += 1;
-        setValue(text);
-        setMention(null);
-        setAttachments([]);
-        setErrorMessage(null);
-        setPreparing(false);
-        requestAnimationFrame(() => {
-          const textarea = textareaRef.current;
-          textarea?.focus();
-          textarea?.setSelectionRange(text.length, text.length);
-        });
-      },
-    }),
-    [value],
-  );
-
-  const mentionOptions: readonly MentionCandidate[] =
-    mention !== null ? filterMentionCandidates(agents, mention.query) : [];
-  const busy = { sending, preparing };
-  const canSend = canSendComposerAction(value, attachments, busy);
-  const canAttach = canAttachComposer(busy);
-  const sendVisualState = composerSendVisualState(value, attachments, {
-    sending,
-  });
-
-  /**
-   * Fires the send and tracks its flight for the button's spinner —
-   * nothing here decides what the timeline shows on success or failure.
-   * The host owns that: it adds an optimistic pending bubble the instant
-   * the payload leaves the composer, then resolves or fails it in place,
-   * so a failed send never comes back here to repopulate the draft —
-   * recovering the text is the pending bubble's own Discard action.
-   */
-  async function performSend(payload: ComposerSendPayload): Promise<void> {
-    if (sendInFlightRef.current) return;
-    sendInFlightRef.current = true;
-    setSending(true);
-    setErrorMessage(null);
-    try {
-      await onSend(payload);
-    } finally {
-      sendInFlightRef.current = false;
-      setSending(false);
-    }
-  }
-
-  /** Splices the picked candidate's handle into the draft. */
-  function pickMention(option: MentionCandidate) {
-    const textarea = textareaRef.current;
-    if (mention === null || textarea === null) return;
-    const caret = textarea.selectionStart;
-    const result = insertMention(value, caret, mention, option.handle);
-    setValue(result.text);
-    setMention(null);
-    requestAnimationFrame(() => {
-      textarea.focus();
-      textarea.setSelectionRange(result.caret, result.caret);
-    });
-  }
-
-  function resetFileInput() {
-    if (fileInputRef.current !== null) {
-      fileInputRef.current.value = "";
-    }
-  }
-
-  async function addFiles(fileList: FileList | null) {
-    if (fileList === null || fileList.length === 0) return;
-    if (!canAttachComposer({ sending, preparing })) return;
-
-    const files = Array.from(fileList);
-    const generation = attachGenerationRef.current;
-    const validation = validateAttachmentPick(
-      attachments.length,
-      attachmentBytesOnComposer(attachments),
-      files.map((file) => ({ name: file.name, size: file.size })),
-    );
-    if (validation !== null) {
-      setErrorMessage(attachmentValidationMessage(validation));
-      resetFileInput();
-      return;
-    }
-
-    setPreparing(true);
-    setErrorMessage(null);
-    try {
-      const next: ComposerAttachment[] = [];
-      for (const file of files) {
-        const data = await readFileAsBase64(file);
-        next.push({
-          id: nextAttachmentId(),
-          name: file.name,
-          mediaType: file.type.length > 0 ? file.type : "application/octet-stream",
-          data,
-        });
-      }
-      // All-or-nothing: only commit once every file in the pick has read.
-      if (attachGenerationRef.current !== generation) return;
-      setAttachments((previous) => [...previous, ...next]);
-    } catch {
-      if (attachGenerationRef.current !== generation) return;
-      setErrorMessage(CHAT_STRINGS.composerAttachmentReadError);
-    } finally {
-      if (attachGenerationRef.current === generation) {
-        setPreparing(false);
-      }
-      resetFileInput();
-    }
-  }
-
-  function removeAttachment(id: string) {
-    setAttachments((previous) => previous.filter((file) => file.id !== id));
-  }
-
-  /**
-   * The draft leaves the box the instant it's handed off, win or lose —
-   * the host's optimistic pending bubble is now the one place that text
-   * lives until the send actually resolves. A failure never repopulates
-   * this box; the bubble's Discard action is the only way text comes
-   * back here (see `ComposerHandle.insertText`, the same seam the
-   * profile card's Mention action uses).
-   */
-  async function send() {
-    if (!canSendComposerAction(value, attachments, { sending, preparing })) {
-      return;
-    }
-    abortDictation();
-    const payload: ComposerSendPayload = { text: value, attachments };
-    setValue("");
-    setAttachments([]);
-    setMention(null);
-    await performSend(payload);
-  }
-
-  function handleKeyDown(event: KeyboardEvent<HTMLTextAreaElement>) {
-    if (mention !== null && mentionOptions.length > 0) {
-      if (event.key === "ArrowDown") {
-        event.preventDefault();
-        setHighlight((index) => (index + 1) % mentionOptions.length);
-        return;
-      }
-      if (event.key === "ArrowUp") {
-        event.preventDefault();
-        setHighlight((index) => (index - 1 + mentionOptions.length) % mentionOptions.length);
-        return;
-      }
-      if (event.key === "Enter" || event.key === "Tab") {
-        event.preventDefault();
-        const chosen = mentionOptions[highlight];
-        if (chosen !== undefined) pickMention(chosen);
-        return;
-      }
-      if (event.key === "Escape") {
-        setMention(null);
-        return;
-      }
-    }
-    if (event.key === "Enter" && !event.shiftKey) {
-      event.preventDefault();
-      void send();
-    }
-  }
-
-  function handleFileChange(event: ChangeEvent<HTMLInputElement>) {
-    void addFiles(event.target.files);
-  }
-
-  function handleStop() {
-    if (stopping || onStop === undefined) return;
-    setStopping(true);
-    // (Critique finding): a rejected stop request is a FAILED
-    // cancel, not a slow one -- the `useEffect` above only re-enables
-    // once the host reports `running` has gone false, which never
-    // happens for a request that never reached the server. Without
-    // this catch the button stayed disabled for the rest of the turn's
-    // life with no way to retry.
-    Promise.resolve(onStop()).catch(() => setStopping(false));
-  }
-
-  return (
-    <div className="chat-composer" data-tour="composer">
-      {mention !== null && (
-        <div className="chat-mention-popover chat-popover-enter" role="listbox">
-          {mentionOptions.length === 0 ? (
-            <div className="chat-mention-empty">{CHAT_STRINGS.mentionEmpty}</div>
-          ) : (
-            <div className="chat-mention-list">
-              {mentionOptions.map((option, index) => (
-                <button
-                  key={option.id}
-                  type="button"
-                  role="option"
-                  aria-selected={index === highlight}
-                  className="chat-mention-option"
-                  data-highlighted={index === highlight}
-                  onMouseDown={(event) => {
-                    event.preventDefault();
-                    pickMention(option);
-                  }}
-                >
-                  <CorbitAvatar ariaLabel={option.label} size="sm" className="mention-avatar" />
-                  <span className="chat-mention-meta">
-                    <span className="chat-mention-name">{option.label}</span>
-                    <span className="chat-mention-handle">@{option.handle}</span>
-                  </span>
-                </button>
-              ))}
-            </div>
-          )}
-        </div>
-      )}
-      <div className="chat-composer-row">
-        <input
-          ref={fileInputRef}
-          type="file"
-          multiple
-          className="chat-composer-file-input"
-          onChange={handleFileChange}
-          tabIndex={-1}
-          aria-hidden="true"
-        />
-        {attachments.length > 0 && (
-          <ul
-            className="chat-composer-attachments"
-            aria-label={CHAT_STRINGS.composerAttachmentsLabel}
-          >
-            {attachments.map((file) => (
-              <li key={file.id} className="chat-composer-attachment">
-                <span className="chat-composer-attachment-name">{file.name}</span>
-                <button
-                  type="button"
-                  className="chat-composer-attachment-remove"
-                  aria-label={CHAT_STRINGS.composerRemoveAttachment(file.name)}
-                  onClick={() => removeAttachment(file.id)}
-                >
-                  <X aria-hidden="true" />
-                </button>
-              </li>
-            ))}
-          </ul>
-        )}
-        <textarea
-          ref={textareaRef}
-          className="chat-composer-input"
-          value={value}
-          placeholder={placeholder}
-          onChange={(event) => {
-            setValue(event.target.value);
-            syncComposerSuggestState(
-              event.target.value,
-              event.target.selectionStart ?? event.target.value.length,
-            );
-          }}
-          onKeyDown={handleKeyDown}
-          onFocus={() => setFocused(true)}
-          onBlur={() => setFocused(false)}
-          readOnly={listening}
-          rows={1}
-        />
-        <div className="chat-composer-actions">
-          <Button
-            type="button"
-            variant="ghost"
-            size="sm"
-            className="chat-composer-icon-button"
-            disabled={!canAttach}
-            onClick={() => fileInputRef.current?.click()}
-            aria-label={CHAT_STRINGS.composerAttach}
-          >
-            <Paperclip />
-          </Button>
-          <span
-            className="chat-composer-keyboard-hint"
-            data-visible={focused && value.trim().length > 0}
-            aria-hidden={!(focused && value.trim().length > 0)}
-          >
-            {CHAT_STRINGS.composerKeyboardHint}
-          </span>
-          <div className="chat-composer-submit-actions">
-            {dictateAvailable ? (
-              <Button
-                type="button"
-                variant="ghost"
-                size="sm"
-                className="chat-composer-icon-button chat-composer-mic"
-                data-listening={listening ? "true" : "false"}
-                aria-pressed={listening}
-                disabled={sending || preparing}
-                onClick={toggleDictation}
-                aria-label={
-                  listening ? CHAT_STRINGS.composerDictateStop : CHAT_STRINGS.composerDictate
-                }
-                title={listening ? CHAT_STRINGS.composerDictateStop : CHAT_STRINGS.composerDictate}
-              >
-                <Microphone aria-hidden="true" />
-              </Button>
-            ) : null}
-            {canStopComposer({ running }) ? (
-              <Button
-                type="button"
-                variant="ghost"
-                size="sm"
-                className="chat-composer-icon-button"
-                disabled={stopping}
-                onClick={handleStop}
-                aria-label={CHAT_STRINGS.composerStop}
-                title={CHAT_STRINGS.composerStop}
-              >
-                <Stop aria-hidden="true" />
-              </Button>
-            ) : null}
-            <Button
-              type="button"
-              variant={sendVisualState === "empty" ? "ghost" : "primary"}
-              size="sm"
-              className="chat-composer-icon-button"
-              disabled={!canSend}
-              data-send-state={sendVisualState}
-              onClick={() => void send()}
-              aria-label={sending ? CHAT_STRINGS.composerSending : CHAT_STRINGS.composerSend}
-              title={sending ? CHAT_STRINGS.composerSending : CHAT_STRINGS.composerSend}
-            >
-              {sendVisualState === "sending" ? (
-                <CircleNotch className="chat-composer-send-spinner" aria-hidden="true" />
-              ) : (
-                <ArrowUp aria-hidden="true" />
-              )}
-            </Button>
-          </div>
-        </div>
-      </div>
-      <div className="chat-composer-status" aria-live="polite" aria-atomic="true">
-        {preparing ? CHAT_STRINGS.composerPreparing : null}
-      </div>
-      {errorMessage !== null && (
-        <div className="chat-composer-error" role="alert">
-          {errorMessage}
-        </div>
-      )}
-    </div>
-  );
-});
diff --git a/apps/web/src/chat/default-agent-workbench.test.ts b/apps/web/src/chat/default-agent-workbench.test.ts
deleted file mode 100644
index 1ba29e9a2..000000000
--- a/apps/web/src/chat/default-agent-workbench.test.ts
+++ /dev/null
@@ -1,126 +0,0 @@
-import { afterEach, describe, expect, test } from "bun:test";
-
-import { createDefaultAgentWorkbench } from "./default-agent-workbench";
-
-type StubDefinition = { readonly id: string; readonly name: string };
-
-function definition(id: string, name: string): StubDefinition {
-  return { id, name };
-}
-
-describe("createDefaultAgentWorkbench", () => {
-  const realFetch = globalThis.fetch;
-
-  afterEach(() => {
-    globalThis.fetch = realFetch;
-  });
-
-  type RecordedCall = { readonly path: string; readonly init?: RequestInit };
-
-  function stubFetch(respond: (path: string) => Response): RecordedCall[] {
-    const calls: RecordedCall[] = [];
-    globalThis.fetch = ((input: RequestInfo | URL, init?: RequestInit) => {
-      const path = typeof input === "string" ? input : new URL(String(input)).pathname;
-      calls.push(init === undefined ? { path } : { path, init });
-      return Promise.resolve(respond(path));
-    }) as typeof fetch;
-    return calls;
-  }
-
-  const json = (body: unknown, status = 200) =>
-    new Response(JSON.stringify(body), {
-      status,
-      headers: { "content-type": "application/json" },
-    });
-
-  test("isCachedWorkbenchId is false until a workbench id is cached", () => {
-    const agent = createDefaultAgentWorkbench({
-      title: "Myra",
-      assetName: "assistant",
-    });
-    expect(agent.isCachedWorkbenchId("chan-1")).toBe(false);
-    expect(agent.isCachedWorkbenchId(null)).toBe(false);
-  });
-
-  test("ensure issues exactly the definition-keyed create, with no list-by-title lookup", async () => {
-    const agent = createDefaultAgentWorkbench({
-      title: "Myra",
-      assetName: "assistant",
-    });
-    const calls = stubFetch((path) => {
-      if (path.endsWith("/chat/workbenches")) {
-        return json({
-          id: "chat-1",
-          title: "Myra",
-          kind: "chat",
-          pinned: false,
-          participants: [],
-        });
-      }
-      throw new Error(`unexpected fetch: ${path}`);
-    });
-
-    const result = await agent.ensure("tnt_1", async () => [
-      definition("def-assistant", "assistant"),
-    ]);
-
-    expect(result).toEqual({ kind: "ready", workbenchId: "chat-1" });
-    expect(calls).toHaveLength(1);
-    const createCall = calls[0];
-    expect(createCall?.path.endsWith("/chat/workbenches")).toBe(true);
-    expect(createCall?.init?.method).toBe("POST");
-    expect(JSON.parse(String(createCall?.init?.body))).toEqual({
-      kind: "chat",
-      definitionId: "def-assistant",
-      name: "Myra",
-      reuseExisting: true,
-    });
-    expect(agent.isCachedWorkbenchId("chat-1")).toBe(true);
-  });
-
-  test("errors when no definition matches the configured asset name", async () => {
-    const agent = createDefaultAgentWorkbench({
-      title: "Myra",
-      assetName: "assistant",
-    });
-
-    const result = await agent.ensure("tnt_1", async () => [definition("def-echo", "echo")]);
-
-    expect(result.kind).toBe("error");
-  });
-
-  test("errors when the configured asset name is undefined", async () => {
-    const agent = createDefaultAgentWorkbench({
-      title: "Myra",
-      assetName: undefined,
-    });
-
-    const result = await agent.ensure("tnt_1", async () => [definition("def-echo", "echo")]);
-
-    expect(result.kind).toBe("error");
-  });
-
-  test("resetCache clears the cached id", async () => {
-    const agent = createDefaultAgentWorkbench({
-      title: "Myra",
-      assetName: "assistant",
-    });
-    stubFetch((path) => {
-      if (path.endsWith("/chat/workbenches")) {
-        return json({
-          id: "chat-1",
-          title: "Myra",
-          kind: "chat",
-          pinned: false,
-          participants: [],
-        });
-      }
-      throw new Error(`unexpected fetch: ${path}`);
-    });
-
-    await agent.ensure("tnt_1", async () => [definition("def-assistant", "assistant")]);
-    expect(agent.isCachedWorkbenchId("chat-1")).toBe(true);
-    agent.resetCache();
-    expect(agent.isCachedWorkbenchId("chat-1")).toBe(false);
-  });
-});
diff --git a/apps/web/src/chat/default-agent-workbench.ts b/apps/web/src/chat/default-agent-workbench.ts
deleted file mode 100644
index de53a2af0..000000000
--- a/apps/web/src/chat/default-agent-workbench.ts
+++ /dev/null
@@ -1,91 +0,0 @@
-// Find-or-create a bench's 1:1 with a given deployed agent, generalizing
-// `apps/web/src/myra-workbench.ts`'s original Myra-specific resolution: this
-// is the one deliberate find-or-create path in the product, the
-// account's home-workbench land-hop (Myra), where landing twice must mean
-// the same conversation, never two. Every other agent-chat creation — "+ New
-// Workbench" picking an agent as a template, a freshly drafted agent's own
-// launch — always mints a new workbench instead.
-//
-// The dedup is entirely the server's: `POST /workbenches` with `kind: "chat"`
-// + `definitionId` find-or-reopens by definition (see
-// `packages/chat/src/routes.ts` `findExistingAgentChat`), so this module
-// issues that create unconditionally and trusts the response rather than
-// pre-checking anything client-side. The agent's title and deployed asset
-// name are config an app supplies — this module carries no product literal
-// of its own.
-
-import { createWorkbench, describeChatError } from "./api";
-
-export type DefaultAgentWorkbenchConfig = {
-  readonly title: string;
-  readonly assetName: string | undefined;
-};
-
-export type EnsureDefaultAgentWorkbenchResult =
-  | { readonly kind: "ready"; readonly workbenchId: string }
-  | { readonly kind: "error"; readonly message: string };
-
-/** An agent definition matched by its deployed asset name — never by
- * display name, which is a UI label, not a wire identifier. */
-export function findDefinitionByAssetName<D extends { readonly name: string }>(
-  definitions: readonly D[],
-  assetName: string | undefined,
-): D | undefined {
-  if (assetName === undefined) return undefined;
-  return definitions.find((definition) => definition.name === assetName);
-}
-
-/**
- * A bound handle over one configured agent: `ensure` resolves or creates
- * its workbench, and the cached id lets a caller answer "is this the
- * default agent's workbench?" synchronously from an id alone, with no
- * workbench-title fetch of its own.
- */
-export function createDefaultAgentWorkbench(config: DefaultAgentWorkbenchConfig) {
-  let cachedWorkbenchId: string | null = null;
-
-  function isCachedWorkbenchId(workbenchId: string | null): boolean {
-    return workbenchId !== null && workbenchId === cachedWorkbenchId;
-  }
-
-  function resetCache(): void {
-    cachedWorkbenchId = null;
-  }
-
-  async function ensure<D extends { readonly id: string; readonly name: string }>(
-    tenantId: string,
-    listDefinitions: (tenantId: string) => Promise<readonly D[]>,
-  ): Promise<EnsureDefaultAgentWorkbenchResult> {
-    try {
-      const definitions = await listDefinitions(tenantId);
-      const definition = findDefinitionByAssetName(definitions, config.assetName);
-      if (definition === undefined) {
-        return {
-          kind: "error",
-          message: `No "${config.title}" agent found for this workbench.`,
-        };
-      }
-      const created = await createWorkbench(tenantId, {
-        kind: "chat",
-        definitionId: definition.id,
-        name: config.title,
-        reuseExisting: true,
-      });
-      cachedWorkbenchId = created.id;
-      return { kind: "ready", workbenchId: created.id };
-    } catch (cause) {
-      return {
-        kind: "error",
-        message: describeChatError(cause, "Couldn't open this workbench."),
-      };
-    }
-  }
-
-  return {
-    ensure,
-    isCachedWorkbenchId,
-    resetCache,
-  };
-}
-
-export type DefaultAgentWorkbench = ReturnType<typeof createDefaultAgentWorkbench>;
diff --git a/apps/web/src/chat/direct-workbench.test.ts b/apps/web/src/chat/direct-workbench.test.ts
deleted file mode 100644
index c0c0356f4..000000000
--- a/apps/web/src/chat/direct-workbench.test.ts
+++ /dev/null
@@ -1,34 +0,0 @@
-import { describe, expect, test } from "bun:test";
-
-import { findDirectWorkbenchWith } from "./direct-workbench";
-import type { Workbench } from "./api";
-
-function workbench(id: string, participantAddresses: readonly string[]): Workbench {
-  return {
-    id,
-    title: id,
-    kind: "chat",
-    pinned: false,
-    participants: participantAddresses.map((address) => ({
-      address,
-      handle: address.split("@")[0] ?? address,
-    })),
-  };
-}
-
-describe("findDirectWorkbenchWith", () => {
-  test("returns the first workbench the subject address participates in", () => {
-    const workbenches = [
-      workbench("c1", ["viewer@x.dev", "someone-else@x.dev"]),
-      workbench("c2", ["viewer@x.dev", "subject@x.dev"]),
-    ];
-
-    expect(findDirectWorkbenchWith(workbenches, "subject@x.dev")?.id).toBe("c2");
-  });
-
-  test("returns undefined when no workbench has that participant", () => {
-    const workbenches = [workbench("c1", ["viewer@x.dev"])];
-
-    expect(findDirectWorkbenchWith(workbenches, "subject@x.dev")).toBeUndefined();
-  });
-});
diff --git a/apps/web/src/chat/direct-workbench.ts b/apps/web/src/chat/direct-workbench.ts
deleted file mode 100644
index 65753da38..000000000
--- a/apps/web/src/chat/direct-workbench.ts
+++ /dev/null
@@ -1,15 +0,0 @@
-// Finding an existing 1:1 by participant address — the read half of the
-// "open-or-create" pattern the profile card's Message action needs
-//, matching by participant address since a profile subject is
-// identified by address, not by a fixed workbench title.
-
-import type { Workbench } from "./api";
-
-export function findDirectWorkbenchWith(
-  workbenches: readonly Workbench[],
-  subjectAddress: string,
-): Workbench | undefined {
-  return workbenches.find((workbench) =>
-    workbench.participants.some((participant) => participant.address === subjectAddress),
-  );
-}
diff --git a/apps/web/src/chat/index.ts b/apps/web/src/chat/index.ts
index 574fb92f7..f1cad3533 100644
--- a/apps/web/src/chat/index.ts
+++ b/apps/web/src/chat/index.ts
@@ -1,21 +1,5 @@
-export { ChatWorkspace } from "./chat-workspace";
-export type {
-  TenantResolution,
-  PresenceMember,
-  ChatHeaderChrome,
-  ChatHeaderCrumb,
-} from "./chat-workspace";
-
-export { WorkbenchTimeline, messageDomId, findRetryText } from "./timeline";
-export { NoUsableModelBanner } from "./no-usable-model-banner";
-export type {
-  CurrentUser,
-  PendingActions,
-  PendingMessageStatus,
-  TimelineMessageItem,
-} from "./timeline";
-
 export { WorkbenchLoadingState } from "./loading-state";
+export { NoUsableModelBanner } from "./no-usable-model-banner";
 
 export {
   CorbitAvatar,
@@ -30,55 +14,10 @@ export {
 } from "./avatar";
 export type { AvatarFill, AvatarColor, CorbitAvatarProps, CorbitAvatarSize } from "./avatar";
 
-export { threadTreeToTimeline } from "./mailbox-timeline";
-export type { TimelineItem } from "./mailbox-timeline";
-
-export {
-  Composer,
-  draftAfterSend,
-  attachmentsAfterSend,
-  partsForSend,
-  canSendComposer,
-  canSendComposerAction,
-  canAttachComposer,
-  COMPOSER_ATTACHMENT_LIMITS,
-  validateAttachmentPick,
-  attachmentValidationMessage,
-  attachmentBytesOnComposer,
-  base64DecodedByteLength,
-  insertTextAtCaret,
-  composerSendVisualState,
-} from "./composer";
-export type {
-  ComposerAttachment,
-  ComposerSendPayload,
-  ComposerAttachmentLimits,
-  AttachmentPickCandidate,
-  AttachmentValidationError,
-  ComposerHandle,
-  ComposerSendVisualState,
-} from "./composer";
-export { renamePayload, rowMenuLabels } from "./sidebar";
-
-export { useWorkbenchStream } from "./use-workbench-stream";
-export type { WorkbenchStreamState } from "./use-workbench-stream";
-
-export {
-  activeMentionQuery,
-  filterMentionCandidates,
-  insertMention,
-  mentionCandidatesFromParticipants,
-} from "./mentions";
-export { agentDisplayNamesFromAgents, displayNameForAddress } from "./agent-display-names";
-export type { AgentDisplayNames } from "./agent-display-names";
-export type { MentionCandidate, MentionQuery } from "./mentions";
-
 export { CHAT_STRINGS } from "./strings";
-export { displayWorkbenchTitle } from "./workbench-display-title";
 
 export { BlockPartView } from "./blocks/registry";
 export { BlockCard } from "./blocks/block-card";
-
 export type {
   ApprovalActions,
   ApprovalLiveStatus,
@@ -93,114 +32,15 @@ export type {
   ConnectAffordance,
 } from "./blocks/connect-service-actions";
 
+export { Markdown } from "./markdown";
+
 export {
-  TextPart,
-  ReasoningPart,
-  ToolTracePart,
-  BlockPart,
-  FilePart,
-  EventPart,
-  Part,
-  WorkbenchKind,
-  isKnownWorkbenchKind,
-  MessageSender,
-  ChatApiError,
-  describeChatError,
+  listWorkbenchTenants,
   listWorkbenches,
-  listAllWorkbenches,
   workbenchesQueryKey,
   workbenchesQueryKeyPrefix,
-  WORKBENCHES_MUTATED_EVENT,
-  WORKBENCHES_MUTATED_STREAM_TYPE,
-  applyStreamWorkbenchesMutated,
-  createWorkbench,
-  listMessages,
-  sendInboxMessage,
-  fetchWorkbenchBlob,
-  listThreads,
-  putReadState,
-  listRuns,
-  listInvitableDefinitions,
-  listTenantInvitableDefinitions,
-  listVisibleAgentDefinitions,
-  openAgentDm,
-  inviteAgent,
-  workbenchStreamUrl,
-  runDisplayName,
-  getWorkbenchSettings,
-  patchWorkbenchSettings,
-  getBenchChatSettings,
-  patchBenchChatSettings,
-  listWorkbenchAgents,
-} from "./api";
-export type {
-  Workbench,
-  CreateWorkbenchInput,
-  ParticipantRecord,
-  MessageItem,
-  MessagesResponse,
-  WorkbenchThread,
-  Run,
-  InvitableDefinition,
-  InvitedAgent,
-  VisibleAgentDefinition,
-  WorkbenchSettings,
-  WorkbenchSettingsPatch,
-  ResolvedContextWindow,
-  BenchChatSettings,
-  BenchChatSettingsPatch,
-  WorkbenchAgent,
-} from "./api";
-export { WorkbenchSettingsSurface } from "./workbench-settings";
-export {
-  workbenchSettingsSections,
-  contextWindowControlState,
-  contextWindowPatchValue,
-  isWorkbenchSettingsSectionId,
-  WORKBENCH_SETTINGS_SECTION_IDS,
-} from "./workbench-settings";
-export type {
-  WorkbenchSettingsSection,
-  WorkbenchSettingsSectionGroup,
-  WorkbenchSettingsSectionId,
-  ContextWindowMode,
-} from "./workbench-settings";
-export { profileSubjectFromParticipant } from "./profile-subject";
-export type { ProfileSubject } from "./profile-subject";
-
-export { sharedWorkbenchesWith } from "./shared-workbenches";
-export type { SharedWorkbenchSummary } from "./shared-workbenches";
-export { findDirectWorkbenchWith } from "./direct-workbench";
+} from "./workbench-tenants";
+export type { Workbench, WorkbenchKind } from "./workbench-tenants";
 
-export { createDefaultAgentWorkbench, findDefinitionByAssetName } from "./default-agent-workbench";
-export type {
-  DefaultAgentWorkbench,
-  DefaultAgentWorkbenchConfig,
-  EnsureDefaultAgentWorkbenchResult,
-} from "./default-agent-workbench";
-
-export { ArtifactChip } from "./artifact-chip";
-
-export { PrThreadView, PrQueuedStrip, PrFailedTurnStrip } from "./pr-thread-view";
-export type {
-  PrThreadRole,
-  PrThreadStatus,
-  PrThreadFixLineKind,
-  PrThreadFixLine,
-  PrThreadSuggestedFix,
-  PrThreadTrace,
-  PrThreadReply,
-  PrThreadFailedTurn,
-  PrThreadNextReviewer,
-  PrThreadFooter,
-  PrThreadViewProps,
-} from "./pr-thread-view";
-
-export {
-  TypingIndicator,
-  parseTypingEvent,
-  nextTypingState,
-  isTypingStateExpired,
-  typingLabel,
-} from "./typing-indicator";
-export type { TypingEvent, TypingState } from "./typing-indicator";
+export { profileSubjectFromParticipant } from "./profile-subject";
+export type { ProfileSubject, ProfileParticipant } from "./profile-subject";
diff --git a/apps/web/src/chat/mailbox-timeline.test.ts b/apps/web/src/chat/mailbox-timeline.test.ts
deleted file mode 100644
index 41e797e20..000000000
--- a/apps/web/src/chat/mailbox-timeline.test.ts
+++ /dev/null
@@ -1,55 +0,0 @@
-import { describe, expect, test } from "bun:test";
-
-import { threadTreeToTimeline } from "./mailbox-timeline";
-
-function envelope(overrides: {
-  messageId: string;
-  from?: string;
-  subject?: string;
-  date?: string;
-}) {
-  return {
-    messageId: overrides.messageId,
-    from: overrides.from ?? "sender@dana.localhost",
-    to: [],
-    subject: overrides.subject ?? "",
-    date: overrides.date ?? "2026-09-17T00:00:00.000Z",
-    references: [],
-  };
-}
-
-describe("threadTreeToTimeline", () => {
-  test("links a reply's threadId to its parent's own uid", () => {
-    const root = {
-      uid: 1,
-      flags: [],
-      envelope: envelope({ messageId: "<msg-1@mail>" }),
-      children: [
-        {
-          uid: 2,
-          flags: [],
-          envelope: envelope({ messageId: "<msg-2@mail>", subject: "reply" }),
-          children: [],
-        },
-      ],
-    };
-
-    const items = threadTreeToTimeline(root);
-
-    expect(items[0]?.threadId).toBeUndefined();
-    expect(items[1]?.threadId).toBe("1");
-  });
-
-  test("a single-node thread has no threadId at all", () => {
-    const root = {
-      uid: 3,
-      flags: [],
-      envelope: envelope({ messageId: "<msg-3@mail>" }),
-      children: [],
-    };
-
-    const [item] = threadTreeToTimeline(root);
-
-    expect(item?.threadId).toBeUndefined();
-  });
-});
diff --git a/apps/web/src/chat/mailbox-timeline.ts b/apps/web/src/chat/mailbox-timeline.ts
deleted file mode 100644
index 6b184f47c..000000000
--- a/apps/web/src/chat/mailbox-timeline.ts
+++ /dev/null
@@ -1,247 +0,0 @@
-// Pure adapter from a mailbox thread read onto the timeline item shape
-// `use-workbench-feed.ts` already produces. No new wire
-// shape: a mail message becomes exactly the `MessageItem` the rest of
-// chat-ui already knows how to render, so the timeline never has to branch
-// on where a message came from.
-//
-// This file makes its own `fetch()` calls against the native
-// `@corbits/mailbox` 1.0 routes (`/me/inbox/threads*`) and validates
-// responses with local arktype schemas rather than a package client,
-// since importing `@corbits/mailbox`'s server-only `migrations.ts` (a
-// `node:crypto` user) at the value level is something a real bundler
-// (Vite/Rollup) walks into even though only types are used, breaking the
-// browser build. Per the owner ruling that `@corbits/mailbox` is a
-// temporary, shrinking surface, every mailbox read in chat-ui goes
-// through this one file, so swapping to Interchange's native mailbox
-// thread shape later is a one-file change.
-//
-// A workbench is a plain Interchange tenant now: there is one
-// chat room per tenant, so the tenant's own `/me/inbox` mailbox already IS
-// that room's mail — there is no per-room `refs` filter to apply any more
-// (the native 1.0 mount dropped `refs` entirely). `roomId` is kept on every
-// function below only so a caller with just a room in hand has a matching
-// call shape; it never narrows which threads come back.
-
-import { type } from "arktype";
-import type { MessageItem, WorkbenchThreadRow } from "./api";
-
-export class MailboxThreadFetchError extends Error {
-  constructor(
-    message: string,
-    readonly status?: number,
-  ) {
-    super(message);
-    this.name = "MailboxThreadFetchError";
-  }
-}
-
-type MailboxThreadNode = {
-  uid: number;
-  flags: string[];
-  envelope: {
-    messageId: string;
-    from: string;
-    to: string[];
-    subject: string;
-    date: string;
-    inReplyTo?: string;
-    references: string[];
-  };
-  children: MailboxThreadNode[];
-};
-
-/** Hand-rolled rather than an arktype schema: the node shape is
- * self-referential (`children: MailboxThreadNode[]`), which arktype only
- * expresses through a named scope — more machinery than a same-shape-at-
- * every-depth check over a server response this file already trusts (the
- * hub's own `mountMailbox`, `enrichThread` in `@corbits/mailbox`'s
- * `mount.ts`) needs. */
-function isMailboxThreadNode(value: unknown): value is MailboxThreadNode {
-  if (typeof value !== "object" || value === null) return false;
-  const node = value as Record<string, unknown>;
-  if (typeof node.uid !== "number") return false;
-  if (!Array.isArray(node.flags) || !node.flags.every((flag) => typeof flag === "string")) {
-    return false;
-  }
-  const envelope = node.envelope as Record<string, unknown> | undefined;
-  if (
-    typeof envelope !== "object" ||
-    envelope === null ||
-    typeof envelope.messageId !== "string" ||
-    typeof envelope.from !== "string" ||
-    !Array.isArray(envelope.to) ||
-    typeof envelope.subject !== "string" ||
-    typeof envelope.date !== "string" ||
-    !Array.isArray(envelope.references)
-  ) {
-    return false;
-  }
-  if (!Array.isArray(node.children) || !node.children.every(isMailboxThreadNode)) {
-    return false;
-  }
-  return true;
-}
-
-const MailboxThreadListResponse = type({
-  threads: "unknown[]",
-});
-
-async function mailboxRequest<T>(
-  path: string,
-  schema: (input: unknown) => T | import("arktype").type.errors,
-): Promise<T> {
-  let response: Response;
-  try {
-    response = await fetch(path);
-  } catch (cause) {
-    throw new MailboxThreadFetchError(cause instanceof Error ? cause.message : String(cause));
-  }
-  if (!response.ok) {
-    throw new MailboxThreadFetchError(
-      `The mailbox answered ${response.status} for ${path}.`,
-      response.status,
-    );
-  }
-  const body: unknown = await response.json().catch(() => undefined);
-  const parsed = schema(body);
-  if (parsed instanceof type.errors) {
-    throw new MailboxThreadFetchError(
-      `Unexpected mailbox response shape from ${path}: ${parsed.summary}`,
-    );
-  }
-  return parsed;
-}
-
-/** The timeline item shape — an alias, not a new type, so a mail-derived
- * row and a chat-native row are interchangeable everywhere the timeline
- * already consumes `MessageItem`. */
-export type TimelineItem = MessageItem;
-
-/** Flattens one thread tree (root plus every descendant) into its member
- * nodes, in the order `enrichThread` builds them (parent, then children). */
-function flattenThread(node: MailboxThreadNode): MailboxThreadNode[] {
-  return [node, ...node.children.flatMap(flattenThread)];
-}
-
-/**
- * Maps one thread tree's nodes onto timeline items.
- *
- * `subject`, when present, prefixes the body as its own line — mail is the
- * only source that carries a subject, so it is folded into the one text
- * part a `MessageItem` has room for rather than inventing a field the rest
- * of chat-ui would have to learn about.
- *
- * `threadId` links a reply to its parent's own `uid` (not its `messageId`,
- * which is the RFC-2822-style id the `inReplyTo`/`references` headers
- * carry) by walking the tree structure the mount already resolved —
- * `executeThread`'s own REFERENCES algorithm, not a second reconstruction
- * from headers here.
- */
-export function threadTreeToTimeline(root: MailboxThreadNode): TimelineItem[] {
-  const items: TimelineItem[] = [];
-  function visit(node: MailboxThreadNode, parentUid: number | undefined) {
-    const { envelope } = node;
-    const text =
-      envelope.subject.length > 0 ? `${envelope.subject}\n${envelope.from}` : envelope.from;
-    items.push({
-      id: String(node.uid),
-      createdAt: envelope.date,
-      parts: [{ kind: "text", text }],
-      sender: { name: null, address: envelope.from },
-      messageId: envelope.messageId,
-      ...(parentUid !== undefined ? { threadId: String(parentUid) } : {}),
-    });
-    for (const child of node.children) visit(child, node.uid);
-  }
-  visit(root, undefined);
-  return items;
-}
-
-function mailboxBasePathFor(tenantId: string): string {
-  return `/api/tenants/${tenantId}/mailbox`;
-}
-
-/** How many of the tenant's most-recently-active mail threads a feed page
- * loads bodies for. More conversations than this simply don't show the
- * older ones yet — there is no "load more" for the root feed today,
- * matching the bound the old `GET /messages` page carried. */
-const ROOM_FEED_THREAD_LIMIT = 50;
-
-/** The `threadId` every root-level message resolves to (via
- * `./thread-feed.ts`'s `threadIdOf`) when it carries none of its own — the
- * same "root feed by default" contract the old `workbench_thread_messages`
- * store stated. A plain, never-a-mailbox-uid sentinel, so it can never
- * collide with a real reply thread's id (a mail message's own uid). */
-export const ROOM_FEED_ROOT_THREAD_ID = "__root__";
-
-async function listThreads(tenantId: string): Promise<MailboxThreadNode[]> {
-  const page = await mailboxRequest(
-    `${mailboxBasePathFor(tenantId)}/me/inbox/threads?folder=INBOX`,
-    MailboxThreadListResponse,
-  );
-  return page.threads.map((raw) => {
-    if (!isMailboxThreadNode(raw)) {
-      throw new MailboxThreadFetchError("Unexpected mailbox thread node shape");
-    }
-    return raw;
-  });
-}
-
-/**
- * Every message across the tenant's mailbox threads, flattened into one
- * timeline — a root message's own `threadId` stays
- * absent (see `threadTreeToTimeline`), so it resolves to
- * `ROOM_FEED_ROOT_THREAD_ID` in `./thread-feed.ts`'s root-feed filter; a
- * reply's `threadId` is its parent's own uid, matching the
- * `WorkbenchThreadRow.id` `loadRoomThreadRows` hands out for the same
- * thread.
- */
-export async function loadRoomMailboxMessages(
-  tenantId: string,
-  _roomId: string,
-): Promise<MessageItem[]> {
-  const threads = (await listThreads(tenantId)).slice(0, ROOM_FEED_THREAD_LIMIT);
-  return threads.flatMap((root) => threadTreeToTimeline(root));
-}
-
-/**
- * The reply-thread affordance rows for the tenant's mailbox threads — only
- * threads with at least one reply get a row, matching the old
- * `GET /threads` contract of listing only real reply activity.
- */
-export async function loadRoomThreadRows(
-  tenantId: string,
-  _roomId: string,
-): Promise<{
-  readonly rootThreadId: string;
-  readonly items: readonly WorkbenchThreadRow[];
-}> {
-  const threads = (await listThreads(tenantId)).slice(0, ROOM_FEED_THREAD_LIMIT);
-  const items: WorkbenchThreadRow[] = threads
-    .map((root) => ({ root, members: flattenThread(root) }))
-    .filter(({ members }) => members.length > 1)
-    .map(({ root, members }) => ({
-      id: String(root.uid),
-      kind: "reply",
-      parentMessageId: String(root.uid),
-      // Every mail thread this feed lists hangs directly off the root
-      // feed — there is no depth-2 mailbox-native sub-thread concept
-      // (see the fork-affordance note in `use-thread-navigation.ts`) —
-      // so `parentThreadId` is always the sentinel root, matching
-      // `useThreadNavigation`'s `depth1Threads` filter
-      // (`thread.parentThreadId === rootThreadId`).
-      parentThreadId: ROOM_FEED_ROOT_THREAD_ID,
-      runRef: null,
-      title: root.envelope.subject.length > 0 ? root.envelope.subject : null,
-      createdAt: members[members.length - 1]?.envelope.date ?? root.envelope.date,
-      replyCount: members.length - 1,
-      lastActivityAt: members[members.length - 1]?.envelope.date ?? root.envelope.date,
-    }));
-  return { rootThreadId: ROOM_FEED_ROOT_THREAD_ID, items };
-}
-
-/** The mailbox SSE endpoint a room's live-update subscription connects
- * to — the same stream `@corbits/mailbox`'s own inbox surface reads. */
-export function roomMailboxEventsUrl(tenantId: string): string {
-  return `${mailboxBasePathFor(tenantId)}/me/inbox/events`;
-}
diff --git a/apps/web/src/chat/mentions.test.ts b/apps/web/src/chat/mentions.test.ts
deleted file mode 100644
index dd89358a0..000000000
--- a/apps/web/src/chat/mentions.test.ts
+++ /dev/null
@@ -1,121 +0,0 @@
-import { describe, expect, test } from "bun:test";
-
-import {
-  activeMentionQuery,
-  filterMentionCandidates,
-  insertMention,
-  mentionCandidatesFromParticipants,
-} from "./mentions";
-
-describe("activeMentionQuery", () => {
-  test("detects an open mention right after the @", () => {
-    expect(activeMentionQuery("hi @re", 6)).toEqual({ start: 3, query: "re" });
-  });
-
-  test("is null with no @ before the caret", () => {
-    expect(activeMentionQuery("hello there", 5)).toBeNull();
-  });
-
-  test("closes once whitespace follows the @", () => {
-    expect(activeMentionQuery("hi @bot now", 11)).toBeNull();
-  });
-
-  test("ignores an email-shaped @ (preceded by a word character)", () => {
-    expect(activeMentionQuery("mail me at a@b", 14)).toBeNull();
-  });
-
-  test("matches a bare @ with an empty query", () => {
-    expect(activeMentionQuery("@", 1)).toEqual({ start: 0, query: "" });
-  });
-});
-
-describe("mentionCandidatesFromParticipants", () => {
-  test("keeps only agent-address participants, keyed by their own handle", () => {
-    expect(
-      mentionCandidatesFromParticipants([
-        { address: "researcher@agents.example", handle: "researcher" },
-        { address: "user_abc123", handle: "user_abc123" },
-        { address: "launch-planner@agents.example", handle: "launch-planner" },
-      ]),
-    ).toEqual([
-      {
-        id: "researcher@agents.example",
-        handle: "researcher",
-        label: "Researcher",
-      },
-      {
-        id: "launch-planner@agents.example",
-        handle: "launch-planner",
-        label: "Launch Planner",
-      },
-    ]);
-  });
-
-  test("a handle friendlier than the local part is used verbatim", () => {
-    expect(
-      mentionCandidatesFromParticipants([
-        { address: "ins_cd03d8e3@agents.example", handle: "echo" },
-      ]),
-    ).toEqual([{ id: "ins_cd03d8e3@agents.example", handle: "echo", label: "Echo" }]);
-  });
-
-  test("returns nothing when no participant is an agent address", () => {
-    expect(
-      mentionCandidatesFromParticipants([{ address: "user_abc123", handle: "user_abc123" }]),
-    ).toEqual([]);
-  });
-
-  test("prefers the resolved display name over the slug-derived label", () => {
-    expect(
-      mentionCandidatesFromParticipants(
-        [
-          { address: "ins_echo@agents.example", handle: "echo" },
-          { address: "ins_review@agents.example", handle: "code-review" },
-        ],
-        new Map([["ins_echo@agents.example", "Myra"]]),
-      ),
-    ).toEqual([
-      { id: "ins_echo@agents.example", handle: "echo", label: "Myra" },
-      {
-        id: "ins_review@agents.example",
-        handle: "code-review",
-        label: "Code Review",
-      },
-    ]);
-  });
-});
-
-describe("filterMentionCandidates", () => {
-  const agents = [
-    { id: "1", handle: "researcher", label: "Researcher" },
-    { id: "2", handle: "reviewer", label: "Reviewer" },
-    { id: "3", handle: "summarizer", label: "Summarizer" },
-  ];
-
-  test("matches by case-insensitive prefix on the handle", () => {
-    expect(filterMentionCandidates(agents, "re")).toEqual(
-      agents.filter((agent) => agent.handle.startsWith("re")),
-    );
-  });
-
-  test("an empty query matches every agent", () => {
-    expect(filterMentionCandidates(agents, "")).toEqual(agents);
-  });
-
-  test("no match returns an empty list", () => {
-    expect(filterMentionCandidates(agents, "zzz")).toEqual([]);
-  });
-});
-
-describe("insertMention", () => {
-  test("splices the mention in with a trailing space and advances the caret", () => {
-    const result = insertMention("hi @re", 6, { start: 3, query: "re" }, "researcher");
-    expect(result.text).toBe("hi @researcher ");
-    expect(result.caret).toBe(result.text.length);
-  });
-
-  test("preserves text after the caret", () => {
-    const result = insertMention("hi @re please", 6, { start: 3, query: "re" }, "researcher");
-    expect(result.text).toBe("hi @researcher  please");
-  });
-});
diff --git a/apps/web/src/chat/mentions.ts b/apps/web/src/chat/mentions.ts
deleted file mode 100644
index 76fcb9115..000000000
--- a/apps/web/src/chat/mentions.ts
+++ /dev/null
@@ -1,125 +0,0 @@
-// Pure @-mention logic for the composer: detecting an in-progress mention at
-// the caret, deriving mentionable candidates from a workbench's participant
-// records, filtering them against the query, and splicing a chosen handle
-// back into the draft. No DOM, no fetch — kept pure so it is unit-testable
-// without mounting anything.
-//
-// A candidate's `handle` comes straight off the participant record the hub
-// returns (`chat/participants`, settings-backed — see
-// `packages/chat/src/participants.ts`), the same friendly, deduplicated
-// mention name `mentionedParticipants` in `packages/chat/src/routes.ts`
-// matches against — never the instance-id local part. Filtering to agent
-// addresses delegates to this package's own `isAgentAddress` (`./wire/mentions`), the same
-// function the server's fan-out uses, so the candidate set is always
-// exactly the set the server will fan a copy to. `label` is a friendlier
-// string shown alongside the handle in the popover only.
-
-import { isAgentAddress } from "./wire/mentions";
-import type { ParticipantRecord } from "./api";
-import { displayNameForAddress, type AgentDisplayNames } from "./agent-display-names";
-
-export type MentionCandidate = {
-  readonly id: string;
-  readonly handle: string;
-  readonly label: string;
-};
-
-/**
- * A softer label for a handle like `launch-planner` or `qa_bot`:
- * word-separators become spaces and each word is capitalized, giving
- * "Launch Planner" — falls back to the raw handle when that would be empty.
- */
-function readableLabel(handle: string): string {
-  const words = handle.split(/[-_]+/).filter((word) => word.length > 0);
-  if (words.length === 0) return handle;
-  return words.map((word) => word.charAt(0).toUpperCase() + word.slice(1)).join(" ");
-}
-
-/**
- * The mentionable agent candidates for a workbench: its agent-address
- * participants (the same set `mentionedParticipants` fans a copy to on the
- * server), each keyed by its own settings-held handle so a picked candidate
- * always inserts text the server will actually match — while the row shows
- * the agent's resolved display name, never the raw slug. Kept
- * agent-only so the composer's `/summarize` path (which needs an agent
- * address) stays honest when it reads from the same helper via the
- * `agents` prop.
- */
-export function mentionCandidatesFromParticipants(
-  participants: readonly ParticipantRecord[],
-  displayNames?: AgentDisplayNames,
-): readonly MentionCandidate[] {
-  return participants
-    .filter((participant) => isAgentAddress(participant.address))
-    .map((participant) => ({
-      id: participant.address,
-      handle: participant.handle,
-      label:
-        displayNameForAddress(participant.address, displayNames) ??
-        readableLabel(participant.handle),
-    }));
-}
-
-export type MentionQuery = {
-  /** Index of the "@" that opened this mention, for splicing the result back in. */
-  readonly start: number;
-  /** Text typed after the "@" so far. */
-  readonly query: string;
-};
-
-/**
- * Looks backward from the caret for an open "@mention": an "@" not
- * preceded by a word character, with no whitespace between it and the
- * caret. Returns `null` when the caret is not inside one — including right
- * after a mention that was closed by a space.
- */
-export function activeMentionQuery(text: string, caret: number): MentionQuery | null {
-  const upToCaret = text.slice(0, caret);
-  const at = upToCaret.lastIndexOf("@");
-  if (at === -1) return null;
-  const before = at === 0 ? "" : upToCaret[at - 1];
-  if (before !== undefined && /\S/.test(before)) return null;
-  const query = upToCaret.slice(at + 1);
-  if (/\s/.test(query)) return null;
-  return { start: at, query };
-}
-
-/**
- * Candidates whose handle or label starts with the query, case-insensitively
- * — matching on the label too so typing a readable prefix still finds the
- * handle it would insert. An empty query matches everyone —
- * the popover opens on a bare "@".
- */
-export function filterMentionCandidates(
-  candidates: readonly MentionCandidate[],
-  query: string,
-): readonly MentionCandidate[] {
-  const needle = query.toLowerCase();
-  return candidates.filter(
-    (candidate) =>
-      candidate.handle.toLowerCase().startsWith(needle) ||
-      candidate.label.toLowerCase().startsWith(needle),
-  );
-}
-
-/**
- * Replaces the open "@query" at `mention.start` with "@handle " (trailing
- * space, so typing continues past the mention rather than into it) and
- * returns the new text plus where the caret lands. `handle` must be the
- * local part of the mentioned participant's address — see the module note
- * above — never a display name.
- */
-export function insertMention(
-  text: string,
-  caret: number,
-  mention: MentionQuery,
-  handle: string,
-): { readonly text: string; readonly caret: number } {
-  const before = text.slice(0, mention.start);
-  const after = text.slice(caret);
-  const inserted = `@${handle} `;
-  return {
-    text: `${before}${inserted}${after}`,
-    caret: before.length + inserted.length,
-  };
-}
diff --git a/apps/web/src/chat/pending-send-lifecycle.test.tsx b/apps/web/src/chat/pending-send-lifecycle.test.tsx
deleted file mode 100644
index 42410b6bd..000000000
--- a/apps/web/src/chat/pending-send-lifecycle.test.tsx
+++ /dev/null
@@ -1,99 +0,0 @@
-// A message the reader just sent must render exactly like a
-// normal message immediately (full opacity, no restyling) with only a
-// small clock glyph while in flight, and never disappear or get replaced
-// once the send fails.
-import { afterEach, describe, expect, test } from "bun:test";
-import { act } from "react";
-import { createRoot } from "react-dom/client";
-import type { Root } from "react-dom/client";
-
-import type { PendingActions, TimelineMessageItem } from "./timeline";
-import { WorkbenchTimeline } from "./timeline";
-
-let container: HTMLDivElement | null = null;
-let root: Root | null = null;
-
-afterEach(() => {
-  if (root !== null) act(() => root?.unmount());
-  container?.remove();
-  container = null;
-  root = null;
-});
-
-async function mount(items: readonly TimelineMessageItem[], pendingActions?: PendingActions) {
-  container = document.createElement("div");
-  document.body.appendChild(container);
-  root = createRoot(container);
-  await act(async () => {
-    root?.render(
-      <WorkbenchTimeline
-        items={items}
-        {...(pendingActions !== undefined ? { pendingActions } : {})}
-      />,
-    );
-  });
-  return container;
-}
-
-describe("pending send lifecycle", () => {
-  test("a sending message renders its bubble with no dimming style and a clock glyph", async () => {
-    const el = await mount([
-      {
-        id: "pending_1",
-        createdAt: "2026-01-01T00:00:00.000Z",
-        parts: [{ kind: "text", text: "hello there" }],
-        sender: { name: null, address: "prn_self1@agents.example" },
-        pendingStatus: "sending",
-        pendingNonce: "nonce_1",
-      },
-    ]);
-
-    const bubble = el.querySelector(".chat-bubble");
-    expect(bubble?.textContent).toContain("hello there");
-    expect(bubble?.getAttribute("style")).toBeNull();
-    expect(el.querySelector(".chat-pending-glyph")).not.toBeNull();
-  });
-
-  // Reopened: a pending send used to render through its own
-  // avatar-less, timestamp-less tier below the real timeline — the exact
-  // mechanism the owner read as "unsent -> sent". It now renders through
-  // the same path (`MessageParts`/`TextBubble`) any confirmed message
-  // does: full avatar, sender name, and local timestamp, with only the
-  // clock glyph as the one "still sending" cue.
-  test("a sending message renders full-fidelity — avatar, sender name, and a real timestamp — not a stripped-down bubble", async () => {
-    const el = await mount([
-      {
-        id: "pending_1",
-        createdAt: "2026-01-01T00:00:00.000Z",
-        parts: [{ kind: "text", text: "hello there" }],
-        sender: { name: null, address: "prn_self1@agents.example" },
-        pendingStatus: "sending",
-        pendingNonce: "nonce_1",
-      },
-    ]);
-
-    expect(el.querySelector(".sender-avatar-button")).not.toBeNull();
-    expect(el.querySelector(".chat-bubble-time")?.textContent).not.toBe("");
-    expect(el.querySelector(".chat-message-actions")).toBeNull();
-  });
-
-  test("a failed send keeps the bubble text visible and adds a retry row, without removing it", async () => {
-    const el = await mount(
-      [
-        {
-          id: "pending_2",
-          createdAt: "2026-01-01T00:00:00.000Z",
-          parts: [{ kind: "text", text: "will retry" }],
-          sender: { name: null, address: "prn_self1@agents.example" },
-          pendingStatus: "failed",
-          pendingNonce: "nonce_2",
-        },
-      ],
-      { onRetry: () => {}, onDiscard: () => {} },
-    );
-
-    expect(el.querySelector(".chat-bubble-text")?.textContent).toBe("will retry");
-    expect(el.querySelector(".chat-pending-failed-label")?.textContent).toBe("Not sent");
-    expect(el.querySelector(".chat-pending-retry")).not.toBeNull();
-  });
-});
diff --git a/apps/web/src/chat/pr-thread-view.tsx b/apps/web/src/chat/pr-thread-view.tsx
deleted file mode 100644
index afcb392ef..000000000
--- a/apps/web/src/chat/pr-thread-view.tsx
+++ /dev/null
@@ -1,352 +0,0 @@
-// The Reviews-room PR thread. Per the mock's own spec note, a thread is a bordered container
-// inside the one timeline -- never a separate page or a master-detail
-// split -- and a reviewer reply uses the same flat avatar-plus-body row as
-// any other message, so a pull-request thread and a plain conversation
-// read as the same medium. This view only renders that container; wiring
-// it into the live timeline against real workbench data is the next slice,
-// so every piece here is pure and props-driven, the same contract
-// `ConnectGithubBlockView` uses.
-//
-// `Avatar` and `Markdown` are the two message-row pieces this file reuses
-// rather than reinventing: `Avatar` is `@corbits/react-ui`'s own initials
-// avatar, and `Markdown` is chat-ui's existing safe-subset renderer, the
-// same one `TextBubble` uses in timeline.tsx. `TextBubble` itself isn't
-// reusable here -- it resolves a reply's identity from `ParticipantRecord`/
-// `CurrentUser` lookups that only exist once a thread is wired to a real
-// workbench, and importing it back out of timeline.tsx would be circular
-// (timeline.tsx already imports the block registry). The role badge
-// ("Host"/"Reviewer") is local for the same reason: it's PR-thread-specific
-// copy, not the generic "Agent" badge `AgentBadge` renders elsewhere.
-// Flagging both `Avatar`+role-badge row and the status chip below as
-// candidates for a shared react-ui primitive once a second surface needs
-// the same shape.
-
-import { Avatar, Badge, Button } from "@corbits/react-ui";
-import type { BadgeTone } from "@corbits/react-ui";
-import { Fragment } from "react";
-
-import { CorbitAvatar, avatarClassForPrincipal } from "./avatar";
-import { Markdown } from "./markdown";
-import { CHAT_STRINGS } from "./strings";
-
-export type PrThreadRole = "host" | "reviewer" | "human";
-
-export type PrThreadStatus =
-  | { readonly kind: "reviewed" }
-  | { readonly kind: "reading" }
-  | { readonly kind: "waiting-on-you" };
-
-export type PrThreadFixLineKind = "context" | "removed" | "added";
-
-export type PrThreadFixLine = {
-  readonly kind: PrThreadFixLineKind;
-  readonly text: string;
-};
-
-export type PrThreadSuggestedFix = {
-  readonly file: string;
-  readonly lines: readonly PrThreadFixLine[];
-  readonly onCopy: () => void;
-  readonly onOpenOnGithub: () => void;
-};
-
-export type PrThreadTrace = {
-  readonly stepCount: number;
-  readonly seconds: number;
-  readonly onViewWork: () => void;
-};
-
-export type PrThreadReply = {
-  readonly id: string;
-  readonly sender: string;
-  readonly role: PrThreadRole;
-  readonly time: string;
-  readonly text: string;
-  readonly trace?: PrThreadTrace;
-  readonly suggestedFix?: PrThreadSuggestedFix;
-};
-
-export type PrThreadFailedTurn = {
-  readonly afterReplyId: string;
-  readonly sender: string;
-  readonly repo: string;
-  readonly onRetry: () => void;
-  readonly onWhatHappened: () => void;
-  /** Overrides the PR-review copy (`prThreadFailedTitle`/`-Sub`, both
-   * scoped to "review"/"repo" language) for a non-PR consumer of this
-   * same strip — the general chat timeline's own failed-turn notice
-   *, which has neither. `repo` stays required so every
-   * existing PR-thread caller is untouched; these two just take
-   * priority over it when present. */
-  readonly titleText?: string;
-  readonly subText?: string;
-};
-
-export type PrThreadNextReviewer = {
-  readonly initials: string;
-  readonly label: string;
-};
-
-export type PrThreadFooter =
-  | {
-      readonly kind: "settled";
-      readonly repo: string;
-      readonly postedAt: string;
-      readonly onViewOnGithub: () => void;
-    }
-  | {
-      readonly kind: "live";
-      readonly nextReviewers: readonly PrThreadNextReviewer[];
-      readonly currentReviewer: string;
-    };
-
-export type PrThreadViewProps = {
-  readonly prNumber: number;
-  readonly title: string;
-  readonly repo: string;
-  readonly author: string;
-  readonly status: PrThreadStatus;
-  readonly replies: readonly PrThreadReply[];
-  readonly failedTurn?: PrThreadFailedTurn;
-  readonly footer: PrThreadFooter;
-};
-
-function initialsFromName(name: string): string {
-  const parts = name.trim().split(/\s+/).filter(Boolean);
-  const first = parts[0]?.[0] ?? "";
-  const second = parts.length > 1 ? (parts[1]?.[0] ?? "") : (parts[0]?.[1] ?? "");
-  return `${first}${second}`.toUpperCase();
-}
-
-function statusChip(status: PrThreadStatus) {
-  const byKind: Record<
-    PrThreadStatus["kind"],
-    { readonly label: string; readonly tone: BadgeTone; readonly live: boolean }
-  > = {
-    reviewed: {
-      label: CHAT_STRINGS.prThreadStatusReviewed,
-      tone: "success",
-      live: false,
-    },
-    reading: {
-      label: CHAT_STRINGS.prThreadStatusReading,
-      tone: "neutral",
-      live: true,
-    },
-    "waiting-on-you": {
-      label: CHAT_STRINGS.prThreadStatusWaitingOnYou,
-      tone: "danger",
-      live: false,
-    },
-  };
-  return byKind[status.kind];
-}
-
-function StatusChip({ status }: { readonly status: PrThreadStatus }) {
-  const { label, tone, live } = statusChip(status);
-  return (
-    <Badge tone={tone} className="chat-pr-status">
-      {live && <span className="chat-pr-status-pulse" aria-hidden="true" />}
-      {label}
-    </Badge>
-  );
-}
-
-function RoleBadge({ role }: { readonly role: PrThreadRole }) {
-  if (role === "human") return null;
-  return (
-    <span className="chat-pr-role-badge" data-role={role}>
-      {role === "host" ? CHAT_STRINGS.prThreadHostBadge : CHAT_STRINGS.prThreadReviewerBadge}
-    </span>
-  );
-}
-
-function TraceButton({ trace }: { readonly trace: PrThreadTrace }) {
-  return (
-    <Button type="button" variant="link" className="chat-pr-trace" onClick={trace.onViewWork}>
-      {CHAT_STRINGS.prThreadViewWork(trace.stepCount, trace.seconds)}
-    </Button>
-  );
-}
-
-function SuggestedFixBlock({ fix }: { readonly fix: PrThreadSuggestedFix }) {
-  return (
-    <div className="chat-pr-fix">
-      <div className="chat-pr-fix-head">
-        <span>{CHAT_STRINGS.prThreadSuggestedFixLabel}</span>
-        <span className="chat-pr-fix-file">{fix.file}</span>
-      </div>
-      <div className="chat-pr-fix-code">
-        <pre>
-          {fix.lines.map((line, index) => (
-            <span key={`${fix.file}-${index}`} className="chat-pr-fix-line" data-kind={line.kind}>
-              {line.text}
-              {"\n"}
-            </span>
-          ))}
-        </pre>
-      </div>
-      <div className="chat-pr-fix-actions">
-        <Button type="button" variant="secondary" size="sm" onClick={fix.onCopy}>
-          {CHAT_STRINGS.prThreadCopyAction}
-        </Button>
-        <Button type="button" variant="secondary" size="sm" onClick={fix.onOpenOnGithub}>
-          {CHAT_STRINGS.prThreadOpenOnGithubAction}
-        </Button>
-      </div>
-    </div>
-  );
-}
-
-function ReplyRow({ reply }: { readonly reply: PrThreadReply }) {
-  const isHuman = reply.role === "human";
-  // No stable reviewer id reaches this pure view (see the file header) —
-  // the reviewer's own display name is already the identity this row
-  // shows, so it doubles as the hash seed for a deterministic per-person
-  // fill (same reviewer, same color, on every reply and every reload).
-  return (
-    <div className="chat-pr-reply">
-      {isHuman ? (
-        <Avatar
-          initials={initialsFromName(reply.sender)}
-          label={reply.sender}
-          tone="neutral"
-          size="lg"
-          className={avatarClassForPrincipal(reply.sender)}
-        />
-      ) : (
-        <CorbitAvatar ariaLabel={reply.sender} size="lg" className="sender-avatar" />
-      )}
-      <div className="chat-pr-reply-body">
-        <div className="chat-pr-reply-head">
-          <span className="chat-pr-reply-sender">{reply.sender}</span>
-          <RoleBadge role={reply.role} />
-          <span className="chat-pr-reply-time">{reply.time}</span>
-        </div>
-        <div className="chat-pr-reply-text">
-          <Markdown text={reply.text} />
-        </div>
-        {reply.suggestedFix !== undefined && <SuggestedFixBlock fix={reply.suggestedFix} />}
-        {reply.trace !== undefined && <TraceButton trace={reply.trace} />}
-      </div>
-    </div>
-  );
-}
-
-export function PrFailedTurnStrip({ failedTurn }: { readonly failedTurn: PrThreadFailedTurn }) {
-  return (
-    <div className="chat-pr-failed" role="status">
-      <span className="chat-pr-failed-text">
-        <strong>
-          {failedTurn.titleText ?? CHAT_STRINGS.prThreadFailedTitle(failedTurn.sender)}
-        </strong>
-        <span className="chat-pr-failed-sub">
-          {failedTurn.subText ?? CHAT_STRINGS.prThreadFailedSub(failedTurn.repo)}
-        </span>
-      </span>
-      <Button type="button" variant="secondary" size="sm" onClick={failedTurn.onRetry}>
-        {CHAT_STRINGS.prThreadRetryAction}
-      </Button>
-      <Button
-        type="button"
-        variant="link"
-        className="chat-pr-failed-what-happened"
-        onClick={failedTurn.onWhatHappened}
-      >
-        {CHAT_STRINGS.prThreadWhatHappenedAction}
-      </Button>
-    </div>
-  );
-}
-
-function ThreadFooter({ footer }: { readonly footer: PrThreadFooter }) {
-  if (footer.kind === "settled") {
-    return (
-      <footer className="chat-pr-foot">
-        <span className="chat-pr-foot-text">
-          {CHAT_STRINGS.prThreadSettledFooter(footer.repo, footer.postedAt)}
-        </span>
-        <Button
-          type="button"
-          variant="link"
-          className="chat-pr-foot-link"
-          onClick={footer.onViewOnGithub}
-        >
-          {CHAT_STRINGS.prThreadViewOnGithub}
-        </Button>
-      </footer>
-    );
-  }
-  return (
-    <footer className="chat-pr-foot">
-      <span className="chat-pr-wait-avatars" aria-hidden="true">
-        {footer.nextReviewers.map((reviewer) => (
-          <CorbitAvatar key={reviewer.label} ariaLabel={reviewer.label} size="sm" />
-        ))}
-      </span>
-      <span className="chat-pr-foot-text">
-        {CHAT_STRINGS.prThreadNextReviewers(
-          footer.nextReviewers.map((reviewer) => reviewer.label),
-          footer.currentReviewer,
-        )}
-      </span>
-    </footer>
-  );
-}
-
-export function PrThreadView({
-  prNumber,
-  title,
-  repo,
-  author,
-  status,
-  replies,
-  failedTurn,
-  footer,
-}: PrThreadViewProps) {
-  return (
-    <article className="chat-pr-thread">
-      <header className="chat-pr-thread-head">
-        <span className="chat-pr-thread-pr">
-          #{prNumber} {title}
-        </span>
-        <span className="chat-pr-thread-repo">
-          {repo} · {author}
-        </span>
-        <span className="chat-pr-thread-status">
-          <StatusChip status={status} />
-        </span>
-      </header>
-      <div className="chat-pr-thread-body">
-        {replies.map((reply) => (
-          <Fragment key={reply.id}>
-            <ReplyRow reply={reply} />
-            {failedTurn !== undefined && failedTurn.afterReplyId === reply.id && (
-              <PrFailedTurnStrip failedTurn={failedTurn} />
-            )}
-          </Fragment>
-        ))}
-      </div>
-      <ThreadFooter footer={footer} />
-    </article>
-  );
-}
-
-export function PrQueuedStrip({
-  prNumber,
-  repo,
-}: {
-  readonly prNumber: number;
-  readonly repo: string;
-}) {
-  return (
-    <div className="chat-pr-queued">
-      <span className="chat-pr-queue-bars" aria-hidden="true">
-        <span />
-        <span />
-        <span />
-      </span>
-      <span>{CHAT_STRINGS.prThreadQueued(prNumber, repo)}</span>
-    </div>
-  );
-}
diff --git a/apps/web/src/chat/profile-subject.ts b/apps/web/src/chat/profile-subject.ts
index f1312f893..1f0a3597a 100644
--- a/apps/web/src/chat/profile-subject.ts
+++ b/apps/web/src/chat/profile-subject.ts
@@ -3,7 +3,12 @@
 
 import { isAgentAddress } from "./wire/mentions";
 
-import type { ParticipantRecord } from "./api";
+/** The identity fields a profile card needs — any participant row with an
+ * address and a handle. */
+export type ProfileParticipant = {
+  readonly address: string;
+  readonly handle: string;
+};
 
 export type ProfileSubject = {
   readonly kind: "agent" | "member";
@@ -25,7 +30,7 @@ function initialsOf(source: string): string {
   return initials.length > 0 ? initials : "?";
 }
 
-export function profileSubjectFromParticipant(participant: ParticipantRecord): ProfileSubject {
+export function profileSubjectFromParticipant(participant: ProfileParticipant): ProfileSubject {
   const isAgent = isAgentAddress(participant.address);
   const displayName = isAgent ? `@${participant.handle}` : participant.handle;
   return {
diff --git a/apps/web/src/chat/refresh-and-send.test.ts b/apps/web/src/chat/refresh-and-send.test.ts
deleted file mode 100644
index 418b923b7..000000000
--- a/apps/web/src/chat/refresh-and-send.test.ts
+++ /dev/null
@@ -1,572 +0,0 @@
-// Pure-logic tests for the reviewed defects fixed on the chat surface. This
-// suite runs in bun's bare test environment (no DOM), so instead of mounting
-// components it exercises the pure rules the fixes turned on: exactly the
-// same rules `chat-workspace.tsx`, `composer.tsx`, and
-// `use-workbench-stream.ts` call from inside their hooks.
-
-import { describe, expect, test } from "bun:test";
-
-import {
-  appendReplyTimedOutNotice,
-  composerPlaceholderFor,
-  mergePendingSends,
-  mergeStreamingReply,
-  withScrollSnapshot,
-} from "./chat-workspace";
-import type { PendingSend } from "./chat-workspace";
-import {
-  attachmentsAfterSend,
-  attachmentBytesOnComposer,
-  attachmentValidationMessage,
-  base64DecodedByteLength,
-  canAttachComposer,
-  canSendComposer,
-  canSendComposerAction,
-  COMPOSER_ATTACHMENT_LIMITS,
-  composerSendVisualState,
-  draftAfterSend,
-  partsForSend,
-  validateAttachmentPick,
-} from "./composer";
-import type { ComposerAttachment } from "./composer";
-import { CHAT_STRINGS } from "./strings";
-import { backoffDelayMs, shouldConnect } from "./use-workbench-stream";
-
-describe("draftAfterSend (B2: a failed send keeps the draft)", () => {
-  test("clears the draft once the send succeeds", () => {
-    expect(draftAfterSend("hello", true)).toBe("");
-  });
-
-  test("keeps exactly what was typed when the send fails", () => {
-    expect(draftAfterSend("hello there", false)).toBe("hello there");
-  });
-});
-
-const sampleAttachment: ComposerAttachment = {
-  id: "att_1",
-  name: "notes.txt",
-  mediaType: "text/plain",
-  data: "aGVsbG8=",
-};
-
-describe("partsForSend (text + file wire shape)", () => {
-  test("emits a text part and a file part with name, mediaType, and data", () => {
-    expect(partsForSend("  hello  ", [sampleAttachment])).toEqual([
-      { kind: "text", text: "hello" },
-      {
-        kind: "file",
-        name: "notes.txt",
-        mediaType: "text/plain",
-        data: "aGVsbG8=",
-      },
-    ]);
-  });
-
-  test("omits empty trimmed text and still sends attachment-only parts", () => {
-    expect(partsForSend("   ", [sampleAttachment])).toEqual([
-      {
-        kind: "file",
-        name: "notes.txt",
-        mediaType: "text/plain",
-        data: "aGVsbG8=",
-      },
-    ]);
-  });
-});
-
-describe("canSendComposer (attachment-only eligibility)", () => {
-  test("allows send with attachments and no text", () => {
-    expect(canSendComposer("", [sampleAttachment])).toBe(true);
-  });
-
-  test("blocks send when both text and attachments are empty", () => {
-    expect(canSendComposer("   ", [])).toBe(false);
-  });
-});
-
-describe("attachmentsAfterSend (clear on success, retain on failure)", () => {
-  test("clears attachments after a successful send", () => {
-    expect(attachmentsAfterSend([sampleAttachment], true)).toEqual([]);
-  });
-
-  test("keeps the same attachments when the send fails", () => {
-    const previous = [sampleAttachment];
-    expect(attachmentsAfterSend(previous, false)).toBe(previous);
-  });
-});
-
-describe("validateAttachmentPick (count / per-file / total limits)", () => {
-  const limits = COMPOSER_ATTACHMENT_LIMITS;
-
-  test("accepts a pick within every limit", () => {
-    expect(
-      validateAttachmentPick(0, 0, [
-        { name: "a.txt", size: 1024 },
-        { name: "b.txt", size: 2048 },
-      ]),
-    ).toBeNull();
-  });
-
-  test("rejects when the pick would exceed max attachment count", () => {
-    const candidates = Array.from({ length: limits.maxCount }, (_, i) => ({
-      name: `f${i}.txt`,
-      size: 1,
-    }));
-    expect(validateAttachmentPick(1, 0, candidates)).toEqual({
-      kind: "count",
-      max: limits.maxCount,
-      attempted: limits.maxCount + 1,
-    });
-  });
-
-  test("rejects a single file over the per-file limit before any read", () => {
-    expect(
-      validateAttachmentPick(0, 0, [{ name: "huge.bin", size: limits.maxPerFileBytes + 1 }]),
-    ).toEqual({
-      kind: "perFile",
-      name: "huge.bin",
-      size: limits.maxPerFileBytes + 1,
-      max: limits.maxPerFileBytes,
-    });
-  });
-
-  test("rejects when existing plus pick total exceeds the message total", () => {
-    // Stay under the per-file ceiling so the total rule is what fires.
-    const chunk = limits.maxPerFileBytes;
-    const existing = limits.maxTotalBytes - chunk + 1;
-    expect(validateAttachmentPick(1, existing, [{ name: "more.bin", size: chunk }])).toEqual({
-      kind: "total",
-      total: existing + chunk,
-      max: limits.maxTotalBytes,
-    });
-  });
-
-  test("is all-or-nothing: one oversize file fails the whole pick", () => {
-    const error = validateAttachmentPick(0, 0, [
-      { name: "ok.txt", size: 10 },
-      { name: "bad.bin", size: limits.maxPerFileBytes + 1 },
-    ]);
-    expect(error?.kind).toBe("perFile");
-  });
-
-  test("maps validation errors to accessible composer copy", () => {
-    expect(
-      attachmentValidationMessage({
-        kind: "count",
-        max: 5,
-        attempted: 6,
-      }),
-    ).toBe(CHAT_STRINGS.composerAttachmentCountError(5));
-    expect(
-      attachmentValidationMessage({
-        kind: "perFile",
-        name: "x.pdf",
-        size: 1,
-        max: 5 * 1024 * 1024,
-      }),
-    ).toBe(CHAT_STRINGS.composerAttachmentPerFileError("x.pdf", 5));
-    expect(
-      attachmentValidationMessage({
-        kind: "total",
-        total: 1,
-        max: 15 * 1024 * 1024,
-      }),
-    ).toBe(CHAT_STRINGS.composerAttachmentTotalError(15));
-  });
-});
-
-describe("base64DecodedByteLength / attachmentBytesOnComposer", () => {
-  test("decodes padding-aware base64 lengths", () => {
-    // "hello" → aGVsbG8=
-    expect(base64DecodedByteLength("aGVsbG8=")).toBe(5);
-    expect(base64DecodedByteLength("")).toBe(0);
-  });
-
-  test("sums attachment payload sizes on the composer", () => {
-    expect(attachmentBytesOnComposer([sampleAttachment])).toBe(5);
-  });
-});
-
-describe("composer busy state rules (preparing blocks send and attach)", () => {
-  test("canSendComposerAction blocks while preparing even with content", () => {
-    expect(
-      canSendComposerAction("", [sampleAttachment], {
-        sending: false,
-        preparing: true,
-      }),
-    ).toBe(false);
-  });
-
-  test("canSendComposerAction blocks while sending", () => {
-    expect(canSendComposerAction("hi", [], { sending: true, preparing: false })).toBe(false);
-  });
-
-  test("canSendComposerAction allows a ready draft", () => {
-    expect(canSendComposerAction("hi", [], { sending: false, preparing: false })).toBe(true);
-  });
-
-  test("canAttachComposer is false while preparing or sending", () => {
-    expect(canAttachComposer({ sending: false, preparing: true })).toBe(false);
-    expect(canAttachComposer({ sending: true, preparing: false })).toBe(false);
-    expect(canAttachComposer({ sending: false, preparing: false })).toBe(true);
-  });
-});
-
-describe("composerPlaceholderFor (names the open recipient)", () => {
-  test("names the counterpart for an agent chat from the workbench title — never a hardcoded agent", () => {
-    expect(composerPlaceholderFor({ kind: "chat", title: "Myra" })).toBe(
-      CHAT_STRINGS.composerPlaceholderChat("Myra"),
-    );
-    expect(composerPlaceholderFor({ kind: "chat", title: "Scout" })).toBe(
-      CHAT_STRINGS.composerPlaceholderChat("Scout"),
-    );
-    expect(composerPlaceholderFor({ kind: "chat", title: "Scout" })).not.toContain("Myra");
-  });
-
-  test("names the counterpart for a person chat too — a chat's title is always its counterpart's name", () => {
-    expect(composerPlaceholderFor({ kind: "chat", title: "Priya" })).toBe(
-      CHAT_STRINGS.composerPlaceholderChat("Priya"),
-    );
-  });
-
-  test("keeps the generic workbench copy for a workbench", () => {
-    expect(composerPlaceholderFor({ kind: "workbench", title: "General" })).toBe(
-      CHAT_STRINGS.composerPlaceholder,
-    );
-  });
-
-  test("keeps the generic copy with no workbench resolved yet", () => {
-    expect(composerPlaceholderFor(undefined)).toBe(CHAT_STRINGS.composerPlaceholder);
-  });
-
-  test("falls back to the unnamed-workbench label for a titleless chat", () => {
-    expect(composerPlaceholderFor({ kind: "chat", title: "" })).toBe(
-      CHAT_STRINGS.composerPlaceholderChat(CHAT_STRINGS.unnamedWorkbench),
-    );
-  });
-});
-
-// This notice used to render as a bare `event`-kind item with no
-// ref id and no Retry — unlike `postUndeliveredNotice`'s server-side
-// backstop for the same class of failure (a turn that ends with no
-// reply). It now carries a `turnFailed` text part instead, so it renders
-// through the same `FailedTurnStrip` treatment: ref id quotable, Retry
-// wired.
-describe("appendReplyTimedOutNotice (same ref+Retry backstop as the server-side notice)", () => {
-  const serverItems = [
-    {
-      id: "m1",
-      createdAt: "2026-01-01T00:00:00.000Z",
-      parts: [{ kind: "text" as const, text: "hello" }],
-      sender: { name: null, address: "prn_alice@acme.example" },
-    },
-  ];
-  const participants = [{ address: "myra@agents.example", handle: "myra" }];
-
-  test("no timeout leaves the timeline untouched", () => {
-    expect(appendReplyTimedOutNotice(serverItems, null, participants)).toBe(serverItems);
-  });
-
-  test("a timed-out turn appends a turnFailed text part carrying the ref id, attributed to the agent", () => {
-    const withNotice = appendReplyTimedOutNotice(serverItems, "mt4ewrje-zvbmti", participants);
-    expect(withNotice).toHaveLength(2);
-    expect(withNotice[1]?.parts).toEqual([
-      {
-        kind: "text",
-        text: "No reply arrived — the agent may be unavailable. (ref mt4ewrje-zvbmti)",
-        turnFailed: true,
-      },
-    ]);
-    expect(withNotice[1]?.sender.address).toBe("myra@agents.example");
-  });
-
-  test("with no agent participant to attribute to, still appends the notice", () => {
-    const withNotice = appendReplyTimedOutNotice(serverItems, "abc-123", []);
-    expect(withNotice).toHaveLength(2);
-    expect(withNotice[1]?.parts[0]).toMatchObject({ turnFailed: true });
-    expect(withNotice[1]?.sender.address).toBe("");
-  });
-});
-
-describe("withScrollSnapshot (settings toggle preserves scroll position)", () => {
-  test("records a new workbench's snapshot without disturbing another workbench's", () => {
-    const withA = withScrollSnapshot(new Map(), "ch_a", {
-      scrollTop: 120,
-      pinned: false,
-    });
-    const withBoth = withScrollSnapshot(withA, "ch_b", {
-      scrollTop: 0,
-      pinned: true,
-    });
-
-    expect(withBoth.get("ch_a")).toEqual({ scrollTop: 120, pinned: false });
-    expect(withBoth.get("ch_b")).toEqual({ scrollTop: 0, pinned: true });
-  });
-
-  test("overwrites a workbench's previous snapshot rather than keeping the stale one", () => {
-    const first = withScrollSnapshot(new Map(), "ch_a", {
-      scrollTop: 50,
-      pinned: false,
-    });
-    const second = withScrollSnapshot(first, "ch_a", {
-      scrollTop: 300,
-      pinned: true,
-    });
-
-    expect(second.get("ch_a")).toEqual({ scrollTop: 300, pinned: true });
-  });
-
-  test("never mutates the map it was given", () => {
-    const original = new Map();
-    withScrollSnapshot(original, "ch_a", { scrollTop: 10, pinned: false });
-    expect(original.size).toBe(0);
-  });
-});
-
-describe("backoffDelayMs (exponential backoff + jitter, capped)", () => {
-  test("the first attempt is the base delay with no jitter", () => {
-    expect(backoffDelayMs(1, () => 0)).toBe(500);
-  });
-
-  test("doubles per attempt", () => {
-    expect(backoffDelayMs(2, () => 0)).toBe(1000);
-    expect(backoffDelayMs(3, () => 0)).toBe(2000);
-    expect(backoffDelayMs(4, () => 0)).toBe(4000);
-  });
-
-  test("caps at the max delay once the exponential curve reaches it, regardless of jitter", () => {
-    expect(backoffDelayMs(5, () => 0)).toBe(8000);
-    expect(backoffDelayMs(20, () => 0)).toBe(8000);
-    expect(backoffDelayMs(20, () => 1)).toBe(8000);
-  });
-
-  test("jitter adds up to 30% on top of the exponential value, never more", () => {
-    expect(backoffDelayMs(1, () => 1)).toBe(650); // 500 + 500*0.3
-    expect(backoffDelayMs(3, () => 1)).toBe(2600); // 2000 + 2000*0.3
-  });
-
-  test("jitter never pushes the delay past the cap", () => {
-    expect(backoffDelayMs(4, () => 1)).toBe(5200); // 4000 + 4000*0.3, under cap
-    expect(backoffDelayMs(5, () => 1)).toBe(8000); // would be 10400 uncapped
-  });
-
-  test("attempt numbers below 1 behave as attempt 1 (no negative exponent)", () => {
-    expect(backoffDelayMs(0, () => 0)).toBe(500);
-    expect(backoffDelayMs(-3, () => 0)).toBe(500);
-  });
-});
-
-describe("shouldConnect (S3: an empty workbench url opens no connection)", () => {
-  test("is false with no active workbench", () => {
-    expect(shouldConnect("")).toBe(false);
-  });
-
-  test("is true once a real stream url is known", () => {
-    expect(shouldConnect("/api/tenants/tnt_1/chat/workbenches/c1/stream")).toBe(true);
-  });
-});
-
-describe("composerSendVisualState (the send button reflects state)", () => {
-  test("empty draft, idle: muted/disabled", () => {
-    expect(composerSendVisualState("", [], { sending: false })).toBe("empty");
-  });
-
-  test("draft present, idle: ready for the primary-orange treatment", () => {
-    expect(composerSendVisualState("hi", [], { sending: false })).toBe("ready");
-  });
-
-  test("a send in flight always wins, even over an emptied draft", () => {
-    expect(composerSendVisualState("", [], { sending: true })).toBe("sending");
-    expect(composerSendVisualState("hi", [], { sending: true })).toBe("sending");
-  });
-
-  test("an attachment with no text still counts as something to send", () => {
-    expect(composerSendVisualState("", [sampleAttachment], { sending: false })).toBe("ready");
-  });
-});
-
-describe("mergePendingSends (optimistic sends fold into the timeline)", () => {
-  const serverItems = [
-    {
-      id: "m1",
-      createdAt: "2026-01-01T00:00:00.000Z",
-      parts: [{ kind: "text" as const, text: "hello" }],
-      sender: { name: null, address: "prn_alice@acme.example" },
-    },
-  ];
-
-  test("no pending sends leaves the server list untouched", () => {
-    expect(mergePendingSends(serverItems, [], "prn_alice")).toBe(serverItems);
-  });
-
-  test("a pending send appends after the server's own messages, marked sending", () => {
-    const pending: PendingSend[] = [
-      {
-        nonce: "pending_1",
-        text: "hi",
-        attachments: [],
-        createdAt: "2026-01-01T00:01:00.000Z",
-        status: "sending",
-      },
-    ];
-    const merged = mergePendingSends(serverItems, pending, "prn_alice");
-    expect(merged).toHaveLength(2);
-    expect(merged[1]).toMatchObject({
-      pendingStatus: "sending",
-      pendingNonce: "pending_1",
-    });
-    expect(merged[1]?.parts).toEqual([{ kind: "text", text: "hi" }]);
-  });
-
-  test("a pending item's own clientId matches its nonce, so it keys identically to whichever confirmed message later reconciles it", () => {
-    const pending: PendingSend[] = [
-      {
-        nonce: "pending_1",
-        text: "hi",
-        attachments: [],
-        createdAt: "2026-01-01T00:01:00.000Z",
-        status: "sending",
-      },
-    ];
-    const merged = mergePendingSends(serverItems, pending, "prn_alice");
-    // The timeline keys every item by `clientId ?? id` (see
-    // `WorkbenchTimeline`'s render loop) so a pending bubble and its later
-    // confirmed copy — same `clientId` — update one DOM node in place
-    // rather than unmount/remount as two unrelated items.
-    expect(merged[1]?.clientId).toBe("pending_1");
-  });
-
-  test('a pending send\'s sender local part matches the signed-in principal, so it renders as "You"', () => {
-    const pending: PendingSend[] = [
-      {
-        nonce: "pending_1",
-        text: "hi",
-        attachments: [],
-        createdAt: "2026-01-01T00:01:00.000Z",
-        status: "failed",
-      },
-    ];
-    const merged = mergePendingSends([], pending, "prn_alice");
-    expect(merged[0]?.sender.address.split("@")[0]).toBe("prn_alice");
-    expect(merged[0]?.pendingStatus).toBe("failed");
-  });
-});
-
-describe("mergePendingSends (clientId reconciliation never double-renders a send)", () => {
-  const serverItems = [
-    {
-      id: "m1",
-      createdAt: "2026-01-01T00:00:00.000Z",
-      parts: [{ kind: "text" as const, text: "hello" }],
-      sender: { name: null, address: "prn_alice@acme.example" },
-    },
-  ];
-  const pending: PendingSend[] = [
-    {
-      nonce: "pending_1",
-      text: "hi",
-      attachments: [],
-      createdAt: "2026-01-01T00:01:00.000Z",
-      status: "sending",
-    },
-  ];
-
-  test("stream-first: a confirmed item carrying this send's clientId lands before the POST resolves — no duplicate", () => {
-    const itemsWithConfirmedCopy = [
-      ...serverItems,
-      {
-        id: "m2",
-        createdAt: "2026-01-01T00:01:05.000Z",
-        parts: [{ kind: "text" as const, text: "hi" }],
-        sender: { name: null, address: "prn_alice@acme.example" },
-        clientId: "pending_1",
-      },
-    ];
-    const merged = mergePendingSends(itemsWithConfirmedCopy, pending, "prn_alice");
-    expect(merged).toHaveLength(2);
-    expect(merged.filter((item) => item.pendingStatus !== undefined)).toHaveLength(0);
-  });
-
-  test("POST-first: the pending entry is still present when the confirmed item hasn't loaded yet — renders once, as pending", () => {
-    const merged = mergePendingSends(serverItems, pending, "prn_alice");
-    expect(merged).toHaveLength(2);
-    expect(merged[1]?.pendingStatus).toBe("sending");
-  });
-
-  test("a confirmed item with a different clientId (another send, or none at all) never suppresses this pending entry", () => {
-    const itemsWithUnrelatedClientId = [
-      {
-        id: "m2",
-        createdAt: "2026-01-01T00:01:05.000Z",
-        parts: [{ kind: "text" as const, text: "unrelated" }],
-        sender: { name: null, address: "prn_alice@acme.example" },
-        clientId: "pending_other",
-      },
-    ];
-    const merged = mergePendingSends(itemsWithUnrelatedClientId, pending, "prn_alice");
-    expect(merged).toHaveLength(2);
-    expect(merged[1]?.pendingStatus).toBe("sending");
-  });
-
-  test("a failed send's single bubble stays exactly one bubble even once its clientId is confirmed (e.g. a stale retry landed)", () => {
-    const failedPending: PendingSend[] = [
-      {
-        nonce: "pending_1",
-        text: "hi",
-        attachments: [],
-        createdAt: "2026-01-01T00:01:00.000Z",
-        status: "failed",
-      },
-    ];
-    const itemsWithConfirmedCopy = [
-      {
-        id: "m2",
-        createdAt: "2026-01-01T00:01:05.000Z",
-        parts: [{ kind: "text" as const, text: "hi" }],
-        sender: { name: null, address: "prn_alice@acme.example" },
-        clientId: "pending_1",
-      },
-    ];
-    const merged = mergePendingSends(itemsWithConfirmedCopy, failedPending, "prn_alice");
-    expect(merged).toHaveLength(1);
-    expect(merged[0]?.pendingStatus).toBeUndefined();
-  });
-});
-
-describe("mergeStreamingReply (the in-progress agent reply folds into the timeline)", () => {
-  const agent = { address: "myra@ins_abc123", handle: "myra" };
-  const serverItems = [
-    {
-      id: "m1",
-      createdAt: "2026-01-01T00:00:00.000Z",
-      parts: [{ kind: "text" as const, text: "hello" }],
-      sender: { name: null, address: "prn_alice@acme.example" },
-    },
-  ];
-
-  test("no in-progress reply leaves the timeline untouched", () => {
-    expect(mergeStreamingReply(serverItems, null, [agent])).toBe(serverItems);
-  });
-
-  test("a growing reply appends a streaming item attributed to the workbench's agent", () => {
-    const merged = mergeStreamingReply(serverItems, { phase: "awaiting", text: "Working on it" }, [
-      agent,
-    ]);
-    expect(merged).toHaveLength(2);
-    expect(merged[1]).toMatchObject({
-      streaming: true,
-      sender: { address: "myra@ins_abc123" },
-    });
-    expect(merged[1]?.parts).toEqual([{ kind: "text", text: "Working on it" }]);
-  });
-
-  test("no agent participant to attribute the reply to means no synthetic item", () => {
-    const merged = mergeStreamingReply(serverItems, { phase: "awaiting", text: "hi" }, []);
-    expect(merged).toBe(serverItems);
-  });
-
-  test("a pending reply with no tokens yet renders no ghost bubble — the typing line owns that phase", () => {
-    const merged = mergeStreamingReply(serverItems, { phase: "awaiting", text: "" }, [agent]);
-    expect(merged).toBe(serverItems);
-  });
-});
diff --git a/apps/web/src/chat/shared-workbenches.test.ts b/apps/web/src/chat/shared-workbenches.test.ts
deleted file mode 100644
index db890d537..000000000
--- a/apps/web/src/chat/shared-workbenches.test.ts
+++ /dev/null
@@ -1,66 +0,0 @@
-import { describe, expect, test } from "bun:test";
-
-import { sharedWorkbenchesWith } from "./shared-workbenches";
-import type { Workbench } from "./api";
-
-function workbench(id: string, title: string, participantAddresses: readonly string[]): Workbench {
-  return {
-    id,
-    title,
-    kind: "workbench",
-    pinned: false,
-    participants: participantAddresses.map((address) => ({
-      address,
-      handle: address.split("@")[0] ?? address,
-    })),
-  };
-}
-
-describe("sharedWorkbenchesWith", () => {
-  test("keeps only workbenches both the viewer and the subject participate in", () => {
-    const workbenches = [
-      workbench("c1", "General", ["viewer@x.dev", "subject@x.dev"]),
-      workbench("c2", "Viewer only", ["viewer@x.dev", "someone-else@x.dev"]),
-      workbench("c3", "Subject only", ["subject@x.dev", "someone-else@x.dev"]),
-    ];
-
-    const result = sharedWorkbenchesWith(workbenches, "viewer", "subject@x.dev");
-
-    expect(result.map((c) => c.id)).toEqual(["c1"]);
-  });
-
-  test("matches the viewer by principal id against the participant address's local part", () => {
-    const workbenches = [workbench("c1", "DM", ["ins_abc@x.dev", "viewer@x.dev"])];
-
-    const result = sharedWorkbenchesWith(workbenches, "viewer", "ins_abc@x.dev");
-
-    expect(result).toHaveLength(1);
-  });
-
-  test("caps the result at the given limit, mock parity default of 4", () => {
-    const workbenches = Array.from({ length: 6 }, (_, i) =>
-      workbench(`c${i}`, `Workbench ${i}`, ["viewer@x.dev", "subject@x.dev"]),
-    );
-
-    expect(sharedWorkbenchesWith(workbenches, "viewer", "subject@x.dev")).toHaveLength(4);
-    expect(sharedWorkbenchesWith(workbenches, "viewer", "subject@x.dev", 2)).toHaveLength(2);
-  });
-
-  test("reports each shared workbench's title and member count", () => {
-    const workbenches = [
-      workbench("c1", "Launch planning", ["viewer@x.dev", "subject@x.dev", "third@x.dev"]),
-    ];
-
-    const result = sharedWorkbenchesWith(workbenches, "viewer", "subject@x.dev");
-
-    expect(result).toEqual([{ id: "c1", title: "Launch planning", memberCount: 3 }]);
-  });
-
-  test("falls back to a placeholder title for an untitled workbench", () => {
-    const workbenches = [workbench("c1", "", ["viewer@x.dev", "subject@x.dev"])];
-
-    const result = sharedWorkbenchesWith(workbenches, "viewer", "subject@x.dev");
-
-    expect(result[0]?.title).toBe("Untitled conversation");
-  });
-});
diff --git a/apps/web/src/chat/shared-workbenches.ts b/apps/web/src/chat/shared-workbenches.ts
deleted file mode 100644
index 04c6358cd..000000000
--- a/apps/web/src/chat/shared-workbenches.ts
+++ /dev/null
@@ -1,48 +0,0 @@
-// Which workbenches a profile's shared-workbenches list shows: every
-// workbench where both the signed-in viewer and the profile's subject are
-// participants. Mirrors the mock's `openProfile` filter
-// (`workbenchOrder.filter(members.some(subject))`, capped at 4) over the real
-// `Workbench.participants` feed instead of the mock's in-memory fixture.
-
-import { localPartOf } from "./wire/agent-address";
-
-import type { Workbench } from "./api";
-
-const DEFAULT_LIMIT = 4;
-
-export type SharedWorkbenchSummary = {
-  readonly id: string;
-  readonly title: string;
-  readonly memberCount: number;
-};
-
-/**
- * `viewerPrincipalId` matches a participant by address local part — a
- * sender/participant address's local part IS the owning principal's id (see
- * `packages/chat-ui/src/timeline.tsx`'s `CurrentUser` doc comment) — while
- * `subjectAddress` matches by exact address, since a `ProfileSubject` always
- * carries the full address it was opened from.
- */
-export function sharedWorkbenchesWith(
-  workbenches: readonly Workbench[],
-  viewerPrincipalId: string,
-  subjectAddress: string,
-  limit: number = DEFAULT_LIMIT,
-): readonly SharedWorkbenchSummary[] {
-  return workbenches
-    .filter((workbench) => {
-      const hasViewer = workbench.participants.some(
-        (participant) => localPartOf(participant.address) === viewerPrincipalId,
-      );
-      const hasSubject = workbench.participants.some(
-        (participant) => participant.address === subjectAddress,
-      );
-      return hasViewer && hasSubject;
-    })
-    .slice(0, limit)
-    .map((workbench) => ({
-      id: workbench.id,
-      title: workbench.title.trim().length > 0 ? workbench.title : "Untitled conversation",
-      memberCount: workbench.participants.length,
-    }));
-}
diff --git a/apps/web/src/chat/sidebar.tsx b/apps/web/src/chat/sidebar.tsx
deleted file mode 100644
index 79646a94f..000000000
--- a/apps/web/src/chat/sidebar.tsx
+++ /dev/null
@@ -1,32 +0,0 @@
-// Pure helpers for workbench-row menus. The page-local ChatSidebar surface is
-// gone — the app shell's panel contributions own the workbench list.
-
-import type { Workbench } from "./api";
-import { CHAT_STRINGS } from "./strings";
-
-/**
- * The row menu's item labels for a given workbench, pure so its pinned-state
- * wording ("Pin" vs "Unpin") is testable without opening the (portaled,
- * Radix-controlled) menu itself.
- */
-export function rowMenuLabels(
-  workbench: Pick<Workbench, "pinned">,
-): readonly [rename: string, pin: string, settings: string] {
-  return [
-    CHAT_STRINGS.rowMenuRename,
-    workbench.pinned ? CHAT_STRINGS.rowMenuUnpin : CHAT_STRINGS.rowMenuPin,
-    CHAT_STRINGS.rowMenuSettings,
-  ];
-}
-
-/**
- * What a rename submission should send: `undefined` for input that resolves
- * to nothing worth saving (blank, or unchanged from the workbench's current
- * title) — the caller's cue to treat the rename as a no-op cancel rather
- * than an empty-name PATCH.
- */
-export function renamePayload(input: string, currentTitle: string): string | undefined {
-  const trimmed = input.trim();
-  if (trimmed.length === 0 || trimmed === currentTitle) return undefined;
-  return trimmed;
-}
diff --git a/apps/web/src/chat/single-message-list-reconciliation.test.tsx b/apps/web/src/chat/single-message-list-reconciliation.test.tsx
deleted file mode 100644
index 23550b408..000000000
--- a/apps/web/src/chat/single-message-list-reconciliation.test.tsx
+++ /dev/null
@@ -1,113 +0,0 @@
-// Reopened: dedup by clientId alone still let a sent message read
-// as "unsent -> sent" because the pending bubble and its confirmed copy
-// were two structurally different renders (a stripped-down pending tier
-// swapping for a full bubble under a brand-new React key). This suite
-// covers the fix directly: one message list, keyed by clientId, so a
-// pending entry and its later confirmed copy share a DOM identity and
-// every interleaving between POST and background refresh renders exactly
-// one bubble.
-import { afterEach, describe, expect, test } from "bun:test";
-import { act } from "react";
-import { createRoot } from "react-dom/client";
-import type { Root } from "react-dom/client";
-
-import type { MessageItem } from "./api";
-import type { TimelineMessageItem } from "./timeline";
-import { WorkbenchTimeline } from "./timeline";
-
-let container: HTMLDivElement | null = null;
-let root: Root | null = null;
-
-afterEach(() => {
-  if (root !== null) act(() => root?.unmount());
-  container?.remove();
-  container = null;
-  root = null;
-});
-
-async function render(items: readonly TimelineMessageItem[]) {
-  if (container === null) {
-    container = document.createElement("div");
-    document.body.appendChild(container);
-    root = createRoot(container);
-  }
-  await act(async () => {
-    root?.render(
-      <WorkbenchTimeline
-        items={items}
-        currentUser={{ principalId: "prn_alice" }}
-        pendingActions={{ onRetry: () => {}, onDiscard: () => {} }}
-      />,
-    );
-  });
-  return container;
-}
-
-const pendingItem: TimelineMessageItem = {
-  id: "pending_1",
-  createdAt: "2026-01-01T00:00:00.000Z",
-  parts: [{ kind: "text", text: "hi" }],
-  sender: { name: null, address: "prn_alice@pending.local" },
-  clientId: "pending_1",
-  pendingStatus: "sending",
-  pendingNonce: "pending_1",
-};
-
-const confirmedItem: MessageItem = {
-  id: "m1",
-  createdAt: "2026-01-01T00:00:00.500Z",
-  parts: [{ kind: "text", text: "hi" }],
-  sender: { name: "Alice", address: "prn_alice@acme.example" },
-  clientId: "pending_1",
-};
-
-describe("one message list: a pending send reconciles in place under a stable key", () => {
-  test("POST-first: sending, then the same key's props update to confirmed — one group throughout, same DOM node", async () => {
-    const el = await render([pendingItem]);
-    const avatarBefore = el.querySelector(".sender-avatar-button");
-    expect(el.querySelectorAll(".chat-message-group")).toHaveLength(1);
-    expect(el.querySelector(".chat-pending-glyph")).not.toBeNull();
-
-    await render([confirmedItem]);
-
-    expect(el.querySelectorAll(".chat-message-group")).toHaveLength(1);
-    expect(el.querySelector(".chat-pending-glyph")).toBeNull();
-    const avatarAfter = el.querySelector(".sender-avatar-button");
-    // Same `clientId` key means React updates the existing node's props
-    // rather than unmounting and mounting a new one.
-    expect(avatarAfter).not.toBeNull();
-    expect(avatarAfter?.isSameNode(avatarBefore)).toBe(true);
-  });
-
-  test("refresh-first: a background refresh lands the confirmed copy while the send is still marked pending — renders once, never both", async () => {
-    // mergePendingSends already drops a pending entry once a confirmed
-    // item with a matching clientId shows up; this is what the host
-    // hands WorkbenchTimeline once that dedup has run.
-    const el = await render([confirmedItem]);
-    expect(el.querySelectorAll(".chat-message-group")).toHaveLength(1);
-    expect(el.querySelector(".chat-pending-glyph")).toBeNull();
-  });
-
-  test("refresh-without-the-message-yet, then POST resolves: the pending bubble stays the one and only render, no gap", async () => {
-    const el = await render([pendingItem]);
-    // A background refresh that doesn't yet carry this send changes
-    // nothing about the pending entry — still exactly one group, still
-    // marked sending.
-    await render([pendingItem]);
-    expect(el.querySelectorAll(".chat-message-group")).toHaveLength(1);
-    expect(el.querySelector(".chat-pending-glyph")).not.toBeNull();
-
-    await render([confirmedItem]);
-    expect(el.querySelectorAll(".chat-message-group")).toHaveLength(1);
-    expect(el.querySelector(".chat-pending-glyph")).toBeNull();
-  });
-
-  test("failure: the same bubble flips to the failed affordance in place, never a second bubble", async () => {
-    const el = await render([pendingItem]);
-    await render([{ ...pendingItem, pendingStatus: "failed" }]);
-
-    expect(el.querySelectorAll(".chat-message-group")).toHaveLength(1);
-    expect(el.querySelector(".chat-pending-glyph")).toBeNull();
-    expect(el.querySelector(".chat-pending-failed-label")).not.toBeNull();
-  });
-});
diff --git a/apps/web/src/chat/stream-apply.test.ts b/apps/web/src/chat/stream-apply.test.ts
deleted file mode 100644
index 9bf1391a6..000000000
--- a/apps/web/src/chat/stream-apply.test.ts
+++ /dev/null
@@ -1,62 +0,0 @@
-// `ensureReplyThreadRow` is the pure fold `use-optimistic-sends.ts`
-// calls to seed (or bump) a reply-thread row in the threads cache before
-// navigation opens it.
-
-import { describe, expect, test } from "bun:test";
-
-import { ensureReplyThreadRow } from "./use-workbench-feed";
-import type { WorkbenchThreadRow } from "./api";
-
-describe("ensureReplyThreadRow", () => {
-  const empty: {
-    readonly rootThreadId: string;
-    readonly items: readonly WorkbenchThreadRow[];
-  } = { rootThreadId: "root", items: [] };
-
-  test("seeds a missing reply-thread row with parentMessageId and replyCount 1", () => {
-    const next = ensureReplyThreadRow(empty, {
-      threadId: "thr_new",
-      createdAt: "2026-01-01T00:01:00.000Z",
-      parentMessageId: "m_parent",
-    });
-    expect(next.items).toEqual([
-      {
-        id: "thr_new",
-        kind: "reply",
-        parentMessageId: "m_parent",
-        parentThreadId: "root",
-        runRef: null,
-        title: null,
-        createdAt: "2026-01-01T00:01:00.000Z",
-        replyCount: 1,
-        lastActivityAt: "2026-01-01T00:01:00.000Z",
-      },
-    ]);
-  });
-
-  test("fills a null parentMessageId on an existing stub without overwriting a real parent", () => {
-    const withStub = ensureReplyThreadRow(empty, {
-      threadId: "thr_new",
-      createdAt: "2026-01-01T00:01:00.000Z",
-      bumpReplyCount: false,
-    });
-    expect(withStub.items[0]?.parentMessageId).toBeNull();
-    expect(withStub.items[0]?.replyCount).toBe(0);
-
-    const filled = ensureReplyThreadRow(withStub, {
-      threadId: "thr_new",
-      createdAt: "2026-01-01T00:02:00.000Z",
-      parentMessageId: "m_parent",
-      bumpReplyCount: false,
-    });
-    expect(filled.items[0]?.parentMessageId).toBe("m_parent");
-
-    const kept = ensureReplyThreadRow(filled, {
-      threadId: "thr_new",
-      createdAt: "2026-01-01T00:03:00.000Z",
-      parentMessageId: "m_other",
-      bumpReplyCount: false,
-    });
-    expect(kept.items[0]?.parentMessageId).toBe("m_parent");
-  });
-});
diff --git a/apps/web/src/chat/streaming-reply.test.ts b/apps/web/src/chat/streaming-reply.test.ts
deleted file mode 100644
index 467cc8dbd..000000000
--- a/apps/web/src/chat/streaming-reply.test.ts
+++ /dev/null
@@ -1,686 +0,0 @@
-import { describe, expect, test } from "bun:test";
-
-import {
-  hydrateStreamingReplyFromTurn,
-  isAwaitingReply,
-  isPendingReply,
-  nextStreamingReplyState,
-  openPendingReply,
-  typingAgentNames,
-  lastHumanMessageParts,
-} from "./streaming-reply";
-
-const HUMAN = { address: "prn_sawyer", handle: "Sawyer" };
-const ADA = { address: "prn_ada@acme.example", handle: "Ada" };
-const MYRA = { address: "myra@agents.example", handle: "Myra" };
-const SCOUT = { address: "scout@agents.example", handle: "Scout" };
-
-function agentEvent(inner: unknown) {
-  return { eventType: "chat.agent", data: inner };
-}
-
-function delta(text: string) {
-  return agentEvent({
-    type: "inference.text.delta",
-    seq: 1,
-    data: { token: text.slice(-1), partial: { text } },
-  });
-}
-
-const AWAITING_EMPTY = { phase: "awaiting", text: "" } as const;
-
-function awaiting(text: string) {
-  return { phase: "awaiting", text } as const;
-}
-
-describe("nextStreamingReplyState (token deltas fold into a growing reply)", () => {
-  test("a non chat.agent event never opens or changes the reply", () => {
-    expect(nextStreamingReplyState(null, { eventType: "chat.typing", data: {} })).toBeNull();
-    const current = awaiting("hi");
-    expect(
-      nextStreamingReplyState(current, {
-        eventType: "chat.pin",
-        data: { type: "inference.text.delta" },
-      }),
-    ).toBe(current);
-  });
-
-  test("inference.start opens an empty in-progress reply", () => {
-    expect(
-      nextStreamingReplyState(
-        null,
-        agentEvent({ type: "inference.start", seq: 0, data: { model: "x" } }),
-      ),
-    ).toEqual(AWAITING_EMPTY);
-  });
-
-  test("inference.start never wipes tokens already streamed", () => {
-    const state = awaiting("Hello");
-    expect(
-      nextStreamingReplyState(
-        state,
-        agentEvent({ type: "inference.start", seq: 9, data: { model: "x" } }),
-      ),
-    ).toBe(state);
-  });
-
-  test("each text delta replaces the reply with that delta's cumulative text", () => {
-    let state = nextStreamingReplyState(
-      null,
-      agentEvent({ type: "inference.start", seq: 0, data: { model: "x" } }),
-    );
-    state = nextStreamingReplyState(state, delta("Hel"));
-    expect(state).toEqual(awaiting("Hel"));
-    state = nextStreamingReplyState(state, delta("Hello"));
-    expect(state).toEqual(awaiting("Hello"));
-  });
-
-  test("inference.done clears the reply — the persisted message takes over", () => {
-    const state = nextStreamingReplyState(
-      awaiting("Hello there"),
-      agentEvent({
-        type: "inference.done",
-        seq: 5,
-        data: { turn: {}, usage: {}, source: "primary" },
-      }),
-    );
-    expect(state).toBeNull();
-  });
-
-  test("inference.done keeps an empty pending reply — the next inference round is still owed", () => {
-    const pending = awaiting("");
-    expect(
-      nextStreamingReplyState(
-        pending,
-        agentEvent({
-          type: "inference.done",
-          seq: 5,
-          data: { turn: {}, usage: {}, source: "primary" },
-        }),
-      ),
-    ).toBe(pending);
-  });
-
-  test("inference.done while idle stays idle — a late done is not a new turn", () => {
-    expect(
-      nextStreamingReplyState(
-        null,
-        agentEvent({
-          type: "inference.done",
-          seq: 5,
-          data: { turn: {}, usage: {}, source: "primary" },
-        }),
-      ),
-    ).toBeNull();
-  });
-
-  test("inference.error clears the reply rather than leaving a stuck cursor", () => {
-    const state = nextStreamingReplyState(
-      awaiting("Hello"),
-      agentEvent({
-        type: "inference.error",
-        seq: 5,
-        data: { error: {}, partial: { text: "Hello" } },
-      }),
-    );
-    expect(state).toBeNull();
-  });
-
-  test("an event with no known inner shape (tool calls, usage) leaves the reply untouched", () => {
-    const state = awaiting("Hello");
-    expect(
-      nextStreamingReplyState(
-        state,
-        agentEvent({
-          type: "inference.tool_call.start",
-          seq: 3,
-          data: { callId: "c1", name: "search", partial: { text: "Hello" } },
-        }),
-      ),
-    ).toBe(state);
-  });
-
-  test("reactor.start opens an empty reply when idle — the turn began before any tokens", () => {
-    expect(
-      nextStreamingReplyState(null, agentEvent({ type: "reactor.start", seq: 0, data: {} })),
-    ).toEqual(AWAITING_EMPTY);
-  });
-
-  test("reactor.start never resets an in-progress reply", () => {
-    const state = awaiting("Hello");
-    expect(
-      nextStreamingReplyState(state, agentEvent({ type: "reactor.start", seq: 9, data: {} })),
-    ).toBe(state);
-  });
-
-  test("reactor.done and reactor.error clear the reply — the whole turn is over", () => {
-    for (const type of ["reactor.done", "reactor.error"]) {
-      expect(
-        nextStreamingReplyState(awaiting("Hello"), agentEvent({ type, seq: 10, data: {} })),
-      ).toBeNull();
-    }
-  });
-
-  test("a malformed delta payload (no partial.text) is ignored rather than crashing", () => {
-    const state = awaiting("Hello");
-    expect(
-      nextStreamingReplyState(
-        state,
-        agentEvent({ type: "inference.text.delta", seq: 2, data: {} }),
-      ),
-    ).toBe(state);
-    expect(nextStreamingReplyState(state, agentEvent(null))).toBe(state);
-    expect(nextStreamingReplyState(state, agentEvent("garbage"))).toBe(state);
-  });
-});
-
-describe("nextStreamingReplyState (the typing pulse clears on a dispatch failure too)", () => {
-  test("a chat.message carrying a turnFailed part clears a pending reply", () => {
-    const state = awaiting("");
-    expect(
-      nextStreamingReplyState(state, {
-        eventType: "chat.message",
-        data: {
-          id: "msg_1",
-          parts: [{ kind: "text", text: "I didn't get that one", turnFailed: true }],
-        },
-      }),
-    ).toBeNull();
-  });
-
-  test("an ordinary chat.message (no turnFailed part) leaves the reply untouched", () => {
-    const state = awaiting("");
-    expect(
-      nextStreamingReplyState(state, {
-        eventType: "chat.message",
-        data: { id: "msg_1", parts: [{ kind: "text", text: "hi" }] },
-      }),
-    ).toBe(state);
-  });
-
-  test("a chat.message with no pending reply stays null", () => {
-    expect(
-      nextStreamingReplyState(null, {
-        eventType: "chat.message",
-        data: { parts: [{ kind: "text", text: "x", turnFailed: true }] },
-      }),
-    ).toBeNull();
-  });
-});
-
-// A user-cancelled turn clears the same pulse a failed one does
-// — `postCancelledNotice` carries `turnCancelled`, not `turnFailed`, so
-// this is its own case rather than reusing the failure fixture above.
-describe("nextStreamingReplyState (the typing pulse clears on a user cancellation too)", () => {
-  test("a chat.message carrying a turnCancelled part settles the turn as replied", () => {
-    const state = awaiting("");
-    expect(
-      nextStreamingReplyState(state, {
-        eventType: "chat.message",
-        data: {
-          id: "msg_1",
-          parts: [
-            {
-              kind: "text",
-              text: "This turn was cancelled.",
-              turnCancelled: true,
-            },
-          ],
-        },
-      }),
-    ).toEqual({ phase: "replied" });
-  });
-
-  test("a chat.message from the cancelled agent's own address is never mistaken for a rendered reply", () => {
-    const state = awaiting("");
-    expect(
-      nextStreamingReplyState(state, {
-        eventType: "chat.message",
-        data: {
-          id: "msg_1",
-          sender: { name: null, address: MYRA.address },
-          parts: [
-            {
-              kind: "text",
-              text: "This turn was cancelled.",
-              turnCancelled: true,
-            },
-          ],
-        },
-      }),
-    ).toEqual({ phase: "replied" });
-  });
-
-  test("inference.start after a turnCancelled notice does not reopen the pulse", () => {
-    let state = nextStreamingReplyState(awaiting("Hello"), {
-      eventType: "chat.message",
-      data: {
-        id: "msg_1",
-        parts: [
-          {
-            kind: "text",
-            text: "This turn was cancelled.",
-            turnCancelled: true,
-          },
-        ],
-      },
-    });
-    state = nextStreamingReplyState(
-      state,
-      agentEvent({ type: "inference.start", seq: 9, data: { model: "x" } }),
-    );
-    expect(isPendingReply(state)).toBe(false);
-    expect(isAwaitingReply(state)).toBe(false);
-  });
-
-  test("a late text delta after a turnCancelled notice does not reopen the pulse", () => {
-    let state = nextStreamingReplyState(awaiting("Hel"), {
-      eventType: "chat.message",
-      data: {
-        id: "msg_1",
-        parts: [
-          {
-            kind: "text",
-            text: "This turn was cancelled.",
-            turnCancelled: true,
-          },
-        ],
-      },
-    });
-    state = nextStreamingReplyState(state, delta("Hello"));
-    expect(isPendingReply(state)).toBe(false);
-    expect(isAwaitingReply(state)).toBe(false);
-  });
-
-  test("reactor.start after a turnCancelled notice does not reopen the pulse", () => {
-    let state = nextStreamingReplyState(awaiting(""), {
-      eventType: "chat.message",
-      data: {
-        id: "msg_1",
-        parts: [
-          {
-            kind: "text",
-            text: "This turn was cancelled.",
-            turnCancelled: true,
-          },
-        ],
-      },
-    });
-    state = nextStreamingReplyState(state, agentEvent({ type: "reactor.start", seq: 0, data: {} }));
-    expect(isPendingReply(state)).toBe(false);
-    expect(isAwaitingReply(state)).toBe(false);
-  });
-});
-
-describe("isAwaitingReply (Stop stays up while tokens stream)", () => {
-  test("is true for the whole awaiting phase, including streamed text", () => {
-    expect(isAwaitingReply(awaiting(""))).toBe(true);
-    expect(isAwaitingReply(awaiting("Hello"))).toBe(true);
-  });
-
-  test("is false when idle or already replied", () => {
-    expect(isAwaitingReply(null)).toBe(false);
-    expect(isAwaitingReply({ phase: "replied" })).toBe(false);
-  });
-
-  test("isPendingReply is only the tokenless pulse — not the Stop predicate", () => {
-    expect(isPendingReply(awaiting("Hello"))).toBe(false);
-    expect(isAwaitingReply(awaiting("Hello"))).toBe(true);
-  });
-});
-
-describe("nextStreamingReplyState (CL-false-no-reply: rendered content, not a lifecycle event, ends the turn)", () => {
-  test("a chat.message from the awaiting turn's agent moves straight to replied — the reply already rendered, connector.reply or not", () => {
-    const state = awaiting("Full answer.");
-    expect(
-      nextStreamingReplyState(state, {
-        eventType: "chat.message",
-        data: {
-          id: "msg_1",
-          sender: { name: null, address: MYRA.address },
-          parts: [{ kind: "text", text: "Full answer." }],
-        },
-      }),
-    ).toEqual({ phase: "replied" });
-  });
-
-  test("a chat.message from the agent's own undelivered-notice address (turnFailed) is never mistaken for a rendered reply", () => {
-    const state = awaiting("");
-    expect(
-      nextStreamingReplyState(state, {
-        eventType: "chat.message",
-        data: {
-          id: "msg_1",
-          sender: { name: null, address: MYRA.address },
-          parts: [{ kind: "text", text: "I didn't get that one", turnFailed: true }],
-        },
-      }),
-    ).toBeNull();
-  });
-
-  test("a chat.message from a human sender never ends the turn — it's not the agent's reply", () => {
-    const state = awaiting("");
-    expect(
-      nextStreamingReplyState(state, {
-        eventType: "chat.message",
-        data: {
-          id: "msg_1",
-          sender: { name: null, address: HUMAN.address },
-          parts: [{ kind: "text", text: "hi" }],
-        },
-      }),
-    ).toBe(state);
-  });
-
-  test("a chat.message with no content parts never ends the turn", () => {
-    const state = awaiting("");
-    expect(
-      nextStreamingReplyState(state, {
-        eventType: "chat.message",
-        data: {
-          id: "msg_1",
-          sender: { name: null, address: MYRA.address },
-          parts: [],
-        },
-      }),
-    ).toBe(state);
-  });
-});
-
-describe("nextStreamingReplyState (a folded run parks after the reply — post-reply tool rounds never re-open the pulse)", () => {
-  test("connector.reply moves the turn to the replied phase — the persisted message takes over the timeline", () => {
-    expect(
-      nextStreamingReplyState(
-        awaiting("Hey! What are you working on right now?"),
-        agentEvent({
-          type: "connector.reply",
-          seq: 9,
-          data: { content: "Hey! What are you working on right now?" },
-        }),
-      ),
-    ).toEqual({ phase: "replied" });
-  });
-
-  test("connector.reply settles an empty pending reply too — the reply is finalized even when its tokens never streamed here", () => {
-    expect(
-      nextStreamingReplyState(
-        awaiting(""),
-        agentEvent({
-          type: "connector.reply",
-          seq: 9,
-          data: { content: "Hey!" },
-        }),
-      ),
-    ).toEqual({ phase: "replied" });
-  });
-
-  test("the replied phase renders nothing — no pulse, no bubble", () => {
-    const replied = nextStreamingReplyState(
-      awaiting(""),
-      agentEvent({ type: "connector.reply", seq: 9, data: { content: "x" } }),
-    );
-    expect(isPendingReply(replied)).toBe(false);
-    expect(typingAgentNames(replied, [HUMAN, MYRA])).toEqual([]);
-  });
-
-  test("message.run.started opens the next turn's pulse — the one event that ends the replied phase from the stream", () => {
-    const replied = nextStreamingReplyState(
-      awaiting(""),
-      agentEvent({ type: "connector.reply", seq: 9, data: { content: "x" } }),
-    );
-    expect(
-      nextStreamingReplyState(
-        replied,
-        agentEvent({ type: "message.run.started", seq: 0, data: {} }),
-      ),
-    ).toEqual(AWAITING_EMPTY);
-  });
-
-  test("message.run.ended returns to idle from any phase — the bracket closed, nothing more streams", () => {
-    for (const state of [awaiting(""), awaiting("Hello")]) {
-      expect(
-        nextStreamingReplyState(
-          state,
-          agentEvent({
-            type: "message.run.ended",
-            seq: 12,
-            data: { status: "completed" },
-          }),
-        ),
-      ).toBeNull();
-    }
-  });
-
-  test("the live Myra sequence: reply posts, memory rounds follow, the run parks — the pulse never comes back", () => {
-    // Captured from a live folded run (scratch stack, real provider): the
-    // run brackets open per dequeued message, the visible reply streams
-    // and posts via connector.reply, then post-reply tool-only rounds
-    // (memory writes) run inference again, and the run PARKS — no
-    // message.run.ended ever arrives.
-    let state = openPendingReply(null);
-    state = nextStreamingReplyState(
-      state,
-      agentEvent({ type: "message.run.started", seq: 0, data: {} }),
-    );
-    state = nextStreamingReplyState(
-      state,
-      agentEvent({ type: "inference.start", seq: 1, data: { model: "x" } }),
-    );
-    expect(isPendingReply(state)).toBe(true);
-    state = nextStreamingReplyState(state, delta("Hey! What are you working on right now?"));
-    state = nextStreamingReplyState(
-      state,
-      agentEvent({
-        type: "inference.done",
-        seq: 4,
-        data: { turn: {}, usage: {}, source: "primary" },
-      }),
-    );
-    state = nextStreamingReplyState(
-      state,
-      agentEvent({
-        type: "connector.reply",
-        seq: 5,
-        data: { content: "Hey! What are you working on right now?" },
-      }),
-    );
-    expect(state).toEqual({ phase: "replied" });
-
-    // Post-reply memory rounds: inference.start must NOT re-open the
-    // pulse, and the textless inference.done must not strand one either.
-    for (const round of [
-      agentEvent({ type: "inference.start", seq: 6, data: { model: "x" } }),
-      agentEvent({
-        type: "inference.tool_call.start",
-        seq: 7,
-        data: { callId: "c1", name: "memory_write" },
-      }),
-      agentEvent({
-        type: "tool.done",
-        seq: 8,
-        data: { result: { callId: "c1", content: [], isError: false } },
-      }),
-      agentEvent({
-        type: "inference.done",
-        seq: 9,
-        data: { turn: {}, usage: {}, source: "primary" },
-      }),
-      agentEvent({ type: "inference.start", seq: 10, data: { model: "x" } }),
-      agentEvent({
-        type: "inference.done",
-        seq: 11,
-        data: { turn: {}, usage: {}, source: "primary" },
-      }),
-    ]) {
-      state = nextStreamingReplyState(state, round);
-      expect(state).toEqual({ phase: "replied" });
-      expect(isPendingReply(state)).toBe(false);
-    }
-    // The run parks here: no message.run.ended, and the state stays
-    // invisible until the next turn's message.run.started.
-  });
-
-  test("the next user turn brings the pulse back — replied never suppresses a genuinely new turn", () => {
-    const replied = nextStreamingReplyState(
-      awaiting(""),
-      agentEvent({ type: "connector.reply", seq: 5, data: { content: "x" } }),
-    );
-    // Locally, the send itself re-opens the pulse...
-    expect(openPendingReply(replied)).toEqual(AWAITING_EMPTY);
-    // ...and on the stream, the dequeued message's own bracket does.
-    let state = nextStreamingReplyState(
-      replied,
-      agentEvent({ type: "message.run.started", seq: 0, data: {} }),
-    );
-    expect(isPendingReply(state)).toBe(true);
-    state = nextStreamingReplyState(
-      state,
-      agentEvent({ type: "inference.start", seq: 1, data: { model: "x" } }),
-    );
-    expect(isPendingReply(state)).toBe(true);
-  });
-});
-
-describe("openPendingReply", () => {
-  test("opens an empty pending reply when idle", () => {
-    expect(openPendingReply(null)).toEqual(AWAITING_EMPTY);
-  });
-
-  test("opens an empty pending reply from a replied previous turn", () => {
-    expect(openPendingReply({ phase: "replied" })).toEqual(AWAITING_EMPTY);
-  });
-
-  test("never resets a reply already streaming", () => {
-    const state = awaiting("Hel");
-    expect(openPendingReply(state)).toBe(state);
-  });
-});
-
-describe("typingAgentNames", () => {
-  test("no active reply means nobody is typing", () => {
-    expect(typingAgentNames(null, [MYRA])).toEqual([]);
-  });
-
-  test("a pending reply with no tokens names the workbench's agent participant", () => {
-    expect(typingAgentNames(awaiting(""), [HUMAN, MYRA])).toEqual(["Myra"]);
-  });
-
-  test("once tokens stream the bubble takes over — the typing line goes quiet", () => {
-    expect(typingAgentNames(awaiting("Hel"), [HUMAN, MYRA])).toEqual([]);
-  });
-
-  test('a slugified handle is shown as a display name — "myra" reads "Myra"', () => {
-    expect(
-      typingAgentNames(awaiting(""), [{ address: "myra@agents.example", handle: "myra" }]),
-    ).toEqual(["Myra"]);
-  });
-
-  test("no agent participant on the workbench means nobody is named", () => {
-    expect(typingAgentNames(awaiting(""), [HUMAN])).toEqual([]);
-  });
-
-  test("a resolved display name wins over the slug-derived one", () => {
-    expect(
-      typingAgentNames(
-        awaiting(""),
-        [HUMAN, MYRA],
-        undefined,
-        new Map([[MYRA.address, "Myra the Helper"]]),
-      ),
-    ).toEqual(["Myra the Helper"]);
-  });
-
-  test("names the mentioned agent, not the first agent on the workbench", () => {
-    const jimmy = { address: "jimmy@agents.example", handle: "jimmy" };
-    expect(
-      typingAgentNames(
-        awaiting(""),
-        [HUMAN, MYRA, jimmy],
-        [{ kind: "text", text: "hey @jimmy take a look" }],
-      ),
-    ).toEqual(["Jimmy"]);
-  });
-
-  test("a 1:1 with no mention still names the only agent", () => {
-    expect(
-      typingAgentNames(awaiting(""), [HUMAN, MYRA], [{ kind: "text", text: "hello" }]),
-    ).toEqual(["Myra"]);
-  });
-
-  test("two agents and no mention names nobody — we do not guess Myra", () => {
-    const jimmy = { address: "jimmy@agents.example", handle: "jimmy" };
-    expect(
-      typingAgentNames(
-        awaiting(""),
-        [HUMAN, MYRA, jimmy],
-        [{ kind: "text", text: "hello everyone" }],
-      ),
-    ).toEqual([]);
-  });
-
-  test("a principal@domain human @mention of Scout among two agents names Scout", () => {
-    expect(
-      typingAgentNames(
-        awaiting(""),
-        [ADA, MYRA, SCOUT],
-        lastHumanMessageParts([
-          {
-            sender: { address: ADA.address },
-            parts: [{ kind: "text", text: "hey @Scout take a look" }],
-          },
-          {
-            sender: { address: SCOUT.address },
-            parts: [{ kind: "text", text: "stream" }],
-            streaming: true,
-          },
-        ]),
-      ),
-    ).toEqual(["Scout"]);
-  });
-});
-
-describe("lastHumanMessageParts", () => {
-  test("returns the latest human message, skipping agents and streaming bubbles", () => {
-    expect(
-      lastHumanMessageParts([
-        {
-          sender: { address: "prn_ada@acme.example" },
-          parts: [{ kind: "text", text: "older" }],
-        },
-        {
-          sender: { address: "prn_ada@acme.example" },
-          parts: [{ kind: "text", text: "hey @Scout" }],
-        },
-        {
-          sender: { address: "scout@agents.example" },
-          parts: [{ kind: "text", text: "on it" }],
-        },
-        {
-          sender: { address: "myra@agents.example" },
-          parts: [{ kind: "text", text: "stream" }],
-          streaming: true,
-        },
-      ]),
-    ).toEqual([{ kind: "text", text: "hey @Scout" }]);
-  });
-
-  test("empty timeline means no addressed parts", () => {
-    expect(lastHumanMessageParts([])).toBeUndefined();
-  });
-});
-
-describe("hydrateStreamingReplyFromTurn (reattach snapshot)", () => {
-  test("no running turn resumes to nothing", () => {
-    expect(hydrateStreamingReplyFromTurn(null)).toBeNull();
-  });
-
-  test("a running turn with committed text opens the reply carrying it", () => {
-    expect(hydrateStreamingReplyFromTurn({ textSnapshot: "streamed so far" })).toEqual(
-      awaiting("streamed so far"),
-    );
-  });
-
-  test("a running turn with no text yet opens the same empty pending pulse as openPendingReply", () => {
-    expect(hydrateStreamingReplyFromTurn({ textSnapshot: null })).toEqual(AWAITING_EMPTY);
-  });
-});
diff --git a/apps/web/src/chat/streaming-reply.ts b/apps/web/src/chat/streaming-reply.ts
deleted file mode 100644
index babd79e16..000000000
--- a/apps/web/src/chat/streaming-reply.ts
+++ /dev/null
@@ -1,487 +0,0 @@
-// The in-progress agent reply, streamed token-by-token: `chat.agent` SSE
-// events already carry the vendored Interchange `InferenceEvent` union
-// verbatim (see `packages/chat/src/platform-adapter.ts`'s
-// `subscribeToWorkbench`, which wraps `sidecarRouter.subscribeAgent`'s raw
-// callback payload with no filtering) — this module is the trust boundary
-// that narrows that `unknown` payload and the pure state machine that turns
-// a run of `inference.text.delta` events into one growing string.
-//
-// `inference.text.delta`'s `data.partial.text` is already cumulative (see
-// `PartialMessage` in `@intx/types/src/runtime.ts`) — each delta is
-// "all text streamed so far," not just the new token — so this module never
-// concatenates fragments itself; it just takes the latest one.
-
-import { useEffect, useRef, useState } from "react";
-
-import { isAgentAddress, mentionedParticipants } from "./wire/mentions";
-import { reportError } from "@corbits/error-sink";
-import type { Part, ParticipantRecord } from "./api";
-import { REAL_CLOCK, type Clock } from "./clock";
-import { displayNameForAddress, type AgentDisplayNames } from "./agent-display-names";
-import { displayNameFromHandle } from "./timeline";
-
-/**
- * The current turn's reply state, phase-tagged:
- *
- * - `"awaiting"` — a turn is in flight and its visible reply hasn't posted
- *   yet: an empty `text` renders the typing pulse, streamed tokens render
- *   the growing bubble.
- * - `"replied"` — this turn's reply has rendered: either its `chat.agent`
- *   stream carried `connector.reply`, or (CL-false-no-reply) its `chat.message`
- *   posted straight from the reply pipeline while awaiting — whichever is
- *   observed first, since a parked folded run's `chat.agent` stream may
- *   never carry the former at all. A live folded run PARKS after the turn
- *   (no `message.run.ended`), and its post-reply tool-only rounds (memory
- *   writes) still emit `inference.start`/`inference.done` — none of which
- *   may re-open the pulse. Renders nothing; only a genuinely new turn
- *   leaves it.
- * - `null` — idle, no turn in flight.
- */
-export type StreamingReplyState =
-  | { readonly phase: "awaiting"; readonly text: string }
-  | { readonly phase: "replied" }
-  | null;
-
-const REPLIED: StreamingReplyState = { phase: "replied" };
-
-function awaiting(text: string): StreamingReplyState {
-  return { phase: "awaiting", text };
-}
-
-/** Whether the state renders the tokenless typing pulse. The `"replied"`
- * phase is deliberately not pending — it renders nothing and must never
- * arm the pending-timeout backstop. */
-export function isPendingReply(state: StreamingReplyState): boolean {
-  return state !== null && state.phase === "awaiting" && state.text === "";
-}
-
-/** Whether a turn is still in flight — Stop stays up for the whole
- * `"awaiting"` phase, including after tokens have started streaming.
- * Distinct from `isPendingReply`, which is only the empty typing pulse. */
-export function isAwaitingReply(state: StreamingReplyState): boolean {
-  return state !== null && state.phase === "awaiting";
-}
-
-type InferenceDeltaEvent = {
-  readonly type: "inference.text.delta";
-  readonly data: { readonly partial: { readonly text: string } };
-};
-
-/** Narrows a `chat.agent` payload down to the one inner event shape this
- * module cares about — every other `InferenceEvent` variant (tool calls,
- * thinking, usage, `inference.start`) is read as its bare `type` string
- * only, never assumed to carry a `partial.text`. */
-function parseInferenceDeltaEvent(data: unknown): InferenceDeltaEvent | null {
-  if (typeof data !== "object" || data === null) return null;
-  const record = data as Record<string, unknown>;
-  if (record.type !== "inference.text.delta") return null;
-  const inner = record.data;
-  if (typeof inner !== "object" || inner === null) return null;
-  const partial = (inner as Record<string, unknown>).partial;
-  if (typeof partial !== "object" || partial === null) return null;
-  const text = (partial as Record<string, unknown>).text;
-  if (typeof text !== "string") return null;
-  return { type: "inference.text.delta", data: { partial: { text } } };
-}
-
-/** The bare `type` discriminant of a `chat.agent` payload, for the two
- * variants that end a turn — read without narrowing the rest of the event,
- * since neither carries (or needs) a `partial.text`. */
-function innerEventType(data: unknown): string | null {
-  if (typeof data !== "object" || data === null) return null;
-  const type = (data as Record<string, unknown>).type;
-  return typeof type === "string" ? type : null;
-}
-
-/** Whether a `chat.message` payload carries `postUndeliveredNotice`'s
- * `turnFailed` part (see `packages/chat/src/workbench-service.ts`). This
- * notice posts straight to the room with no `chat.agent` events at all —
- * the dispatch failed before `sendMail` ever reached the agent — so
- * without this check a turn that fails this way never emits the
- * `reactor.error`/`inference.error` this module otherwise relies on to
- * clear the typing pulse, leaving it stranded until the 120s backstop. */
-function hasTurnFailedPart(data: unknown): boolean {
-  if (typeof data !== "object" || data === null) return false;
-  const parts = (data as Record<string, unknown>).parts;
-  if (!Array.isArray(parts)) return false;
-  return parts.some(
-    (part) =>
-      typeof part === "object" &&
-      part !== null &&
-      (part as Record<string, unknown>).turnFailed === true,
-  );
-}
-
-/** Whether a `chat.message` payload carries `postCancelledNotice`'s
- * `turnCancelled` part (see `packages/chat/src/workbench-service.ts`)
- * — the cancellation counterpart to `hasTurnFailedPart` above,
- * kept as its own flag rather than reusing `turnFailed` because a user
- * stopping a turn is not a failure. Same reasoning applies here: a
- * cancelled turn's dispatch can close with no `chat.agent` events of its
- * own (still waiting on `waitUntilFree`, say), so this notice is the
- * only signal that clears the pulse for that case. */
-function hasTurnCancelledPart(data: unknown): boolean {
-  if (typeof data !== "object" || data === null) return false;
-  const parts = (data as Record<string, unknown>).parts;
-  if (!Array.isArray(parts)) return false;
-  return parts.some(
-    (part) =>
-      typeof part === "object" &&
-      part !== null &&
-      (part as Record<string, unknown>).turnCancelled === true,
-  );
-}
-
-/** Either of the two turn-ended notice flags — the one thing
- * `isRenderedAgentReply` and `nextStreamingReplyState` actually care
- * about ("is this a system notice about how the turn ended, or the
- * agent's own reply"), never which specific outcome it was. */
-function hasTurnEndedNoticePart(data: unknown): boolean {
-  return hasTurnFailedPart(data) || hasTurnCancelledPart(data);
-}
-
-/** Whether a `chat.message` payload is the awaiting turn's own reply
- * actually rendering on screen — the one observable fact this module can
- * trust over any `chat.agent` lifecycle event. `postReply`
- * (`chat-orchestrator.ts`) posts this event from its own dispatch
- * pipeline, entirely separate from the raw `connector.reply` event
- * `chat.agent` otherwise carries — so a dropped, delayed, or (parked
- * folded run) never-sent `connector.reply` can no longer leave the
- * backstop armed once the reply the reader is looking at has already
- * posted. Requires an agent sender (never the reader's own echoed
- * message) and at least one part; `postUndeliveredNotice` also posts from
- * the agent's own address with a real text part, so
- * `hasTurnEndedNoticePart` rules that one (and its cancelled
- * counterpart) out explicitly rather than by accident. */
-function isRenderedAgentReply(data: unknown): boolean {
-  if (hasTurnEndedNoticePart(data)) return false;
-  if (typeof data !== "object" || data === null) return false;
-  const sender = (data as Record<string, unknown>).sender;
-  if (typeof sender !== "object" || sender === null) return false;
-  const address = (sender as Record<string, unknown>).address;
-  if (typeof address !== "string" || !isAgentAddress(address)) return false;
-  const parts = (data as Record<string, unknown>).parts;
-  return Array.isArray(parts) && parts.length > 0;
-}
-
-/**
- * The streaming reply's whole state machine, pure and turn-phase aware.
- * `message.run.started` — the harness's per-dequeued-
- * message turn begin, the same event the chat orchestrator keys new turns
- * off (see `chat-orchestrator.ts`'s use of `messageRunStarted`) — opens a
- * fresh awaiting turn. While awaiting, `inference.start`/`reactor.start`
- * open the empty pulse (never wiping streamed tokens), each
- * `inference.text.delta` replaces the text with its cumulative snapshot,
- * and a textless `inference.done` keeps the pulse up across pre-reply tool
- * rounds. Two independent signals move the turn to `"replied"`:
- * `connector.reply` on the `chat.agent` stream (the event the orchestrator
- * posts the persisted reply off), and — CL-false-no-reply, since a parked
- * folded run's `chat.agent` stream may never carry that event at all — an
- * awaiting turn's own `chat.message` actually rendering the agent's reply
- * (see `isRenderedAgentReply`). Whichever arrives first wins; the other is
- * then a no-op against an already-`"replied"` turn. A live folded run
- * PARKS after replying (no `message.run.ended`), and its post-reply
- * tool-only rounds (memory writes) still emit `inference.start`/
- * `inference.done`, so in `"replied"` every inference/reactor event is
- * inert rather than re-opening the pulse. The hard-terminal events —
- * `reactor.done`/`reactor.error`, `message.run.ended`, `inference.error`,
- * and a `chat.message` carrying `postUndeliveredNotice`'s `turnFailed`
- * or `postCancelledNotice`'s `turnCancelled` part (see
- * `hasTurnEndedNoticePart`, the failure/cancellation paths with no
- * `chat.agent` events of their own) — return to idle from any phase.
- * A `turnCancelled` notice is the exception: it settles `"replied"` so a
- * late `inference.start` / `reactor.start` / text delta from the still-
- * running occurrence (ceiling) cannot reopen the pulse.
- * Every other event type (tool calls, thinking, usage) leaves the
- * current state untouched.
- */
-export function nextStreamingReplyState(
-  current: StreamingReplyState,
-  event: { readonly eventType: string; readonly data: unknown },
-): StreamingReplyState {
-  if (event.eventType === "chat.message") {
-    if (hasTurnCancelledPart(event.data)) return REPLIED;
-    if (hasTurnFailedPart(event.data)) return null;
-    if (current !== null && current.phase === "awaiting" && isRenderedAgentReply(event.data)) {
-      return REPLIED;
-    }
-    return current;
-  }
-  if (event.eventType !== "chat.agent") return current;
-
-  const innerType = innerEventType(event.data);
-  if (innerType === "message.run.started") return awaiting("");
-  if (
-    innerType === "reactor.done" ||
-    innerType === "reactor.error" ||
-    innerType === "message.run.ended" ||
-    innerType === "inference.error"
-  ) {
-    return null;
-  }
-  if (innerType === "connector.reply") return REPLIED;
-  if (current !== null && current.phase === "replied") return current;
-
-  if (innerType === "inference.start") return current ?? awaiting("");
-  // `reactor.start` is the earliest "the agent is on it" signal — it
-  // fires before any tokens, often seconds before a slow model's
-  // `inference.start` — so it opens the indicator without waiting for
-  // the first inference call.
-  if (innerType === "reactor.start") return current ?? awaiting("");
-  if (innerType === "inference.done") {
-    if (current === null || current.text === "") return current;
-    return null;
-  }
-
-  const delta = parseInferenceDeltaEvent(event.data);
-  if (delta === null) return current;
-  return awaiting(delta.data.partial.text);
-}
-
-/**
- * Owns the streaming reply's state end to end: feed it every stream event
- * (`chat-workspace.tsx` already sees them all, same as
- * `useTypingIndicator`) and it tracks the active turn's growing text,
- * clearing itself the moment the turn ends. `workbenchId` resets it
- * immediately on a workbench switch, same reasoning as
- * `useTypingIndicator` — an in-progress reply from the workbench just left
- * belongs to that workbench's timeline, not the new one.
- */
-/**
- * Opens an empty pending reply without an agent event: the caller just
- * sent a message to a workbench with an agent in it, so a reply is owed
- * even though no `reactor.start` has streamed yet. Never resets a reply
- * already streaming.
- */
-export function openPendingReply(current: StreamingReplyState): StreamingReplyState {
-  // A `"replied"` previous turn is over — the send that called this opens
-  // the next one, so the pulse comes back.
-  if (current === null || current.phase === "replied") return awaiting("");
-  return current;
-}
-
-/**
- * The catch-up snapshot a client reattaching mid-turn (a fresh mount after
- * navigating away and back) hydrates its streaming reply with,
- * before the live SSE tail resumes: a running turn with committed text
- * opens the reply already carrying it; a running turn with none yet (still
- * in its first inference call) opens the same empty pending state
- * `openPendingReply` would; no running turn at all means there's nothing to
- * resume. Never called once a live event has already produced state — see
- * `resumeFromTurn`'s own guard below.
- */
-export function hydrateStreamingReplyFromTurn(
-  runningTurn: { readonly textSnapshot?: string | null } | null,
-): StreamingReplyState {
-  if (runningTurn === null) return null;
-  return awaiting(runningTurn.textSnapshot ?? "");
-}
-
-/** How long a turn may go without a single new token before it's declared
- * dead — the backstop for both a turn whose stream events never arrive at
- * all (agent down, SSE dropped mid-reconnect) and one that starts streaming
- * and then stalls (model OOM, dropped Ollama connection, sidecar crash: all
- * routine with local models). This measures the gap *since the
- * last token*, not total turn duration — a healthy local model can
- * legitimately run 200s+ end to end (round 1 measured ~216s on
- * `qwen3.8:27b`), so a total-elapsed timeout would fire on working replies.
- * 120s of dead air with zero new output, on the other hand, is never a
- * healthy sign even for a slow model — it's long past any single decode
- * step, tool round-trip, or reconnect a client is expected to ride out. */
-const PENDING_REPLY_CLEAR_MS = 120_000;
-
-/** Floor on how long the empty typing pulse stays up after it first
- * appears. Fast models can emit `inference.start` + first token in the
- * same tick; without this the bubble flashes and vanishes. */
-const TYPING_INDICATOR_MIN_VISIBLE_MS = 700;
-
-export function useStreamingReply(
-  workbenchId: string | null,
-  clearMs: number = PENDING_REPLY_CLEAR_MS,
-  minVisibleMs: number = TYPING_INDICATOR_MIN_VISIBLE_MS,
-  clock: Clock = REAL_CLOCK,
-): {
-  readonly streamingReply: StreamingReplyState;
-  /** Set once the backstop above has fired for the turn just cleared — a
-   * `reportError` refId the host's honest notice quotes, the
-   * same "ref id + Retry" treatment `postUndeliveredNotice`
-   * (the hub's chat routes) gives a dispatch failure that surfaces server-side.
-   * This is the same class of failure with no server signal at all (a
-   * cold-waking agent that never streams back a token), so it deserves
-   * the same backstop rather than the ref-less, action-less notice this
-   * used to render. `null` when idle. Reset on the next workbench switch,
-   * stream event, or awaited reply, same lifecycle as `streamingReply`
-   * itself. */
-  readonly replyTimedOutRefId: string | null;
-  readonly handleStreamEvent: (eventType: string, data: unknown) => void;
-  readonly noteAwaitingReply: () => void;
-  /** See `resumeFromTurn`'s own doc comment below. */
-  readonly resumeFromTurn: (runningTurn: { readonly textSnapshot?: string | null } | null) => void;
-} {
-  const [streamingReply, setStreamingReply] = useState<StreamingReplyState>(null);
-  const [replyTimedOutRefId, setReplyTimedOutRefId] = useState<string | null>(null);
-  const pendingSinceRef = useRef<number | null>(null);
-  const holdTimerRef = useRef<unknown>(null);
-
-  useEffect(() => {
-    setStreamingReply(null);
-    setReplyTimedOutRefId(null);
-    pendingSinceRef.current = null;
-    if (holdTimerRef.current !== null) {
-      clock.clearTimeout(holdTimerRef.current);
-      holdTimerRef.current = null;
-    }
-  }, [workbenchId, clock]);
-
-  useEffect(() => {
-    // Arm for the whole "awaiting" phase, not just its tokenless prefix
-    //: a token still growing the reply is not evidence the turn
-    // is alive forever, only that it was alive as of that token. Every
-    // token produces a new `streamingReply` object (see `awaiting`), so
-    // this effect's own dependency below tears down the previous timer and
-    // arms a fresh one on each token — the window this constructs is
-    // therefore inter-token silence, never total elapsed time.
-    if (streamingReply === null || streamingReply.phase !== "awaiting") {
-      return;
-    }
-    const timer = clock.setTimeout(() => {
-      // The dependency below re-arms this effect (clearing this exact
-      // timer) the instant `streamingReply` changes, so this callback only
-      // ever runs while it's still the same pending reply it was armed
-      // for — no need to re-check identity here.
-      const refId = reportError(
-        new Error(
-          `Reply timed out: no token received within ${clearMs}ms` +
-            (workbenchId !== null ? ` for workbench ${workbenchId}` : ""),
-        ),
-        {
-          operation: "chat.replyTimedOut",
-          ...(workbenchId !== null ? { roomId: workbenchId } : {}),
-        },
-      );
-      setStreamingReply(null);
-      setReplyTimedOutRefId(refId);
-      pendingSinceRef.current = null;
-    }, clearMs);
-    return () => clock.clearTimeout(timer);
-  }, [streamingReply, clearMs, workbenchId, clock]);
-
-  function commitReply(
-    next: StreamingReplyState,
-    current: StreamingReplyState,
-  ): StreamingReplyState {
-    const now = clock.now();
-    const becamePending = isPendingReply(next) && !isPendingReply(current);
-    if (becamePending) pendingSinceRef.current = now;
-
-    const leavingPending = isPendingReply(current) && !isPendingReply(next);
-    if (
-      leavingPending &&
-      pendingSinceRef.current !== null &&
-      now - pendingSinceRef.current < minVisibleMs
-    ) {
-      if (holdTimerRef.current !== null) clock.clearTimeout(holdTimerRef.current);
-      const remaining = minVisibleMs - (now - pendingSinceRef.current);
-      const held = next;
-      holdTimerRef.current = clock.setTimeout(() => {
-        holdTimerRef.current = null;
-        pendingSinceRef.current = null;
-        setStreamingReply(held);
-      }, remaining);
-      return current;
-    }
-
-    if (holdTimerRef.current !== null) {
-      clock.clearTimeout(holdTimerRef.current);
-      holdTimerRef.current = null;
-    }
-    if (!isPendingReply(next)) pendingSinceRef.current = null;
-    return next;
-  }
-
-  function handleStreamEvent(eventType: string, data: unknown) {
-    setReplyTimedOutRefId(null);
-    setStreamingReply((current) =>
-      commitReply(nextStreamingReplyState(current, { eventType, data }), current),
-    );
-  }
-
-  function noteAwaitingReply() {
-    setReplyTimedOutRefId(null);
-    setStreamingReply((current) => commitReply(openPendingReply(current), current));
-  }
-
-  /**
-   * Applies a fetched turn-state snapshot (see `api.ts`'s
-   * `fetchRunningTurn`) on a fresh mount, before any live event has
-   * arrived. Guarded to only ever fill an empty (`null`) state — a stream
-   * event that already opened or grew the reply always wins, since it is
-   * strictly newer than a snapshot fetched moments earlier over a separate
-   * request. A `null` turn (nothing running) is a no-op, not a reset: it
-   * must never clear a reply a fast SSE `reactor.start` already opened
-   * while the snapshot fetch was in flight.
-   */
-  function resumeFromTurn(runningTurn: { readonly textSnapshot?: string | null } | null) {
-    if (runningTurn === null) return;
-    setReplyTimedOutRefId(null);
-    setStreamingReply((current) => current ?? hydrateStreamingReplyFromTurn(runningTurn));
-  }
-
-  return {
-    streamingReply,
-    replyTimedOutRefId,
-    handleStreamEvent,
-    noteAwaitingReply,
-    resumeFromTurn,
-  };
-}
-
-/**
- * The handle(s) to show as "typing" in the incoming-message slot while a reply is
- * owed but no tokens have streamed yet. Names the agent the latest human
- * message addressed (`@handle`); a 1:1 with no mention still names that
- * one agent. Two or more agents and no mention names nobody — guessing
- * the workbench's first participant is how "Myra is typing" lied while
- * Scout was the one asked.
- */
-export function typingAgentNames(
-  streamingReply: StreamingReplyState,
-  participants: readonly ParticipantRecord[],
-  parts?: readonly Part[],
-  displayNames?: AgentDisplayNames,
-): readonly string[] {
-  if (!isPendingReply(streamingReply)) return [];
-  const agents = participants.filter((participant) => isAgentAddress(participant.address));
-  if (agents.length === 0) return [];
-
-  const addressed = parts === undefined ? [] : mentionedParticipants(parts, participants);
-  const named =
-    addressed.length > 0
-      ? agents.filter((agent) => addressed.includes(agent.address))
-      : agents.length === 1
-        ? agents
-        : [];
-  return named.map(
-    (agent) =>
-      displayNameForAddress(agent.address, displayNames) ?? displayNameFromHandle(agent.handle),
-  );
-}
-
-/** The latest human (non-agent, non-streaming) message's parts — what
- * `typingAgentNames` uses to see who was addressed. */
-export function lastHumanMessageParts(
-  items: readonly {
-    readonly sender: { readonly address: string };
-    readonly parts: readonly Part[];
-    readonly streaming?: boolean;
-  }[],
-): readonly Part[] | undefined {
-  for (let i = items.length - 1; i >= 0; i--) {
-    const item = items[i];
-    if (item === undefined) continue;
-    if (item.streaming === true) continue;
-    if (isAgentAddress(item.sender.address)) continue;
-    return item.parts;
-  }
-  return undefined;
-}
diff --git a/apps/web/src/chat/thread-feed.test.ts b/apps/web/src/chat/thread-feed.test.ts
deleted file mode 100644
index a94fc384e..000000000
--- a/apps/web/src/chat/thread-feed.test.ts
+++ /dev/null
@@ -1,157 +0,0 @@
-import { describe, expect, test } from "bun:test";
-import type { MessageItem } from "./api";
-import { selectThreadFeed, threadAffordanceMeta, type ThreadActivityRow } from "./thread-feed";
-
-function message(
-  id: string,
-  threadId: string | undefined,
-  overrides?: Partial<MessageItem>,
-): MessageItem {
-  return {
-    id,
-    createdAt: `2026-08-19T10:00:0${id}Z`,
-    parts: [{ kind: "text", text: id }],
-    sender: { name: null, address: "alice@acme.example" },
-    ...(threadId !== undefined ? { threadId } : {}),
-    ...overrides,
-  };
-}
-
-const ROOT = "thr_root";
-
-describe("selectThreadFeed (one query, filtered by membership)", () => {
-  test("root feed is root-thread membership only", () => {
-    const items = [message("1", ROOT), message("2", "thr_reply"), message("3", ROOT)];
-    const feed = selectThreadFeed(items, {
-      openThreadId: null,
-      parentMessageId: null,
-      rootThreadId: ROOT,
-    });
-    expect(feed.map((m) => m.id)).toEqual(["1", "3"]);
-  });
-
-  test("an open thread shows its own membership with the parent for context", () => {
-    const items = [message("1", ROOT), message("2", "thr_reply"), message("3", "thr_reply")];
-    const feed = selectThreadFeed(items, {
-      openThreadId: "thr_reply",
-      parentMessageId: "1",
-      rootThreadId: ROOT,
-    });
-    expect(feed.map((m) => m.id)).toEqual(["1", "2", "3"]);
-  });
-
-  test("a parent already inside the thread is never duplicated", () => {
-    const items = [message("1", "thr_reply"), message("2", "thr_reply")];
-    const feed = selectThreadFeed(items, {
-      openThreadId: "thr_reply",
-      parentMessageId: "1",
-      rootThreadId: ROOT,
-    });
-    expect(feed.map((m) => m.id)).toEqual(["1", "2"]);
-  });
-
-  test("a brand-new reply thread shows only the message it is being started from", () => {
-    const items = [message("1", ROOT), message("2", ROOT)];
-    const feed = selectThreadFeed(items, {
-      openThreadId: null,
-      parentMessageId: "2",
-      rootThreadId: ROOT,
-    });
-    expect(feed.map((m) => m.id)).toEqual(["2"]);
-  });
-
-  test("a message the host never stamped belongs to the root feed", () => {
-    // No thread store mounted, or a message that predates membership —
-    // the root thread IS the workbench feed, so unstamped is root.
-    const items = [message("1", undefined), message("2", "thr_reply")];
-    expect(
-      selectThreadFeed(items, {
-        openThreadId: null,
-        parentMessageId: null,
-        rootThreadId: ROOT,
-      }).map((m) => m.id),
-    ).toEqual(["1"]);
-  });
-
-  test("with no root thread resolved yet the full mailbox is the feed", () => {
-    const items = [message("1", undefined), message("2", "thr_reply")];
-    expect(
-      selectThreadFeed(items, {
-        openThreadId: null,
-        parentMessageId: null,
-        rootThreadId: "",
-      }).map((m) => m.id),
-    ).toEqual(["1", "2"]);
-  });
-
-  test("output is oldest-first regardless of arrival order", () => {
-    const items = [message("3", ROOT), message("1", ROOT), message("2", ROOT)];
-    expect(
-      selectThreadFeed(items, {
-        openThreadId: null,
-        parentMessageId: null,
-        rootThreadId: ROOT,
-      }).map((m) => m.id),
-    ).toEqual(["1", "2", "3"]);
-  });
-
-  test("a stale open thread id yields an empty feed rather than the wrong one", () => {
-    const items = [message("1", ROOT)];
-    expect(
-      selectThreadFeed(items, {
-        openThreadId: "thr_gone",
-        parentMessageId: null,
-        rootThreadId: ROOT,
-      }),
-    ).toEqual([]);
-  });
-});
-
-describe("threadAffordanceMeta (counts without a request per thread)", () => {
-  const rows: readonly ThreadActivityRow[] = [
-    {
-      id: "thr_reply",
-      kind: "reply",
-      parentMessageId: "1",
-      replyCount: 2,
-      lastActivityAt: "2026-08-19T10:00:03Z",
-    },
-    {
-      id: ROOT,
-      kind: "root",
-      parentMessageId: null,
-      replyCount: 5,
-      lastActivityAt: "2026-08-19T10:00:09Z",
-    },
-  ];
-
-  test("keys reply threads by parent message, with server counts", () => {
-    const meta = threadAffordanceMeta(rows, [
-      message("2", "thr_reply", {
-        sender: { name: null, address: "bob@acme.example" },
-      }),
-      message("3", "thr_reply"),
-    ]);
-    expect(meta.get("1")).toEqual({
-      replyCount: 2,
-      lastActivityAt: "2026-08-19T10:00:03Z",
-      participantAddresses: ["bob@acme.example", "alice@acme.example"],
-    });
-  });
-
-  test("the root thread gets no affordance — it is the feed itself", () => {
-    expect(threadAffordanceMeta(rows, []).has(ROOT)).toBe(false);
-    expect(threadAffordanceMeta(rows, []).size).toBe(1);
-  });
-
-  test("a thread with no parent message is skipped rather than keyed on null", () => {
-    const orphan: ThreadActivityRow = {
-      id: "thr_delivery",
-      kind: "delivery",
-      parentMessageId: null,
-      replyCount: 1,
-      lastActivityAt: null,
-    };
-    expect(threadAffordanceMeta([orphan], []).size).toBe(0);
-  });
-});
diff --git a/apps/web/src/chat/thread-feed.ts b/apps/web/src/chat/thread-feed.ts
deleted file mode 100644
index c5cca25cf..000000000
--- a/apps/web/src/chat/thread-feed.ts
+++ /dev/null
@@ -1,128 +0,0 @@
-// Deriving what the timeline shows from one loaded mailbox.
-//
-// Every message carries the thread it belongs to (`GET /messages` stamps
-// it — see `resolveThreadMembership` in `packages/chat/src/routes.ts`), so
-// "which thread am I looking at" is a filter over data the client already
-// holds, not a different endpoint to call. That is what lets a single
-// query serve the root feed, every open thread, and the reply counts on
-// each thread affordance, instead of a refresh fanning out one request
-// per thread.
-
-import type { MessageItem } from "./api";
-import type { ThreadAffordanceMeta } from "./timeline";
-
-/** The `GET /threads` row fields this module reads. */
-export type ThreadActivityRow = {
-  readonly id: string;
-  readonly kind: "root" | "reply" | "delivery";
-  readonly parentMessageId: string | null;
-  readonly replyCount: number;
-  readonly lastActivityAt: string | null;
-};
-
-export type ThreadFeedView = {
-  readonly openThreadId: string | null;
-  /** The message the open thread hangs off, or — with no `openThreadId`
-   * — the message a reply thread is about to be created from. Either
-   * way it is the context the thread is unreadable without. */
-  readonly parentMessageId: string | null;
-  /** Empty until `GET /threads` resolves one, or on a host with no
-   * thread store at all — either way there is no membership to filter
-   * by, so the whole mailbox is the feed. */
-  readonly rootThreadId: string;
-};
-
-function oldestFirst(items: readonly MessageItem[]): MessageItem[] {
-  return [...items].sort((a, b) =>
-    a.createdAt === b.createdAt ? a.id.localeCompare(b.id) : a.createdAt.localeCompare(b.createdAt),
-  );
-}
-
-/**
- * The root thread IS the workbench feed, so a message carrying no
- * membership belongs to it — the same "root feed by default" contract
- * the server resolves against. Every message reaching the workbench
- * outside `POST /messages` (agent replies, approve blocks, join notices)
- * arrives that way.
- */
-function threadIdOf(item: MessageItem, rootThreadId: string): string {
-  return item.threadId ?? rootThreadId;
-}
-
-/**
- * The messages the timeline renders, oldest-first.
- *
- * An open thread is shown with its parent message prepended: a thread
- * hangs off a message the reader was just looking at, and rendering it
- * without that message strands the conversation context. A brand-new
- * reply thread has no replies yet, so the parent is all there is.
- */
-export function selectThreadFeed(
-  items: readonly MessageItem[],
-  view: ThreadFeedView,
-): MessageItem[] {
-  if (view.openThreadId !== null) {
-    const inThread = oldestFirst(
-      items.filter((item) => threadIdOf(item, view.rootThreadId) === view.openThreadId),
-    );
-    return withParent(inThread, items, view.parentMessageId);
-  }
-  if (view.parentMessageId !== null) {
-    return withParent([], items, view.parentMessageId);
-  }
-  if (view.rootThreadId === "") return oldestFirst(items);
-  return oldestFirst(
-    items.filter((item) => threadIdOf(item, view.rootThreadId) === view.rootThreadId),
-  );
-}
-
-/** A parent that isn't in the loaded page (deleted, or older than the
- * fetched window) degrades to the bare thread rather than an error. */
-function withParent(
-  thread: readonly MessageItem[],
-  all: readonly MessageItem[],
-  parentMessageId: string | null,
-): MessageItem[] {
-  if (parentMessageId === null) return [...thread];
-  if (thread.some((item) => item.id === parentMessageId)) return [...thread];
-  const parent = all.find((item) => item.id === parentMessageId);
-  return parent === undefined ? [...thread] : [parent, ...thread];
-}
-
-/**
- * Reply-thread affordances keyed by the message each thread hangs off.
- * Counts and timestamps come from the `GET /threads` row; only the
- * participant faces are derived from the loaded messages, and both are
- * free of any per-thread request.
- *
- * The root thread is deliberately absent: it is the feed itself, not a
- * thread to open from a message.
- */
-export function threadAffordanceMeta(
-  rows: readonly ThreadActivityRow[],
-  items: readonly MessageItem[],
-): ReadonlyMap<string, ThreadAffordanceMeta> {
-  const addressesByThreadId = new Map<string, string[]>();
-  for (const item of items) {
-    if (item.threadId === undefined) continue;
-    const address = item.sender?.address;
-    if (typeof address !== "string") continue;
-    const current = addressesByThreadId.get(item.threadId);
-    if (current === undefined) {
-      addressesByThreadId.set(item.threadId, [address]);
-    } else if (!current.includes(address)) {
-      current.push(address);
-    }
-  }
-
-  const meta = new Map<string, ThreadAffordanceMeta>();
-  for (const row of rows) {
-    if (row.kind === "root" || row.parentMessageId === null) continue;
-    meta.set(row.parentMessageId, {
-      replyCount: row.replyCount,
-      lastActivityAt: row.lastActivityAt,
-      participantAddresses: addressesByThreadId.get(row.id) ?? [],
-    });
-  }
-  return meta;
-}
diff --git a/apps/web/src/chat/threads-api.ts b/apps/web/src/chat/threads-api.ts
index 477c0662f..c60e8d26f 100644
--- a/apps/web/src/chat/threads-api.ts
+++ b/apps/web/src/chat/threads-api.ts
@@ -335,3 +335,175 @@ export function subscribeToInbox(tenantId: string, onChange: () => void): () =>
     source.close();
   };
 }
+
+// ---------------------------------------------------------------------
+// Rooms: a workbench is a child tenant, and its room conversation is that
+// tenant's mailbox. Reads are the same stock mailbox routes as a chat,
+// scoped to the child tenant id; participants are the child tenant's
+// principals.
+// ---------------------------------------------------------------------
+
+export type RoomParticipant = {
+  readonly id: string;
+  readonly kind: "person" | "agent";
+  readonly name: string;
+  readonly address: string;
+  /** Present for agents: the deployment's anchor run, what a send is
+   * addressed to. */
+  readonly runId?: string;
+};
+
+const PrincipalPage = type({
+  data: type({
+    id: "string",
+    kind: "string",
+    refId: "string",
+    displayName: "string",
+    "email?": "string",
+    status: "string",
+  }).array(),
+  nextCursor: "string | null",
+});
+
+/** Everyone in the room: the child tenant's principals plus its live
+ * deployments' run addresses. A deployment's workflow principal only
+ * appears after its first run, so the run listing is what makes an agent
+ * addressable from the moment it is deployed into the room. */
+export async function listRoomParticipants(tenantId: string): Promise<readonly RoomParticipant[]> {
+  const [page, runs] = await Promise.all([
+    getJson(`/api/tenants/${encodeURIComponent(tenantId)}/principals?limit=100`, PrincipalPage),
+    listChatAgents(tenantId),
+  ]);
+  const people = page.data
+    .filter((principal) => principal.status !== "removed" && principal.kind === "user")
+    .map((principal): RoomParticipant => ({
+      id: principal.id,
+      kind: "person",
+      name: principal.displayName,
+      address: principal.email ?? principal.refId,
+    }));
+  const agents = runs.map((run): RoomParticipant => ({
+    id: run.runId,
+    kind: "agent",
+    name: run.name,
+    address: run.address,
+    runId: run.runId,
+  }));
+  return [...people, ...agents];
+}
+
+export type RoomMessage = {
+  readonly id: string;
+  /** The turn's Message-ID: what a reply in its sub-thread threads onto. */
+  readonly messageId: string;
+  readonly author: "me" | "other";
+  readonly authorName: string;
+  readonly body: string;
+  readonly at: string;
+  /** Native in-reply-to children: the room's sub-threads. */
+  readonly replies: readonly RoomMessage[];
+};
+
+function authorName(address: string): string {
+  const local = address.split("@")[0]?.replace(/^.*</, "") ?? address;
+  return local.length > 0 ? local : address;
+}
+
+type RoomTurn = {
+  readonly id: string;
+  readonly messageId: string;
+  readonly parentId: string | undefined;
+  readonly author: "me" | "other";
+  readonly authorName: string;
+  readonly body: string;
+  readonly at: string;
+};
+
+/** One folder of the room mailbox: the person's own turns live in `Sent`,
+ * everyone else's in `INBOX`. Unlike a chat, a room keeps every message —
+ * a person-to-person turn is as much part of the room as an agent's. */
+async function readRoomFolder(tenantId: string, folder: "INBOX" | "Sent"): Promise<RoomTurn[]> {
+  const page = await getJson(`${mailboxPath(tenantId)}?folder=${folder}&limit=100`, InboxPage);
+  return page.messages.map((message) => ({
+    id: `${folder}:${String(message.uid)}`,
+    messageId: message.envelope.messageId,
+    parentId: message.envelope.inReplyTo ?? message.envelope.references.at(-1),
+    author: folder === "Sent" ? ("me" as const) : ("other" as const),
+    authorName: folder === "Sent" ? "You" : authorName(message.envelope.from),
+    body: frameBody(message.raw),
+    at: message.envelope.date,
+  }));
+}
+
+/** The room timeline: every root turn oldest first, its in-reply-to chain
+ * nested beneath it as the room's sub-threads. */
+export async function readRoom(tenantId: string): Promise<readonly RoomMessage[]> {
+  const [inbox, sent] = await Promise.all([
+    readRoomFolder(tenantId, "INBOX"),
+    readRoomFolder(tenantId, "Sent"),
+  ]);
+  const turns = [...inbox, ...sent].sort((a, b) => Date.parse(a.at) - Date.parse(b.at));
+  const known = new Set(turns.map((turn) => turn.messageId));
+  const children = new Map<string, RoomTurn[]>();
+  const roots: RoomTurn[] = [];
+  for (const turn of turns) {
+    const parentId = turn.parentId;
+    if (parentId === undefined || !known.has(parentId)) {
+      roots.push(turn);
+      continue;
+    }
+    children.set(parentId, [...(children.get(parentId) ?? []), turn]);
+  }
+  const build = (turn: RoomTurn): RoomMessage => ({
+    id: turn.id,
+    messageId: turn.messageId,
+    author: turn.author,
+    authorName: turn.authorName,
+    body: turn.body,
+    at: turn.at,
+    replies: (children.get(turn.messageId) ?? []).map(build),
+  });
+  return roots.map(build);
+}
+
+/** The one send seam for a room: a single mailbox send addressed to every
+ * agent in it. The hub triggers each addressed run and keeps the Sent
+ * copy, so the person's own turn comes back out of the mailbox like any
+ * other. */
+export async function sendToRoom(input: {
+  readonly roomTenantId: string;
+  readonly agents: readonly RoomParticipant[];
+  readonly content: string;
+  /** The turn this reply threads onto — a sub-thread's parent. */
+  readonly inReplyTo?: string;
+}): Promise<void> {
+  const to = input.agents.map((agent) => agent.address).filter((address) => address.includes("@"));
+  if (to.length === 0) {
+    throw new ChatApiError("No agent is in this workbench yet, so there is nobody to send to.");
+  }
+  let response: Response;
+  try {
+    response = await fetch(`${mailboxPath(input.roomTenantId)}/send`, {
+      method: "POST",
+      headers: { "content-type": "application/json" },
+      body: JSON.stringify({
+        to,
+        subject: input.content.slice(0, 60),
+        body: input.content,
+        ...(input.inReplyTo !== undefined ? { inReplyTo: input.inReplyTo } : {}),
+      }),
+    });
+  } catch (cause) {
+    throw new ChatApiError(cause instanceof Error ? cause.message : String(cause));
+  }
+  if (!response.ok) {
+    throw new ChatApiError(
+      `The workbench could not be reached (${String(response.status)}).`,
+      response.status,
+    );
+  }
+  const parsed = SendAccepted(await response.json().catch(() => undefined));
+  if (parsed instanceof type.errors) {
+    throw new ChatApiError(`Unexpected send response: ${parsed.summary}`);
+  }
+}
diff --git a/apps/web/src/chat/timeline.test.ts b/apps/web/src/chat/timeline.test.ts
deleted file mode 100644
index 973c3fe4c..000000000
--- a/apps/web/src/chat/timeline.test.ts
+++ /dev/null
@@ -1,66 +0,0 @@
-import { describe, expect, test } from "bun:test";
-
-import { friendlyEventText } from "./timeline";
-import type { ParticipantRecord } from "./api";
-import type { Part } from "./api";
-
-function agentJoinedPart(address: string): Part & { kind: "event" } {
-  return {
-    kind: "event",
-    event: "workbench.agent-joined",
-    data: { address },
-  };
-}
-
-describe("friendlyEventText — workbench.agent-joined", () => {
-  test("names the agent by its participant handle", () => {
-    const participants: readonly ParticipantRecord[] = [
-      { address: "run_scout@dana.localhost", handle: "scout" },
-    ];
-    expect(friendlyEventText(agentJoinedPart("run_scout@dana.localhost"), participants)).toBe(
-      "Scout joined",
-    );
-  });
-
-  test("falls back to the address's own local part, never a generic noun, when the roster hasn't caught up with this address yet", () => {
-    const participants: readonly ParticipantRecord[] = [
-      { address: "run_myra@dana.localhost", handle: "myra" },
-    ];
-    expect(friendlyEventText(agentJoinedPart("run_scout@dana.localhost"), participants)).toBe(
-      "Run Scout joined",
-    );
-  });
-
-  test("falls back to the generic line only when the event itself carries no address at all", () => {
-    const part: Part & { kind: "event" } = {
-      kind: "event",
-      event: "workbench.agent-joined",
-      data: {},
-    };
-    expect(friendlyEventText(part, [])).toBe("An agent joined");
-  });
-
-  test("prefers the resolved display name over the handle slug", () => {
-    const participants: readonly ParticipantRecord[] = [
-      { address: "run_myra@dana.localhost", handle: "myra" },
-    ];
-    expect(
-      friendlyEventText(
-        agentJoinedPart("run_myra@dana.localhost"),
-        participants,
-        new Map([["run_myra@dana.localhost", "Myra the Helper"]]),
-      ),
-    ).toBe("Myra the Helper joined");
-  });
-});
-
-describe("friendlyEventText — connection.connected", () => {
-  test("names the connected service and points at Tools", () => {
-    const part: Part & { kind: "event" } = {
-      kind: "event",
-      event: "connection.connected",
-      data: { connectorId: "github", displayName: "GitHub" },
-    };
-    expect(friendlyEventText(part, [])).toBe("GitHub connected successfully. Manage in Tools");
-  });
-});
diff --git a/apps/web/src/chat/timeline.tsx b/apps/web/src/chat/timeline.tsx
deleted file mode 100644
index 9b726011a..000000000
--- a/apps/web/src/chat/timeline.tsx
+++ /dev/null
@@ -1,1991 +0,0 @@
-// Renders a workbench's `MessageItem[]` oldest→newest: text parts as chat
-// bubbles, event parts as inline system lines, block parts through the
-// generative-UI block registry, everything else as a labeled fallback
-// block. `sender` is an optional field on `MessageItem` (see
-// api.ts) — a bubble never shows a raw address or instance/principal id: the
-// signed-in user's own messages render as "You" (or their name, from
-// `currentUser`), a sender matching a participant record renders by that
-// record's mention handle (with a visible agent badge when the address is
-// an agent address), and anything else falls back to a deterministic
-// "Member" label with an initials avatar — never the address.
-
-import { isAgentAddress } from "./wire/mentions";
-import {
-  ContextMenuView,
-  contextMenuItem,
-  isContextMenuEmpty,
-  useContextMenuState,
-} from "@/shell/context-menu/lib";
-import type { ContextMenu, ContextMenuEntry } from "@/shell/context-menu/lib";
-import { Avatar, Button, EmptyState, PartsRenderer, toast } from "@corbits/react-ui";
-import { toReactUiReasoning } from "./agent-part-adapter";
-import { displayNameForAddress, type AgentDisplayNames } from "./agent-display-names";
-import { CorbitAvatar, avatarClassForPrincipal } from "./avatar";
-import { groupTimelineParts } from "./tool-activity";
-import { ToolActivityGroup } from "./tool-activity-view";
-import {
-  ArrowBendUpLeft,
-  ArrowDown,
-  ChatCircle,
-  Clock,
-  Copy,
-  DotsThree,
-  PencilSimple,
-} from "@/lib/icons";
-import { memo } from "react";
-import { useEffect, useRef, useState } from "react";
-import type { MouseEvent as ReactMouseEvent, ReactNode } from "react";
-
-import type { MessageItem, MessageSender, ParticipantRecord, Part } from "./api";
-import { ArtifactChip } from "./artifact-chip";
-import type { ApprovalActions } from "./blocks/approval-actions";
-import type { ConnectServiceActions } from "./blocks/connect-service-actions";
-import { BlockPartView } from "./blocks/registry";
-import {
-  CONSUMER_INFERENCE_FAILURE_NOTICE,
-  consumerFacingInferenceText,
-  isClassifiedInferenceFailureText,
-} from "./inference-failure";
-import { WorkbenchLoadingState } from "./loading-state";
-import { Markdown } from "./markdown";
-import type { ProfileSubject } from "./profile-subject";
-import { profileSubjectFromParticipant } from "./profile-subject";
-import { formatRelativeActivity } from "./relative-time";
-import { CHAT_STRINGS } from "./strings";
-import type { FailedTurnModelChoice } from "./failed-turn-models";
-
-/**
- * Which affordance a message's thread row offers:
- * - `"reply"` (root feed) — open/create the depth-1 thread for this message
- * - `"fork"` (inside an open thread) — spawn a sub-thread rooted at this
- *   message, the first-class fork affordance ("something
- *   Slack doesn't have"). The two-level cap is enforced server-side; this
- *   UI never needs to reason about depth itself.
- *
- * No `@/shell/context-menu/lib` message target exists yet (see
- * `apps/web/src/shell/context-menu/targets.ts`) — this row is the
- * fallback surface for both actions until that seam is wired for
- * messages.
- */
-export type ThreadAffordanceMode = "reply" | "fork";
-
-/** The DOM id a message's group renders under. Exported so the host
- * never has to hand-guess the id format. */
-export function messageDomId(messageId: string): string {
-  return `chat-message-${messageId}`;
-}
-
-/**
- * `"sending"` while the host's real request is in flight, `"failed"` once
- * it has rejected. There is no `"sent"` state here — a successful send
- * simply stops being a pending item once the host's next message load
- * folds the real, server-issued message into `items` in its place.
- */
-export type PendingMessageStatus = "sending" | "failed";
-
-/**
- * A message this host has optimistically added to the timeline before
- * (or instead of, on failure) the server confirms it — see
- * `WorkbenchTimeline`'s `items` doc. `nonce` is the host's own client-side
- * key, round-tripped back through `PendingActions` so a retry/discard
- * always targets the exact pending entry the reader acted on, never a
- * position in an array that may have reflowed underneath it.
- */
-export type TimelineMessageItem = MessageItem & {
-  readonly pendingStatus?: PendingMessageStatus;
-  readonly pendingNonce?: string;
-  /** Set on the one synthetic item `mergeStreamingReply`
-   * (`chat-workspace.tsx`) folds onto the end of the timeline while an
-   * agent turn is mid-flight — its text grows as `inference.text.delta`
-   * events arrive and the item disappears the moment the turn ends, see
-   * `useStreamingReply` (`streaming-reply.ts`). Distinct from
-   * `pendingStatus`, which is this reader's own optimistic send: a
-   * streaming item is the *other* side's in-progress reply, rendered
-   * without a hover toolbar, reactions, or pin toggle — none of which make
-   * sense against a message with no server-issued id yet. */
-  readonly streaming?: boolean;
-};
-
-/** The retry/discard round-trip a failed pending bubble's inline actions
- * offer — the host owns both: retry re-sends the same content, discard
- * drops the pending entry and hands its text back to the composer. */
-export type PendingActions = {
-  readonly onRetry: (nonce: string) => void;
-  readonly onDiscard: (nonce: string) => void;
-};
-
-export type CurrentUser = {
-  /**
-   * The signed-in principal's id. A sender address's local part IS the
-   * sending principal's id (the platform builds From as
-   * `<principalId>@<tenant domain>`), so matching on the local part lets
-   * hosts identify "you" without knowing the tenant's mail domain.
-   */
-  readonly principalId: string;
-  readonly name?: string;
-  /**
-   * A handle/email fallback for the own-message avatar's initial when no
-   * `name` is set — never shown as the "You" label itself, only used to
-   * derive a single honest initial (see `ownAvatarInitials`) instead of
-   * running `initialsOf` over the literal word "You".
-   */
-  readonly handle?: string;
-};
-
-/** Fallback glyph for an own-message avatar with no name and no handle to
- * derive an initial from — never a guess, never "YO" from the "You" label
- * itself. */
-const UNKNOWN_INITIAL = "•";
-
-/**
- * The signed-in reader's own avatar initials: `currentUser.name`'s real
- * initials when set, else the first letter of `currentUser.handle`
- * (a mention handle or email — whichever the host had on hand), else
- * `UNKNOWN_INITIAL`. Deliberately never derived from the "You" label
- * itself — `initialsOf("You")` reads as "YO", a fabricated pair of
- * letters with no relationship to the actual signed-in person.
- */
-function ownAvatarInitials(currentUser: CurrentUser): string {
-  if (currentUser.name !== undefined && currentUser.name.trim().length > 0) {
-    return initialsOf(currentUser.name);
-  }
-  const handle = currentUser.handle?.trim();
-  if (handle !== undefined && handle.length > 0) {
-    return handle.charAt(0).toUpperCase();
-  }
-  return UNKNOWN_INITIAL;
-}
-
-export function localPartOf(address: string): string {
-  const at = address.indexOf("@");
-  return at === -1 ? address : address.slice(0, at);
-}
-
-function formatTimestamp(iso: string): string {
-  const date = new Date(iso);
-  if (Number.isNaN(date.getTime())) return iso;
-  return date.toLocaleTimeString([], { hour: "2-digit", minute: "2-digit" });
-}
-
-function isSameCalendarDay(a: Date, b: Date): boolean {
-  return (
-    a.getFullYear() === b.getFullYear() &&
-    a.getMonth() === b.getMonth() &&
-    a.getDate() === b.getDate()
-  );
-}
-
-/**
- * "Today" / "Yesterday" for the two nearby cases, otherwise a medium-length
- * date ("Jan 3, 2026") — never a raw ISO string.
- */
-function formatDayLabel(iso: string): string {
-  const date = new Date(iso);
-  if (Number.isNaN(date.getTime())) return iso;
-
-  const now = new Date();
-  if (isSameCalendarDay(date, now)) return CHAT_STRINGS.dayDividerToday;
-
-  const yesterday = new Date(now);
-  yesterday.setDate(now.getDate() - 1);
-  if (isSameCalendarDay(date, yesterday)) return CHAT_STRINGS.dayDividerYesterday;
-
-  return date.toLocaleDateString([], {
-    month: "short",
-    day: "numeric",
-    year: "numeric",
-  });
-}
-
-/**
- * Two-letter initials for an avatar, derived only from a friendly string
- * already safe to show (a name, a handle, or one of the fallback labels)
- * — never from a raw address or id.
- */
-function initialsOf(source: string): string {
-  const words = source
-    .trim()
-    .split(/\s+/)
-    .filter((word) => word.length > 0);
-  if (words.length === 0) return "?";
-  const first = words[0]?.charAt(0) ?? "";
-  const second = words.length > 1 ? (words[1]?.charAt(0) ?? "") : (words[0]?.charAt(1) ?? "");
-  const initials = `${first}${second}`.toUpperCase();
-  return initials.length > 0 ? initials : "?";
-}
-
-/**
- * A friendly display name from a mention handle — "myra" -> "Myra",
- * "echo-bot" -> "Echo Bot" — for the rare spots (like the join event
- * line) that only have a participant's slugified handle to work with,
- * never a `sender.name`. Never applied to a handle already shown as a
- * literal `@mention` elsewhere.
- */
-export function displayNameFromHandle(handle: string): string {
-  return handle
-    .split(/[-_]+/)
-    .filter((word) => word.length > 0)
-    .map((word) => word.charAt(0).toUpperCase() + word.slice(1))
-    .join(" ");
-}
-
-type SenderDisplay = {
-  readonly label: string;
-  /** The participant's mention handle, when it differs from `label` — a
-   * matched participant's `sender.name` (e.g. "Myra") is what the header
-   * shows now, with the handle (e.g. "myra") surfaced only as a tooltip
-   * rather than lost outright. */
-  readonly handle?: string;
-  readonly isAgent: boolean;
-  readonly initials: string;
-  /** The wire address behind this sender — never shown, only used to pick
-   * a stable per-person fallback color for a human's avatar. */
-  readonly id: string;
-};
-
-function senderDisplay(
-  sender: MessageSender | undefined,
-  participants: readonly ParticipantRecord[],
-  currentUser: CurrentUser | undefined,
-  displayNames?: AgentDisplayNames,
-): SenderDisplay | undefined {
-  if (sender === undefined) return undefined;
-
-  if (currentUser !== undefined && localPartOf(sender.address) === currentUser.principalId) {
-    const label = currentUser.name ?? CHAT_STRINGS.senderYou;
-    return {
-      label,
-      isAgent: false,
-      initials: ownAvatarInitials(currentUser),
-      id: currentUser.principalId,
-    };
-  }
-
-  const matched = participants.find((participant) => participant.address === sender.address);
-  if (matched !== undefined) {
-    const isAgent = isAgentAddress(matched.address);
-    const senderName = sender.name;
-    const wireName = senderName !== null && senderName.trim().length > 0 ? senderName : undefined;
-    // An agent renders its resolved display name — the wire
-    // name when the server sent one, else the `/agents` snapshot's — and
-    // only then falls back to a human reading of its handle ("myra" ->
-    // "Myra"). The raw @handle is a wire identifier, kept to the tooltip
-    // only.
-    const resolvedName =
-      isAgent === true
-        ? (displayNameForAddress(matched.address, displayNames) ?? wireName)
-        : wireName;
-    const label =
-      resolvedName ?? (isAgent ? displayNameFromHandle(matched.handle) : matched.handle);
-    return {
-      label,
-      handle: matched.handle,
-      isAgent,
-      initials: initialsOf(resolvedName ?? matched.handle),
-      id: matched.address,
-    };
-  }
-
-  if (sender.name !== null && sender.name.trim().length > 0) {
-    return {
-      label: sender.name,
-      isAgent: false,
-      initials: initialsOf(sender.name),
-      id: sender.address,
-    };
-  }
-
-  return {
-    label: CHAT_STRINGS.senderFallbackMember,
-    isAgent: false,
-    initials: "?",
-    id: sender.address,
-  };
-}
-
-function SenderAvatar({
-  id,
-  initials,
-  label,
-  isAgent,
-  tenantMonogram,
-  tenantName,
-}: {
-  id: string;
-  initials: string;
-  label: string;
-  isAgent: boolean;
-  tenantMonogram?: string;
-  tenantName?: string;
-}) {
-  return (
-    <span className="sender-avatar-wrap" title={label}>
-      {isAgent ? (
-        <CorbitAvatar ariaLabel={label} size="md" className="sender-avatar" />
-      ) : (
-        <Avatar
-          initials={initials}
-          label={label}
-          tone="neutral"
-          size="md"
-          className={`sender-avatar ${avatarClassForPrincipal(id)}`}
-        />
-      )}
-      {tenantMonogram !== undefined ? (
-        <span className="chat-sender-tenant-badge" title={tenantName} aria-hidden="true">
-          {tenantMonogram}
-        </span>
-      ) : null}
-    </span>
-  );
-}
-
-export function AgentBadge() {
-  return <span className="chat-agent-badge">{CHAT_STRINGS.agentBadgeLabel}</span>;
-}
-
-/** The one visible cue a message this reader just sent is still in
- * flight — reuses the muted-foreground token every other quiet status
- * glyph in this file already sits on, never a bespoke color. */
-function PendingGlyph() {
-  return (
-    <span
-      className="chat-pending-glyph"
-      aria-label={CHAT_STRINGS.pendingSendLabel}
-      title={CHAT_STRINGS.pendingSendLabel}
-    >
-      <Clock aria-hidden="true" />
-    </span>
-  );
-}
-
-function TextBubble({
-  text,
-  createdAt,
-  sender,
-  participants,
-  currentUser,
-  onOpenProfile,
-  onFixConnection,
-  showHeader = true,
-  pendingStatus,
-  pendingNonce,
-  pendingActions,
-  agentDisplayNames,
-}: {
-  text: string;
-  createdAt: string;
-  sender: MessageSender | undefined;
-  participants: readonly ParticipantRecord[];
-  currentUser: CurrentUser | undefined;
-  /** Resolved agent display names — the message header shows
-   * these, never the raw handle slug. */
-  readonly agentDisplayNames?: AgentDisplayNames;
-  onOpenProfile?: (subject: ProfileSubject) => void;
-  onFixConnection?: () => void;
-  /** `false` when this bubble continues an unbroken run of messages from
-   * the same author (see `isGroupedWithPrevious`) — the avatar and
-   * name/timestamp header collapse to a hover-revealed timestamp in the
-   * avatar gutter instead, matching the compact grouped-message pattern
-   * modern chat UIs use rather than repeating the header on every line. */
-  showHeader?: boolean;
-  /** Set while this reader's own send is still in flight or has failed
-   * — the bubble renders exactly like any confirmed
-   * message; `"sending"` only adds `PendingGlyph` next to the timestamp,
-   * `"failed"` appends `PendingFailedRow` inside this same bubble, never
-   * a different layout. */
-  pendingStatus?: PendingMessageStatus;
-  /** The failed bubble's own retry/discard target — see `PendingActions`.
-   * Only read when `pendingStatus === "failed"`. */
-  pendingNonce?: string;
-  pendingActions?: PendingActions;
-}) {
-  const consumerText = consumerFacingInferenceText(text);
-  const display = senderDisplay(sender, participants, currentUser, agentDisplayNames);
-  const isOwn =
-    currentUser !== undefined &&
-    sender !== undefined &&
-    localPartOf(sender.address) === currentUser.principalId;
-  const matched =
-    sender === undefined
-      ? undefined
-      : participants.find((participant) => participant.address === sender.address);
-  const profileSubject = matched !== undefined ? profileSubjectFromParticipant(matched) : null;
-
-  function handleOpenProfile() {
-    if (profileSubject !== null && onOpenProfile !== undefined) {
-      onOpenProfile(profileSubject);
-    }
-  }
-
-  return (
-    <div className="chat-bubble-row" data-own={isOwn} data-grouped={!showHeader}>
-      {showHeader && display !== undefined && (
-        <button
-          type="button"
-          className="sender-avatar-button"
-          aria-label={`${CHAT_STRINGS.profileOpenAction}: ${display.label}`}
-          disabled={profileSubject === null || onOpenProfile === undefined}
-          onClick={handleOpenProfile}
-        >
-          <SenderAvatar
-            id={display.id}
-            initials={display.initials}
-            label={display.label}
-            isAgent={display.isAgent}
-            {...(sender?.tenantMonogram !== undefined
-              ? { tenantMonogram: sender.tenantMonogram }
-              : {})}
-            {...(sender?.tenantName !== undefined ? { tenantName: sender.tenantName } : {})}
-          />
-        </button>
-      )}
-      <div className="chat-bubble" data-pending={pendingStatus}>
-        {showHeader ? (
-          <div className="chat-bubble-head">
-            {display !== undefined && (
-              <button
-                type="button"
-                className="chat-bubble-sender-button"
-                disabled={profileSubject === null || onOpenProfile === undefined}
-                onClick={handleOpenProfile}
-              >
-                <span
-                  className="chat-bubble-sender"
-                  {...(display.handle !== undefined && display.handle !== display.label
-                    ? { title: `@${display.handle}` }
-                    : {})}
-                >
-                  {display.label}
-                  {display.isAgent && <AgentBadge />}
-                </span>
-              </button>
-            )}
-            <span className="chat-bubble-time">{formatTimestamp(createdAt)}</span>
-            {pendingStatus === "sending" ? <PendingGlyph /> : null}
-          </div>
-        ) : (
-          <>
-            <span className="chat-bubble-time-grouped">{formatTimestamp(createdAt)}</span>
-            {pendingStatus === "sending" ? <PendingGlyph /> : null}
-          </>
-        )}
-        <div className="chat-bubble-text">
-          <Markdown text={consumerText} />
-        </div>
-        {onFixConnection !== undefined &&
-          (isClassifiedInferenceFailureText(text) ||
-            consumerText === CONSUMER_INFERENCE_FAILURE_NOTICE) && (
-            <Button
-              type="button"
-              variant="outline"
-              size="sm"
-              className="chat-bubble-fix-connection"
-              onClick={onFixConnection}
-            >
-              {CHAT_STRINGS.fixConnectionAction}
-            </Button>
-          )}
-        {pendingStatus === "failed" && pendingActions !== undefined ? (
-          <PendingFailedRow nonce={pendingNonce ?? ""} pendingActions={pendingActions} />
-        ) : null}
-      </div>
-    </div>
-  );
-}
-
-/**
- * A friendly system line for an event part — never the raw event string on
- * its own and never any address or id out of `part.data`. Known event kinds
- * get a specific line (looking up the matching participant's handle for
- * "workbench.agent-joined" rather than showing the joined agent's address);
- * anything else falls back to the event name with its separators turned
- * into spaces.
- */
-/**
- * The display name a "workbench.agent-joined" event carries, resolved the
- * friendly way: the roster's own handle for that address when the roster
- * knows it, else the address's own local part — never the raw address, and
- * never the generic "An agent joined", which hides a name the event
- * already carries. Undefined only when the event names nobody.
- */
-function joinedAgentName(
-  part: Part & { kind: "event" },
-  participants: readonly ParticipantRecord[],
-  displayNames?: AgentDisplayNames,
-): string | undefined {
-  const data =
-    typeof part.data === "object" && part.data !== null
-      ? (part.data as Record<string, unknown>)
-      : undefined;
-  const address = data !== undefined && typeof data.address === "string" ? data.address : undefined;
-  if (address === undefined) return undefined;
-  const resolved = displayNameForAddress(address, displayNames);
-  if (resolved !== undefined) return resolved;
-  const handle =
-    participants.find((participant) => participant.address === address)?.handle ??
-    localPartOf(address);
-  return displayNameFromHandle(handle);
-}
-
-export function friendlyEventText(
-  part: Part & { kind: "event" },
-  participants: readonly ParticipantRecord[],
-  displayNames?: AgentDisplayNames,
-): string {
-  const data =
-    typeof part.data === "object" && part.data !== null
-      ? (part.data as Record<string, unknown>)
-      : undefined;
-  switch (part.event) {
-    case "workbench.agent-joined": {
-      const name = joinedAgentName(part, participants, displayNames);
-      return name !== undefined
-        ? CHAT_STRINGS.eventAgentJoined(name)
-        : CHAT_STRINGS.eventAgentJoinedUnknown;
-    }
-    case "workbench.membership-changed":
-      return CHAT_STRINGS.eventMembershipChanged;
-    case "workbench.settings-changed": {
-      const changed =
-        data !== undefined && typeof data.changed === "object" && data.changed !== null
-          ? (data.changed as Record<string, unknown>)
-          : undefined;
-      const previous =
-        data !== undefined && typeof data.previous === "object" && data.previous !== null
-          ? (data.previous as Record<string, unknown>)
-          : undefined;
-      const to = changed?.["chat/name"];
-      if (changed !== undefined && Object.keys(changed).length === 1 && typeof to === "string") {
-        const from = previous?.["chat/name"];
-        return typeof from === "string" && from !== to
-          ? CHAT_STRINGS.eventWorkbenchRenamed(from, to)
-          : CHAT_STRINGS.eventWorkbenchRenamedTo(to);
-      }
-      return CHAT_STRINGS.eventSettingsChanged;
-    }
-    case "block.response": {
-      const kind = data !== undefined ? data.kind : undefined;
-      return kind === "poll"
-        ? CHAT_STRINGS.eventBlockResponsePoll
-        : CHAT_STRINGS.eventBlockResponseForm;
-    }
-    case "connection.connected": {
-      const displayName =
-        data !== undefined && typeof data.displayName === "string" ? data.displayName : undefined;
-      return displayName !== undefined
-        ? CHAT_STRINGS.eventConnectionConnected(displayName)
-        : CHAT_STRINGS.eventGeneric(part.event);
-    }
-    default:
-      return CHAT_STRINGS.eventGeneric(part.event);
-  }
-}
-
-function EventLine({
-  part,
-  createdAt,
-  participants,
-  collapsedText,
-  agentDisplayNames,
-}: {
-  part: Part & { kind: "event" };
-  createdAt: string;
-  participants: readonly ParticipantRecord[];
-  /** The one line that stands in for a whole run of consecutive joins —
-   * see `collapseAgentJoinRuns`. Undefined on every other event row. */
-  collapsedText?: string;
-  readonly agentDisplayNames?: AgentDisplayNames;
-}) {
-  const data =
-    typeof part.data === "object" && part.data !== null
-      ? (part.data as Record<string, unknown>)
-      : undefined;
-  const connectedDisplayName =
-    part.event === "connection.connected" &&
-    data !== undefined &&
-    typeof data.displayName === "string"
-      ? data.displayName
-      : undefined;
-
-  return (
-    <div className="chat-event-line">
-      <span>
-        {collapsedText !== undefined ? (
-          collapsedText
-        ) : connectedDisplayName !== undefined ? (
-          <>
-            {CHAT_STRINGS.eventConnectionConnectedBeforeTools(connectedDisplayName)}
-            <a href="/tools">{CHAT_STRINGS.eventConnectionConnectedTools}</a>
-          </>
-        ) : (
-          friendlyEventText(part, participants, agentDisplayNames)
-        )}
-      </span>
-      <span className="chat-event-time">{formatTimestamp(createdAt)}</span>
-    </div>
-  );
-}
-
-/**
- * Host-supplied recovery for a model-unavailable failed turn: tenant
- * chat models for the inline picker, the workbench's agent definition
- * ids, apply (write the capability + refresh) and a real Settings hop.
- */
-export type FailedTurnRecovery = {
-  readonly models: readonly FailedTurnModelChoice[];
-  /** Tool-capable subset for a tools-unsupported recovery. Empty means
-   * the strip still hops to Settings, with no inline picker. */
-  readonly toolCapableModels?: readonly FailedTurnModelChoice[];
-  readonly definitionIdByAddress: Readonly<Record<string, string>>;
-  readonly onApplyModel: (input: {
-    readonly definitionId: string;
-    readonly address: string;
-    readonly canonicalName: string;
-  }) => void | Promise<void>;
-  readonly onOpenAgentSettings: (definitionId: string) => void;
-};
-
-/**
- * The general chat timeline's failed-turn treatment, matching the
- * timeline's own idiom rather than borrowing
- * `PrFailedTurnStrip`'s bordered banner — that component stays as-is for
- * the PR-review surface it was built for, but reusing it here read as a
- * floating alert dropped mid-conversation). A text part
- * `postUndeliveredNotice` posted in its unreachable agent's own voice
- * (`part.turnFailed`) now renders as a quiet inline system row, aligned
- * under the same left gutter every message bubble sits under: muted
- * danger-tinted copy, a small ghost Retry button, and "What happened" as
- * a subtle inline disclosure rather than a second button competing for
- * attention. A named-recovery notice (`turnFailedReason`) replaces
- * Retry with an inline model picker and a real Settings hop.
- * `onRetry`/`onWhatHappened` are the host's own actions; a
- * host that wires neither still gets the row, just with inert controls —
- * matching the fixed-disabled framing every other undefined-action port
- * in this file already falls back to.
- */
-function FailedTurnStrip({
-  item,
-  detailText,
-  retryText,
-  namedRecovery,
-  participants,
-  currentUser,
-  failedTurnRecovery,
-  onRetryFailedTurn,
-  onWhatHappenedFailedTurn,
-  agentDisplayNames,
-}: {
-  readonly item: TimelineMessageItem;
-  /** Resolved agent display names — the strip names the agent
-   * whose turn failed, never its raw handle slug. */
-  readonly agentDisplayNames?: AgentDisplayNames;
-  /** The undelivered-turn notice's own text (`postUndeliveredNotice`,
-   * the hub's chat routes) — already cause-aware server-side (a missing model
-   * credential reads "add or check your model key," a generic dispatch
-   * failure reads "send it again"). Shown as this strip's own detail
-   * rather than the fixed `turnFailedSub` string, so the person reads
-   * the real diagnosis instead of a guess. Falls back to `turnFailedSub`
-   * only when the notice carries no text at all. */
-  readonly detailText: string;
-  /** The original message this turn never answered, recovered by
-   * `findRetryText` — handed to `onRetryFailedTurn` so Retry has
-   * something to resend rather than nothing. */
-  readonly retryText?: string;
-  readonly namedRecovery?: "model_unavailable" | "tools_unsupported";
-  readonly participants: readonly ParticipantRecord[];
-  readonly currentUser: CurrentUser | undefined;
-  readonly failedTurnRecovery?: FailedTurnRecovery;
-  readonly onRetryFailedTurn?: (
-    item: TimelineMessageItem,
-    retryText?: string,
-  ) => void | Promise<void>;
-  readonly onWhatHappenedFailedTurn?: (item: TimelineMessageItem) => void;
-}) {
-  const display = senderDisplay(item.sender, participants, currentUser, agentDisplayNames);
-  const sender = display?.label ?? CHAT_STRINGS.senderFallbackMember;
-  const consumerDetail = consumerFacingInferenceText(detailText);
-  const [expanded, setExpanded] = useState(false);
-  // Guards the resend itself against a double-click firing two sends —
-  // not composer state, since Retry never touches the composer any more.
-  const [retrying, setRetrying] = useState(false);
-  const definitionId = failedTurnRecovery?.definitionIdByAddress[item.sender.address];
-
-  if (namedRecovery !== undefined) {
-    const recoveryTitle =
-      namedRecovery === "tools_unsupported"
-        ? CHAT_STRINGS.turnFailedToolsUnsupported(sender)
-        : CHAT_STRINGS.turnFailedModelUnavailable(sender);
-    const pickerModels =
-      namedRecovery === "tools_unsupported"
-        ? (failedTurnRecovery?.toolCapableModels ?? [])
-        : (failedTurnRecovery?.models ?? []);
-    return (
-      <div className="chat-turn-failed" role="status">
-        <span className="chat-turn-failed-text">{recoveryTitle}</span>
-        {failedTurnRecovery !== undefined &&
-        definitionId !== undefined &&
-        pickerModels.length > 0 ? (
-          <select
-            className="chat-turn-failed-models"
-            aria-label={CHAT_STRINGS.turnFailedPickModel}
-            disabled={retrying}
-            defaultValue=""
-            onChange={async (event) => {
-              const canonicalName = event.target.value;
-              if (canonicalName === "" || retrying) return;
-              setRetrying(true);
-              try {
-                await failedTurnRecovery.onApplyModel({
-                  definitionId,
-                  address: item.sender.address,
-                  canonicalName,
-                });
-                await onRetryFailedTurn?.(item, retryText);
-              } finally {
-                setRetrying(false);
-              }
-            }}
-          >
-            <option value="" disabled>
-              {CHAT_STRINGS.turnFailedPickModel}
-            </option>
-            {pickerModels.map((model) => (
-              <option key={model.canonicalName} value={model.canonicalName}>
-                {model.label}
-              </option>
-            ))}
-          </select>
-        ) : null}
-        {failedTurnRecovery !== undefined && definitionId !== undefined ? (
-          <button
-            type="button"
-            className="chat-turn-failed-settings"
-            onClick={() => failedTurnRecovery.onOpenAgentSettings(definitionId)}
-          >
-            {CHAT_STRINGS.turnFailedMoreInSettings}
-          </button>
-        ) : null}
-      </div>
-    );
-  }
-
-  return (
-    <div className="chat-turn-failed" role="status">
-      <span className="chat-turn-failed-text">{CHAT_STRINGS.turnFailedTitle(sender)}</span>
-      <Button
-        type="button"
-        variant="ghost"
-        size="sm"
-        className="chat-turn-failed-retry"
-        disabled={retrying}
-        onClick={() => {
-          if (retrying) return;
-          setRetrying(true);
-          void Promise.resolve(onRetryFailedTurn?.(item, retryText)).finally(() =>
-            setRetrying(false),
-          );
-        }}
-      >
-        {CHAT_STRINGS.prThreadRetryAction}
-      </Button>
-      <button
-        type="button"
-        className="chat-turn-failed-disclosure"
-        aria-expanded={expanded}
-        onClick={() => {
-          setExpanded((open) => !open);
-          onWhatHappenedFailedTurn?.(item);
-        }}
-      >
-        {CHAT_STRINGS.prThreadWhatHappenedAction}
-      </button>
-      {expanded ? (
-        <span className="chat-turn-failed-detail">
-          {consumerDetail.length > 0 ? consumerDetail : CHAT_STRINGS.turnFailedSub}
-        </span>
-      ) : null}
-    </div>
-  );
-}
-
-/**
- * The cancelled-turn counterpart to `FailedTurnStrip` — same
- * quiet inline placement, deliberately simpler: no Retry (the user
- * chose to stop this; resending is just typing again, not recovering
- * from an error) and no disclosure, since `postCancelledNotice`'s own
- * text ("This turn was cancelled.") is the whole story — there is no
- * hidden diagnosis to expand into, unlike a failure's cause.
- */
-function CancelledTurnStrip({
-  item,
-  participants,
-  currentUser,
-  agentDisplayNames,
-}: {
-  readonly item: TimelineMessageItem;
-  readonly participants: readonly ParticipantRecord[];
-  readonly currentUser: CurrentUser | undefined;
-  readonly agentDisplayNames?: AgentDisplayNames;
-}) {
-  const display = senderDisplay(item.sender, participants, currentUser, agentDisplayNames);
-  const sender = display?.label ?? CHAT_STRINGS.senderFallbackMember;
-  return (
-    <div className="chat-turn-cancelled" role="status">
-      <span>{CHAT_STRINGS.turnCancelledTitle(sender)}</span>
-    </div>
-  );
-}
-
-/**
- * The nearest message before a failed-turn notice sent by someone other
- * than the unreachable agent itself — the request that notice answered.
- * `postUndeliveredNotice` posts the notice from that agent's own address
- * right after the dispatch it was answering, so walking backward from
- * the notice to the first message from a different sender finds that
- * request without the wire needing to carry an explicit back-reference.
- * Undefined when nothing precedes it (a notice at the very top of what's
- * loaded) — Retry then has nothing to hand back, same as before this
- * existed.
- */
-export function findRetryText(
-  items: readonly TimelineMessageItem[],
-  failedItem: TimelineMessageItem,
-): string | undefined {
-  const index = items.findIndex((candidate) => candidate.id === failedItem.id);
-  if (index === -1) return undefined;
-  for (let i = index - 1; i >= 0; i -= 1) {
-    const candidate = items[i];
-    if (candidate === undefined) continue;
-    if (candidate.sender.address === failedItem.sender.address) continue;
-    const text = candidate.parts
-      .filter((part): part is Part & { kind: "text" } => part.kind === "text")
-      .map((part) => part.text)
-      .join("");
-    return text.length > 0 ? text : undefined;
-  }
-  return undefined;
-}
-
-function FallbackPart({ part }: { part: Part }) {
-  return (
-    <div className="chat-fallback-block">
-      <span className="chat-fallback-label">{CHAT_STRINGS.fallbackPartLabel(part.kind)}</span>
-      <span className="chat-fallback-body">{CHAT_STRINGS.fallbackPartUnsupported}</span>
-    </div>
-  );
-}
-
-/**
- * A file part shows only its name and media type — never the base64 payload
- * or blob id, which are transport details rather than something a reader
- * should see in the timeline. Rendered as the mock's artifact chip; see
- * `artifact-chip.tsx` for when it opens versus stays inert.
- */
-function FilePartView({
-  part,
-  onOpenArtifact,
-  onOpenArtifactInLibrary,
-}: {
-  part: Part & { kind: "file" };
-  onOpenArtifact?: (part: Part & { kind: "file" }) => void;
-  onOpenArtifactInLibrary?: (part: Part & { kind: "file" }) => void;
-}) {
-  return (
-    <ArtifactChip
-      part={part}
-      {...(onOpenArtifact !== undefined ? { onOpen: onOpenArtifact } : {})}
-      {...(onOpenArtifactInLibrary !== undefined
-        ? { onOpenInLibrary: onOpenArtifactInLibrary }
-        : {})}
-    />
-  );
-}
-
-function DayDivider({ createdAt }: { createdAt: string }) {
-  return (
-    <div className="chat-day-divider">
-      <span>{formatDayLabel(createdAt)}</span>
-    </div>
-  );
-}
-
-async function copyMessageText(text: string): Promise<void> {
-  try {
-    await navigator.clipboard.writeText(text);
-    toast(CHAT_STRINGS.copyTextCopiedToast);
-  } catch {
-    toast(CHAT_STRINGS.copyTextError);
-  }
-}
-
-export function messageText(item: MessageItem): string {
-  return item.parts
-    .filter((part): part is Part & { kind: "text" } => part.kind === "text")
-    .map((part) => part.text)
-    .join("\n");
-}
-
-/**
- * Whether a timeline row should expose message social chrome —
- * add-reaction, reply-in-thread, overflow/ellipsis, reaction chips, and the
- * thread-summary affordance. System event lines, failed-turn strips,
- * connect cards, and classified inference-failure bubbles are not
- * conversational messages; reacting to "Scout joined" or pinning a
- * connect-github card is noise. Fix-this-connection recovery on a
- * classified failure lives on the bubble itself (`TextBubble`) and is
- * independent of this gate.
- */
-export function offersMessageSocialChrome(item: MessageItem): boolean {
-  if (item.parts.length === 0) return false;
-  return !item.parts.every((part) => {
-    if (part.kind === "event") return true;
-    if (part.kind === "text" && part.turnFailed === true) return true;
-    if (part.kind === "text" && part.turnCancelled === true) return true;
-    if (
-      part.kind === "text" &&
-      (isClassifiedInferenceFailureText(part.text) ||
-        part.text === CONSUMER_INFERENCE_FAILURE_NOTICE)
-    ) {
-      return true;
-    }
-    if (part.kind === "block") {
-      return part.block.type === "connect-github" || part.block.type === "connect-service";
-    }
-    return false;
-  });
-}
-
-/**
- * System notices (event-only rows) are never "own" for any viewer —
- * see DESIGN.md's Message Alignment section. Join / rename / membership
- * lines often carry the acting principal as `sender`, but they still
- * align left; treating them as own put them on the signed-in user's
- * right edge.
- */
-export function isSystemNoticeItem(item: MessageItem): boolean {
-  return item.parts.length > 0 && item.parts.every((part) => part.kind === "event");
-}
-
-/**
- * A message posted in the room's own voice rather than by any member —
- * the `system@` sender the room's onboarding card arrives under. Such a
- * row is never "own" for any viewer and never carries author chrome: it
- * is the room talking, not a person.
- */
-export function isSystemSenderItem(item: MessageItem): boolean {
-  return item.sender !== undefined && localPartOf(item.sender.address) === "system";
-}
-
-/** The display name a lone agent-joined row names, or undefined when the
- * item is anything else. */
-function agentJoinName(
-  item: TimelineMessageItem,
-  participants: readonly ParticipantRecord[],
-  displayNames?: AgentDisplayNames,
-): string | undefined {
-  if (item.parts.length !== 1) return undefined;
-  const part = item.parts[0];
-  if (part === undefined || part.kind !== "event" || part.event !== "workbench.agent-joined") {
-    return undefined;
-  }
-  return joinedAgentName(part, participants, displayNames);
-}
-
-/**
- * A room whose whole team arrives at once used to open on a stack of
- * "X joined / Y joined / Z joined" — the first thing a person read was a
- * membership log. Consecutive joins with nothing between them collapse
- * into a single line naming everyone; joins separated by a real message
- * stay their own rows, because there the sequence is the point.
- *
- * Returns the line to render on each run's first item, and the ids of the
- * items that line already accounts for.
- */
-export function collapseAgentJoinRuns(
-  items: readonly TimelineMessageItem[],
-  participants: readonly ParticipantRecord[],
-  displayNames?: AgentDisplayNames,
-): {
-  readonly textByLeadId: ReadonlyMap<string, string>;
-  readonly absorbedIds: ReadonlySet<string>;
-} {
-  const textByLeadId = new Map<string, string>();
-  const absorbedIds = new Set<string>();
-  let index = 0;
-  while (index < items.length) {
-    const names: string[] = [];
-    let end = index;
-    while (end < items.length) {
-      const item = items[end];
-      if (item === undefined) break;
-      const name = agentJoinName(item, participants, displayNames);
-      if (name === undefined) break;
-      names.push(name);
-      end += 1;
-    }
-    if (names.length > 1) {
-      const lead = items[index];
-      if (lead !== undefined) {
-        textByLeadId.set(lead.id, CHAT_STRINGS.eventAgentsJoined(names));
-        for (const absorbed of items.slice(index + 1, end)) {
-          absorbedIds.add(absorbed.id);
-        }
-      }
-    }
-    index = end > index ? end : index + 1;
-  }
-  return { textByLeadId, absorbedIds };
-}
-
-/**
- * A failed send's inline recovery row: appended below
- * the bubble text of the exact same message group a confirmed message
- * would render as — never a status line elsewhere on the page,
- * disconnected from the message it describes.
- */
-function PendingFailedRow({
-  nonce,
-  pendingActions,
-}: {
-  readonly nonce: string;
-  readonly pendingActions: PendingActions;
-}) {
-  return (
-    <div className="chat-pending-failed-row" role="alert">
-      <span className="chat-pending-failed-label">{CHAT_STRINGS.pendingSendFailedLabel}</span>
-      <Button
-        type="button"
-        variant="ghost"
-        size="sm"
-        className="chat-pending-retry"
-        onClick={() => pendingActions.onRetry(nonce)}
-      >
-        {CHAT_STRINGS.pendingSendRetryAction}
-      </Button>
-      <Button
-        type="button"
-        variant="ghost"
-        size="sm"
-        className="chat-pending-discard"
-        onClick={() => pendingActions.onDiscard(nonce)}
-      >
-        {CHAT_STRINGS.pendingSendDiscardAction}
-      </Button>
-    </div>
-  );
-}
-
-/**
- * The in-progress agent reply's bubble: same header (avatar, name, agent
- * badge) a finished agent message would show — `item.sender` is the agent
- * participant `mergeStreamingReply` resolved it against, exactly as
- * `senderDisplay` matches any other message's sender — but no hover
- * toolbar, reactions, pin toggle, or thread affordance, since none of
- * those round-trips make sense against a message the server hasn't
- * persisted (or issued an id for) yet. The blinking `chat-block-cursor`
- * after the text is the one visible cue this bubble is still growing.
- */
-function StreamingMessageGroup({
-  item,
-  participants,
-  currentUser,
-  showDayDivider,
-  agentDisplayNames,
-}: {
-  readonly item: TimelineMessageItem;
-  readonly participants: readonly ParticipantRecord[];
-  readonly currentUser: CurrentUser | undefined;
-  readonly showDayDivider: boolean;
-  readonly agentDisplayNames?: AgentDisplayNames;
-}) {
-  const text = messageText(item);
-  const display = senderDisplay(item.sender, participants, currentUser, agentDisplayNames);
-
-  return (
-    <div className="chat-message-group" id={messageDomId(item.id)}>
-      {showDayDivider && <DayDivider createdAt={item.createdAt} />}
-      <div className="chat-bubble-row" data-own="false">
-        {display !== undefined && (
-          <SenderAvatar
-            id={display.id}
-            initials={display.initials}
-            label={display.label}
-            isAgent={display.isAgent}
-          />
-        )}
-        <div className="chat-bubble">
-          {display !== undefined && (
-            <div className="chat-bubble-head">
-              <span className="chat-bubble-sender">
-                {display.label}
-                {display.isAgent && <AgentBadge />}
-              </span>
-            </div>
-          )}
-          <p className="chat-bubble-text">
-            {text}
-            <span className="chat-block-cursor" aria-hidden="true" />
-          </p>
-        </div>
-      </div>
-    </div>
-  );
-}
-
-/**
- * The ellipsis/right-click menu for a message: reply-in-thread, copy,
- * and Edit (own prompts) in one place so the hover ellipsis and a
- * right-click always offer the same actions.
- */
-function buildMessageMenu({
-  item,
-  threadAffordanceMode,
-  onOpenThread,
-  onEditMessage,
-}: {
-  readonly item: MessageItem;
-  readonly threadAffordanceMode: ThreadAffordanceMode;
-  readonly onOpenThread: ((messageId: string) => void) | undefined;
-  readonly onEditMessage: ((messageId: string) => void) | undefined;
-}): ContextMenu {
-  const entries: ContextMenuEntry[] = [];
-
-  if (onOpenThread !== undefined) {
-    entries.push(
-      contextMenuItem({
-        id: "reply-in-thread",
-        label:
-          threadAffordanceMode === "fork"
-            ? CHAT_STRINGS.forkThreadAction
-            : CHAT_STRINGS.replyInThreadAction,
-        icon: <ArrowBendUpLeft aria-hidden="true" />,
-        onSelect: () => onOpenThread(item.id),
-      }),
-    );
-  }
-
-  if (onEditMessage !== undefined) {
-    entries.push(
-      contextMenuItem({
-        id: "edit-message",
-        label: CHAT_STRINGS.editMessageAction,
-        icon: <PencilSimple aria-hidden="true" />,
-        onSelect: () => onEditMessage(item.id),
-      }),
-    );
-  }
-
-  const text = messageText(item);
-  if (text.length > 0) {
-    entries.push(
-      contextMenuItem({
-        id: "copy-text",
-        label: CHAT_STRINGS.copyTextAction,
-        icon: <Copy aria-hidden="true" />,
-        onSelect: () => {
-          void copyMessageText(text);
-        },
-      }),
-    );
-  }
-
-  return { entries };
-}
-
-/**
- * The compact trailing-edge action cluster a message reveals on hover or
- * keyboard focus-within — add-reaction, reply-in-thread, edit-own-prompt,
- * and the ellipsis menu (see `buildMessageMenu`). Nothing here renders
- * permanently; a quiet conversation shows plain text until a reader hovers
- * a line, matching the reference pattern this replaces (a persistent inline
- * "Reply in thread" link under every message).
- */
-function MessageHoverToolbar({
-  messageId,
-  menu,
-  menuOpen,
-  onOpenMenu,
-  threadAffordanceMode,
-  onOpenThread,
-  onEditMessage,
-}: {
-  readonly messageId: string;
-  readonly menu: ContextMenu;
-  readonly menuOpen: boolean;
-  readonly onOpenMenu: (x: number, y: number, origin: Element) => void;
-  readonly threadAffordanceMode: ThreadAffordanceMode;
-  readonly onOpenThread?: (messageId: string) => void;
-  readonly onEditMessage?: (messageId: string) => void;
-}) {
-  const menuHasEntries = !isContextMenuEmpty(menu);
-  if (onOpenThread === undefined && onEditMessage === undefined && !menuHasEntries) {
-    return null;
-  }
-
-  return (
-    <div
-      className="chat-hover-toolbar"
-      data-thread-affordance-mode={threadAffordanceMode}
-      data-open={menuOpen}
-    >
-      {onOpenThread !== undefined ? (
-        <button
-          type="button"
-          className="chat-hover-reply"
-          aria-label={
-            threadAffordanceMode === "fork"
-              ? CHAT_STRINGS.forkThreadAction
-              : CHAT_STRINGS.replyInThreadAction
-          }
-          onClick={() => onOpenThread(messageId)}
-        >
-          <ArrowBendUpLeft aria-hidden="true" />
-        </button>
-      ) : null}
-      {onEditMessage !== undefined ? (
-        <button
-          type="button"
-          className="chat-hover-edit"
-          aria-label={CHAT_STRINGS.editMessageAction}
-          onClick={() => onEditMessage(messageId)}
-        >
-          <PencilSimple aria-hidden="true" />
-        </button>
-      ) : null}
-      {menuHasEntries ? (
-        <button
-          type="button"
-          className="chat-hover-ellipsis"
-          aria-label={CHAT_STRINGS.messageActionsMenuLabel}
-          aria-expanded={menuOpen}
-          onClick={(event) => {
-            const rect = event.currentTarget.getBoundingClientRect();
-            onOpenMenu(rect.left, rect.bottom, event.currentTarget);
-          }}
-        >
-          <DotsThree aria-hidden="true" />
-        </button>
-      ) : null}
-    </div>
-  );
-}
-
-/**
- * `MessageParts`'s own memo guard: a streamed token, a typing
- * ping, or a presence update re-renders `WorkbenchTimeline`'s parent with a
- * freshly-built `items` array (`mergeStreamingReply`/`mergePendingSends` in
- * `chat-workspace.tsx`), but every *unchanged* message keeps its own
- * object identity across that rebuild — only the growing streaming bubble
- * and the array wrapper are new. Without this guard, every row re-runs its
- * full render (markdown, menu building, avatar lookups) on every token of
- * someone else's reply, which is the dominant cause of "jerky" scrolling
- * during a live turn. Handler props (`onOpenThread` and friends) are
- * excluded on purpose: the host recreates them each render regardless, and
- * they carry no data this component displays, only what it calls back
- * into — so treating them as always-equal costs nothing and is what makes
- * this guard effective at all. `items` (the full timeline, used only to
- * recover retry text for a failed turn — see its own doc below) is
- * excluded the same way; its reference changes every render independent of
- * this row's own content, and a one-render-stale read of it is invisible to
- * the reader.
- */
-function messagePartsPropsEqual(
-  prev: Readonly<Record<string, unknown>>,
-  next: Readonly<Record<string, unknown>>,
-): boolean {
-  const ignoredKeys = new Set(["items"]);
-  const keys = new Set([...Object.keys(prev), ...Object.keys(next)]);
-  for (const key of keys) {
-    if (ignoredKeys.has(key)) continue;
-    const prevValue = prev[key];
-    const nextValue = next[key];
-    if (typeof prevValue === "function" && typeof nextValue === "function") {
-      continue;
-    }
-    if (prevValue !== nextValue) return false;
-  }
-  return true;
-}
-
-function MessagePartsInner({
-  item,
-  items,
-  participants,
-  currentUser,
-  showDayDivider,
-  showHeader,
-  collapsedJoinText,
-  threadMeta,
-  threadAffordanceMode = "reply",
-  onOpenThread,
-  onEditMessage,
-  onOpenProfile,
-  onOpenArtifact,
-  onOpenArtifactInLibrary,
-  onFixConnection,
-  approvalActions,
-  connectServiceActions,
-  pendingActions,
-  failedTurnRecovery,
-  onRetryFailedTurn,
-  onWhatHappenedFailedTurn,
-  agentDisplayNames,
-}: {
-  readonly item: TimelineMessageItem;
-  /** The full timeline, oldest→newest — only read to recover the request
-   * text a failed-turn notice answered (`findRetryText`), never for
-   * anything else this component renders. */
-  readonly items: readonly TimelineMessageItem[];
-  readonly participants: readonly ParticipantRecord[];
-  readonly currentUser: CurrentUser | undefined;
-  readonly showDayDivider: boolean;
-  /** `false` when this message continues an unbroken run from the same
-   * author as the item directly above it — see `isGroupedWithPrevious`. */
-  readonly showHeader: boolean;
-  /** Set only on the first item of a collapsed run of consecutive agent
-   * joins — see `collapseAgentJoinRuns`. */
-  readonly collapsedJoinText?: string;
-  readonly threadMeta?: ThreadAffordanceMeta | undefined;
-  readonly threadAffordanceMode?: ThreadAffordanceMode;
-  readonly onOpenThread?: (messageId: string) => void;
-  readonly onEditMessage?: (messageId: string) => void;
-  readonly onOpenProfile?: (subject: ProfileSubject) => void;
-  readonly onOpenArtifact?: (part: Part & { kind: "file" }) => void;
-  readonly onOpenArtifactInLibrary?: (part: Part & { kind: "file" }) => void;
-  /** The classified-inference-failure text bubble's quiet "Fix this
-   * connection" action — undefined renders no affordance at
-   * all, the same "no port, no feature" contract every other optional
-   * action here follows. No chat-ui component owns routing: the host
-   * decides where "fix" goes (Tools' connect panel today). */
-  readonly onFixConnection?: () => void;
-  readonly approvalActions?: ApprovalActions;
-  /** Host round-trip for the generic "connect-service" card. Undefined
-   * renders every connect-service card in its disconnected framing. */
-  readonly connectServiceActions?: ConnectServiceActions;
-  /** This reader's own failed send's inline Retry/Discard — see
-   * `PendingActions`. Undefined on every ordinary message; on a failed
-   * pending item (`item.pendingStatus === "failed"`) with no actions
-   * wired, the failed row simply doesn't render. */
-  readonly pendingActions?: PendingActions;
-  /** The failed-turn strip's Retry/what-happened actions —
-   * see `WorkbenchTimeline`'s own doc of the same two props. Undefined
-   * renders the strip with inert buttons, never hiding the strip
-   * itself: a failed turn stays visible even on a host that wires no
-   * recovery action for it. */
-  readonly onRetryFailedTurn?: (
-    item: TimelineMessageItem,
-    retryText?: string,
-  ) => void | Promise<void>;
-  readonly onWhatHappenedFailedTurn?: (item: TimelineMessageItem) => void;
-  readonly failedTurnRecovery?: FailedTurnRecovery;
-  /** Resolved agent display names — headers, strips, and event
-   * lines show these, never raw handle slugs. */
-  readonly agentDisplayNames?: AgentDisplayNames;
-}) {
-  // A message this reader's own composer submitted and the server hasn't
-  // issued an id for yet (see `TimelineMessageItem.pendingStatus`) offers
-  // none of the round-trips below — thread, context menu — since every
-  // one of them targets a server-issued message id that doesn't exist
-  // yet for this item. System / error / connect rows
-  // likewise offer none of the social chrome — see
-  // `offersMessageSocialChrome`.
-  const isPending = item.pendingStatus !== undefined;
-  const offersSocialChrome = !isPending && offersMessageSocialChrome(item);
-  // System notices (join / rename / membership) never read as own even when
-  // this viewer triggered them — see `isSystemNoticeItem`.
-  const isOwn =
-    currentUser !== undefined &&
-    item.sender !== undefined &&
-    !isSystemNoticeItem(item) &&
-    !isSystemSenderItem(item) &&
-    localPartOf(item.sender.address) === currentUser.principalId;
-  const ownEdit =
-    isOwn && onEditMessage !== undefined && messageText(item).length > 0
-      ? onEditMessage
-      : undefined;
-  const contextMenu = useContextMenuState();
-  const menu = offersSocialChrome
-    ? buildMessageMenu({
-        item,
-        threadAffordanceMode,
-        onOpenThread,
-        onEditMessage: ownEdit,
-      })
-    : { entries: [] };
-  const replyCount = threadMeta?.replyCount ?? 0;
-  const pendingNonce = item.pendingNonce ?? item.id;
-  // Same identity `WorkbenchTimeline`'s render loop keys this whole group
-  // under (`clientId` when the wire echoed one, else `id`) — reused here
-  // for each part's own key so a pending send's `TextBubble` (and its
-  // avatar) is the very DOM node its later confirmed copy updates in
-  // place, never a remount keyed off the pending nonce vs. the eventual
-  // server-issued id.
-  const groupKey = item.clientId ?? item.id;
-
-  function handleContextMenu(event: ReactMouseEvent<HTMLDivElement>) {
-    if (!offersSocialChrome || isContextMenuEmpty(menu)) return;
-    event.preventDefault();
-    contextMenu.show(event.clientX, event.clientY, menu, event.currentTarget);
-  }
-
-  return (
-    <div
-      className="chat-message-group"
-      id={messageDomId(item.id)}
-      data-grouped={!showHeader}
-      data-own={isOwn}
-      data-pending={item.pendingStatus}
-      onContextMenu={handleContextMenu}
-    >
-      {showDayDivider && <DayDivider createdAt={item.createdAt} />}
-      <div className="chat-message-row">
-        <div className="chat-message-body">
-          {groupTimelineParts(item.parts, groupKey).map((group) => {
-            const key = group.key;
-            if (group.kind === "tool-activity") {
-              return <ToolActivityGroup key={key} rows={group.rows} />;
-            }
-            const part = group.part;
-            if (part.kind === "text" && part.turnFailed === true) {
-              const retryText = findRetryText(items, item);
-              return (
-                <FailedTurnStrip
-                  key={key}
-                  item={item}
-                  detailText={part.text}
-                  participants={participants}
-                  currentUser={currentUser}
-                  {...(part.turnFailedReason === "model_unavailable" ||
-                  part.turnFailedReason === "tools_unsupported"
-                    ? { namedRecovery: part.turnFailedReason }
-                    : {})}
-                  {...(agentDisplayNames !== undefined ? { agentDisplayNames } : {})}
-                  {...(retryText !== undefined ? { retryText } : {})}
-                  {...(failedTurnRecovery !== undefined ? { failedTurnRecovery } : {})}
-                  {...(onRetryFailedTurn !== undefined ? { onRetryFailedTurn } : {})}
-                  {...(onWhatHappenedFailedTurn !== undefined ? { onWhatHappenedFailedTurn } : {})}
-                />
-              );
-            }
-            if (part.kind === "text" && part.turnCancelled === true) {
-              return (
-                <CancelledTurnStrip
-                  key={key}
-                  item={item}
-                  participants={participants}
-                  currentUser={currentUser}
-                  {...(agentDisplayNames !== undefined ? { agentDisplayNames } : {})}
-                />
-              );
-            }
-            if (part.kind === "text") {
-              return (
-                <TextBubble
-                  key={key}
-                  text={part.text}
-                  createdAt={item.createdAt}
-                  sender={item.sender}
-                  participants={participants}
-                  currentUser={currentUser}
-                  showHeader={showHeader}
-                  {...(agentDisplayNames !== undefined ? { agentDisplayNames } : {})}
-                  {...(item.pendingStatus !== undefined
-                    ? { pendingStatus: item.pendingStatus, pendingNonce }
-                    : {})}
-                  {...(pendingActions !== undefined ? { pendingActions } : {})}
-                  {...(onOpenProfile !== undefined ? { onOpenProfile } : {})}
-                  {...(onFixConnection !== undefined ? { onFixConnection } : {})}
-                />
-              );
-            }
-            if (part.kind === "event") {
-              return (
-                <EventLine
-                  key={key}
-                  part={part}
-                  createdAt={item.createdAt}
-                  participants={participants}
-                  {...(collapsedJoinText !== undefined ? { collapsedText: collapsedJoinText } : {})}
-                  {...(agentDisplayNames !== undefined ? { agentDisplayNames } : {})}
-                />
-              );
-            }
-            if (part.kind === "file") {
-              return (
-                <FilePartView
-                  key={key}
-                  part={part}
-                  {...(onOpenArtifact !== undefined ? { onOpenArtifact } : {})}
-                  {...(onOpenArtifactInLibrary !== undefined ? { onOpenArtifactInLibrary } : {})}
-                />
-              );
-            }
-            // The agent's own thinking still renders through react-ui, which
-            // owns the reasoning disclosure. Tool calls no longer do: they
-            // arrive here already folded into rounds by `groupTimelineParts`
-            // above, and react-ui's `ToolBlock` renders one call at a time
-            // with its arguments and result as `JSON.stringify` output.
-            if (part.kind === "reasoning") {
-              return <PartsRenderer key={key} parts={[toReactUiReasoning(part)]} />;
-            }
-            if (part.kind === "block") {
-              return (
-                <BlockPartView
-                  key={key}
-                  block={part.block}
-                  {...(approvalActions !== undefined ? { approvalActions } : {})}
-                  {...(connectServiceActions !== undefined ? { connectServiceActions } : {})}
-                />
-              );
-            }
-            return <FallbackPart key={key} part={part} />;
-          })}
-        </div>
-        {offersSocialChrome && onOpenThread !== undefined && replyCount > 0 ? (
-          <ThreadAffordance
-            messageId={item.id}
-            meta={threadMeta}
-            mode={threadAffordanceMode}
-            participants={participants}
-            onOpen={() => onOpenThread(item.id)}
-            {...(agentDisplayNames !== undefined ? { agentDisplayNames } : {})}
-          />
-        ) : null}
-        {offersSocialChrome ? (
-          <MessageHoverToolbar
-            messageId={item.id}
-            menu={menu}
-            menuOpen={contextMenu.open}
-            onOpenMenu={(x, y, origin) => contextMenu.show(x, y, menu, origin)}
-            threadAffordanceMode={threadAffordanceMode}
-            {...(onOpenThread !== undefined ? { onOpenThread } : {})}
-            {...(ownEdit !== undefined ? { onEditMessage: ownEdit } : {})}
-          />
-        ) : null}
-      </div>
-      <ContextMenuView
-        x={contextMenu.x}
-        y={contextMenu.y}
-        menu={contextMenu.menu}
-        open={contextMenu.open}
-        restoreFocusTo={contextMenu.triggerElement}
-        onOpenChange={(next) => {
-          if (!next) contextMenu.hide();
-        }}
-      />
-    </div>
-  );
-}
-
-const MessageParts = memo(MessagePartsInner, messagePartsPropsEqual);
-
-/**
- * Whether `item`'s header (avatar + name + timestamp) collapses because it
- * continues an unbroken run of text messages from the same author as
- * `previous` — the compact grouped-message pattern modern chat UIs use so a
- * quick back-to-back exchange doesn't repeat the same name and avatar on
- * every line. Never groups across a day divider or a message that isn't
- * itself a plain text bubble (an event line or a fallback block always
- * gets its own header on the next real bubble). A pending (optimistic)
- * send groups exactly like any confirmed message from the same author —
- * Renders it through this same path, not a separate tier.
- */
-function isGroupedWithPrevious(
-  item: TimelineMessageItem,
-  previous: TimelineMessageItem | undefined,
-  showDayDivider: boolean,
-): boolean {
-  if (showDayDivider || previous === undefined) return false;
-  const isTextOnly = (target: TimelineMessageItem) =>
-    target.parts.every((part) => part.kind === "text") &&
-    target.parts.some((part) => part.kind === "text");
-  if (!isTextOnly(item) || !isTextOnly(previous)) return false;
-  const address = item.sender?.address;
-  return address !== undefined && address === previous.sender?.address;
-}
-
-export type ThreadAffordanceMeta = {
-  readonly replyCount: number;
-  readonly lastActivityAt: string | null;
-  readonly participantAddresses: readonly string[];
-};
-
-function ThreadAffordance({
-  messageId,
-  meta,
-  mode,
-  participants,
-  onOpen,
-  agentDisplayNames,
-}: {
-  readonly messageId: string;
-  readonly meta: ThreadAffordanceMeta | undefined;
-  readonly mode: ThreadAffordanceMode;
-  readonly participants: readonly ParticipantRecord[];
-  readonly onOpen: () => void;
-  readonly agentDisplayNames?: AgentDisplayNames;
-}) {
-  const replyCount = meta?.replyCount ?? 0;
-  const addresses = meta?.participantAddresses ?? [];
-  const chips = addresses.slice(0, 3).map((address) => {
-    const isAgent = isAgentAddress(address);
-    const handle =
-      displayNameForAddress(address, agentDisplayNames) ??
-      participants.find((p) => p.address === address)?.handle ??
-      address.slice(0, 1);
-    return {
-      address,
-      isAgent,
-      label: handle,
-      initials: initialsOf(handle),
-    };
-  });
-  const activity = formatRelativeActivity(meta?.lastActivityAt ?? null);
-  const label =
-    replyCount === 0
-      ? mode === "fork"
-        ? CHAT_STRINGS.forkThreadAction
-        : "Reply in thread"
-      : replyCount === 1
-        ? "1 reply"
-        : `${replyCount} replies`;
-
-  return (
-    <div
-      className="chat-thread-affordance"
-      data-message-id={messageId}
-      data-thread-affordance-mode={mode}
-    >
-      {chips.length > 0 ? (
-        <span className="chat-thread-avatar-stack" aria-hidden="true">
-          {chips.map((chip, index) =>
-            chip.isAgent ? (
-              <CorbitAvatar
-                key={`${chip.address}-${index}`}
-                ariaLabel={chip.label}
-                size={20}
-                className="thread-avatar-chip !overflow-hidden !rounded-full !bg-transparent !p-0"
-              />
-            ) : (
-              <span
-                key={`${chip.address}-${index}`}
-                className={`thread-avatar-chip ${avatarClassForPrincipal(chip.address)}`}
-              >
-                {chip.initials}
-              </span>
-            ),
-          )}
-        </span>
-      ) : null}
-      <span className="chat-thread-affordance-meta">
-        <span className="chat-thread-reply-count">{label}</span>
-        {activity !== "" ? <span className="chat-thread-last-activity">{activity}</span> : null}
-      </span>
-      <button type="button" className="chat-thread-open" onClick={onOpen}>
-        {mode === "fork" ? CHAT_STRINGS.forkThreadAction : "Open"}
-      </button>
-    </div>
-  );
-}
-
-/** A workbench's scroll position, captured/restored across a
- * `WorkbenchTimeline` unmount-remount (e.g. opening/closing Settings) — see
- * `WorkbenchTimeline`'s `scrollRestore`/`onScrollSnapshot`. */
-export type ScrollSnapshot = {
-  readonly scrollTop: number;
-  readonly pinned: boolean;
-};
-
-export function WorkbenchTimeline({
-  items,
-  participants = [],
-  settingUpAgent,
-  currentUser,
-  threadMetaByMessageId,
-  threadAffordanceMode = "reply",
-  onOpenThread,
-  onEditMessage,
-  onOpenProfile,
-  onOpenArtifact,
-  onOpenArtifactInLibrary,
-  onFixConnection,
-  approvalActions,
-  connectServiceActions,
-  pendingActions,
-  failedTurnRecovery,
-  onRetryFailedTurn,
-  onWhatHappenedFailedTurn,
-  scrollRestore,
-  onScrollSnapshot,
-  footer,
-  agentDisplayNames,
-}: {
-  /** Server-issued messages, oldest→newest, plus any optimistic entries
-   * the host is still resolving — see `TimelineMessageItem`'s
-   * `pendingStatus`. An ordinary item simply omits it. */
-  readonly items: readonly TimelineMessageItem[];
-  readonly participants?: readonly ParticipantRecord[];
-  /** True for an agent chat still finishing its background launch —
-   * renders the setting-up state instead of "No messages yet". */
-  readonly settingUpAgent?: boolean;
-  readonly currentUser?: CurrentUser;
-  /** ArrowBendUpLeft-thread summary keyed by parent message id. */
-  readonly threadMetaByMessageId?: ReadonlyMap<string, ThreadAffordanceMeta>;
-  /** `"reply"` on the workbench root feed, `"fork"` inside an open thread —
-   * see `ThreadAffordanceMode`. */
-  readonly threadAffordanceMode?: ThreadAffordanceMode;
-  readonly onOpenThread?: (messageId: string) => void;
-  readonly onEditMessage?: (messageId: string) => void;
-  readonly onOpenProfile?: (subject: ProfileSubject) => void;
-  /** Open a message's artifact chip — the host resolves where that goes
-   * (Library today; canvas is a follow-up). No chat-ui component owns
-   * routing, mirroring `onOpenThread` and `onOpenProfile`. */
-  readonly onOpenArtifact?: (part: Part & { kind: "file" }) => void;
-  /** The chip's "Open in Library" affordance — a second, host-supplied hop
-   * alongside `onOpenArtifact`, only ever offered when the part carries an
-   * `artifactId` (see `ArtifactChip`). */
-  readonly onOpenArtifactInLibrary?: (part: Part & { kind: "file" }) => void;
-  /** The classified-inference-failure text bubble's quiet "Fix this
-   * connection" action — see `MessageParts`' own doc. */
-  readonly onFixConnection?: () => void;
-  /** The approve block's live round-trip — the host's read/approve/reject
-   * on the platform approval a card references. Undefined renders every
-   * approve card in its pre-round-trip fixed-disabled framing. */
-  readonly approvalActions?: ApprovalActions;
-  /** Host round-trip for the generic "connect-service" card. Undefined
-   * renders every connect-service card in its disconnected framing. */
-  readonly connectServiceActions?: ConnectServiceActions;
-  /** The failed pending bubble's inline Retry/Discard — see
-   * `PendingActions`. Undefined renders a failed pending item with no
-   * recovery affordance at all (still shown as failed). */
-  readonly pendingActions?: PendingActions;
-  /** Retry action offered on a failed-turn strip — the
-   * server's undelivered-turn notice (`agent_turns` closed `failed`,
-   * see `postUndeliveredNotice`), rendered via `FailedTurnStrip` above.
-   * Undefined still renders the strip, just with a Retry button that
-   * does nothing when pressed — the strip's job is to make the failure
-   * visible, which it does either way. */
-  readonly onRetryFailedTurn?: (
-    item: TimelineMessageItem,
-    retryText?: string,
-  ) => void | Promise<void>;
-  /** The failed-turn strip's "what happened" action — same undefined
-   * contract as `onRetryFailedTurn`. */
-  readonly onWhatHappenedFailedTurn?: (item: TimelineMessageItem) => void;
-  /** Inline model picker + Settings hop for a model-unavailable notice. */
-  readonly failedTurnRecovery?: FailedTurnRecovery;
-  /** The scroll position to restore on mount — the host's own memory of
-   * where this workbench's reader last was, captured via `onScrollSnapshot`
-   * the last time this component unmounted (e.g. opening Settings, which
-   * swaps this whole component out for the settings surface). Undefined
-   * mounts pinned to the bottom, same as a workbench's first-ever render. */
-  readonly scrollRestore?: ScrollSnapshot;
-  /** Called once, from this component's unmount cleanup, with its final
-   * scroll position — the host's only chance to remember it, since this
-   * component owns no state itself once it's gone. */
-  readonly onScrollSnapshot?: (snapshot: ScrollSnapshot) => void;
-  /** Incoming-slot pulse (typing / pending-reply) rendered after the last
-   * message so it sits where the next agent reply will land. */
-  readonly footer?: ReactNode;
-  /** Resolved agent display names — headers, join lines, and
-   * empty states show these, never raw handle slugs. Undefined keeps the
-   * slug-derived fallback, so a host that never resolves names renders
-   * exactly what it always did. */
-  readonly agentDisplayNames?: AgentDisplayNames;
-}) {
-  const containerRef = useRef<HTMLDivElement>(null);
-  // Starts pinned (true) unless a restored snapshot says otherwise — a
-  // workbench's first-ever render always lands at the bottom, but remounting
-  // after Settings closes restores exactly how the reader left it.
-  const [pinnedToLatest, setPinnedToLatest] = useState(scrollRestore?.pinned ?? true);
-  const pinnedRef = useRef(pinnedToLatest);
-
-  // Kept current every render (never a dependency) so the unmount cleanup
-  // below always calls the host's latest callback, not a stale one closed
-  // over at mount time.
-  const onScrollSnapshotRef = useRef(onScrollSnapshot);
-  onScrollSnapshotRef.current = onScrollSnapshot;
-
-  const BOTTOM_PIN_THRESHOLD_PX = 40;
-
-  const handleScroll = () => {
-    const container = containerRef.current;
-    if (container === null) return;
-    const distanceFromBottom =
-      container.scrollHeight - container.scrollTop - container.clientHeight;
-    const nextPinned = distanceFromBottom <= BOTTOM_PIN_THRESHOLD_PX;
-    pinnedRef.current = nextPinned;
-    setPinnedToLatest((current) => (current === nextPinned ? current : nextPinned));
-  };
-
-  const jumpToLatest = () => {
-    const container = containerRef.current;
-    if (container === null) return;
-    pinnedRef.current = true;
-    setPinnedToLatest(true);
-    container.scrollTop = container.scrollHeight;
-  };
-
-  useEffect(() => {
-    const container = containerRef.current;
-    if (container === null) return;
-    if (pinnedRef.current) {
-      container.scrollTop = container.scrollHeight;
-    }
-  }, [items.length, footer != null]);
-
-  // Restores an unpinned reader's exact offset once, on mount — the
-  // items.length effect above already handles the pinned case (it fires on
-  // this same mount). Deliberately empty deps: this only ever runs once, a
-  // restore is a one-time act on remount, not something to repeat every
-  // time `scrollRestore` happens to be a new object.
-  useEffect(() => {
-    const container = containerRef.current;
-    if (container === null) return;
-    if (scrollRestore !== undefined && !scrollRestore.pinned) {
-      container.scrollTop = scrollRestore.scrollTop;
-    }
-    return () => {
-      onScrollSnapshotRef.current?.({
-        scrollTop: container.scrollTop,
-        pinned: pinnedRef.current,
-      });
-    };
-  }, []);
-
-  // A sibling mounting or growing below the timeline (the turn-activity
-  // strip) changes the scroll container's client height without changing
-  // `items.length` — the effect above never fires for it, so a pinned
-  // reader would otherwise watch their own view get visually shoved by
-  // chrome they never asked to track. `ResizeObserver` is absent in some
-  // test environments (jsdom has no implementation), so this is a no-op
-  // there rather than a crash.
-  useEffect(() => {
-    const container = containerRef.current;
-    if (container === null) return;
-    if (typeof ResizeObserver === "undefined") return;
-    const observer = new ResizeObserver(() => {
-      if (!pinnedRef.current) return;
-      container.scrollTop = container.scrollHeight;
-    });
-    observer.observe(container);
-    return () => observer.disconnect();
-  }, []);
-
-  const joinRuns = collapseAgentJoinRuns(items, participants, agentDisplayNames);
-
-  if (items.length === 0) {
-    // A freshly created agent chat answers before it finishes setting up
-    // in the background: the agent participant streams in seconds later.
-    // An empty agent chat is therefore SETTING UP, never "say something" —
-    // that copy invites racing the greeting. Which internal stage that is
-    // never reaches the reader — one honest headline for every wait, with
-    // a rotating tip so the pause feels useful rather than dead.
-    if (settingUpAgent === true) {
-      return (
-        <div className="chat-timeline-empty">
-          <WorkbenchLoadingState delayMs={0} />
-        </div>
-      );
-    }
-    // Once an agent DM's agent has actually joined (see `settingUpAgent`'s
-    // caller), an empty timeline isn't a stage to wait out — it's a ready
-    // conversation with nobody in it yet. Leads with the agent's own name
-    // so the affordance is "message them", not the generic feed copy.
-    const readyAgent = participants.find((participant) => isAgentAddress(participant.address));
-    if (readyAgent !== undefined) {
-      const readyAgentName =
-        displayNameForAddress(readyAgent.address, agentDisplayNames) ??
-        displayNameFromHandle(readyAgent.handle);
-      return (
-        <div className="chat-timeline-empty">
-          <EmptyState
-            icon={<ChatCircle />}
-            title={`Say hello to ${readyAgentName}`}
-            description={CHAT_STRINGS.emptyAgentTimelineDescription}
-          />
-        </div>
-      );
-    }
-    return (
-      <div className="chat-timeline-empty">
-        <EmptyState
-          icon={<ChatCircle />}
-          title={CHAT_STRINGS.emptyTimelineTitle}
-          description={CHAT_STRINGS.emptyTimelineDescription}
-        />
-      </div>
-    );
-  }
-
-  return (
-    <div className="chat-timeline-shell">
-      <div className="chat-timeline" ref={containerRef} onScroll={handleScroll}>
-        {items.map((item, index) => {
-          if (joinRuns.absorbedIds.has(item.id)) return null;
-          const previous = index > 0 ? items[index - 1] : undefined;
-          const showDayDivider =
-            previous === undefined ||
-            !isSameCalendarDay(new Date(previous.createdAt), new Date(item.createdAt));
-          // Keyed by `clientId` (falling back to `id`) when present: a
-          // pending send and the confirmed message that later reconciles
-          // it (wire `clientId`) share this key, so React
-          // updates the same DOM node in place — avatar, header and all —
-          // rather than unmounting a "sending" bubble and mounting an
-          // unrelated "confirmed" one, which would read as an
-          // unsent→sent swap.
-          const key = item.clientId ?? item.id;
-          if (item.streaming === true) {
-            return (
-              <StreamingMessageGroup
-                key={key}
-                item={item}
-                participants={participants}
-                currentUser={currentUser}
-                showDayDivider={showDayDivider}
-                {...(agentDisplayNames !== undefined ? { agentDisplayNames } : {})}
-              />
-            );
-          }
-          const showHeader = !isGroupedWithPrevious(item, previous, showDayDivider);
-          const collapsedJoinText = joinRuns.textByLeadId.get(item.id);
-          return (
-            <MessageParts
-              key={key}
-              item={item}
-              items={items}
-              participants={participants}
-              currentUser={currentUser}
-              showDayDivider={showDayDivider}
-              showHeader={showHeader}
-              {...(agentDisplayNames !== undefined ? { agentDisplayNames } : {})}
-              {...(collapsedJoinText !== undefined ? { collapsedJoinText } : {})}
-              threadMeta={threadMetaByMessageId?.get(item.id)}
-              threadAffordanceMode={threadAffordanceMode}
-              {...(onOpenThread !== undefined ? { onOpenThread } : {})}
-              {...(onEditMessage !== undefined ? { onEditMessage } : {})}
-              {...(onOpenProfile !== undefined ? { onOpenProfile } : {})}
-              {...(onOpenArtifact !== undefined ? { onOpenArtifact } : {})}
-              {...(onFixConnection !== undefined ? { onFixConnection } : {})}
-              {...(onOpenArtifactInLibrary !== undefined ? { onOpenArtifactInLibrary } : {})}
-              {...(approvalActions !== undefined ? { approvalActions } : {})}
-              {...(connectServiceActions !== undefined ? { connectServiceActions } : {})}
-              {...(pendingActions !== undefined ? { pendingActions } : {})}
-              {...(onRetryFailedTurn !== undefined ? { onRetryFailedTurn } : {})}
-              {...(onWhatHappenedFailedTurn !== undefined ? { onWhatHappenedFailedTurn } : {})}
-              {...(failedTurnRecovery !== undefined ? { failedTurnRecovery } : {})}
-            />
-          );
-        })}
-        {footer}
-      </div>
-      {pinnedToLatest ? null : (
-        <button type="button" className="chat-jump-to-latest" onClick={jumpToLatest}>
-          <ArrowDown aria-hidden="true" />
-          {CHAT_STRINGS.jumpToLatestAction}
-        </button>
-      )}
-    </div>
-  );
-}
diff --git a/apps/web/src/chat/typing-indicator.tsx b/apps/web/src/chat/typing-indicator.tsx
deleted file mode 100644
index 660e156f4..000000000
--- a/apps/web/src/chat/typing-indicator.tsx
+++ /dev/null
@@ -1,174 +0,0 @@
-// Presentational typing indicator plus the pure rules that decide whether
-// one is showing, and the stateful hook that drives them off the live
-// stream. The wire event it renders already exists end-to-end —
-// `POST /workbenches/:id/typing` (packages/chat/src/routes.ts) publishes
-// `chat.typing` with `{ principalId }`, and `useWorkbenchStream` already
-// forwards that event type (see use-workbench-stream.ts) — so this is wiring
-// an existing read, not new realtime backend.
-
-import { useEffect, useRef, useState } from "react";
-
-import type { ParticipantRecord } from "./api";
-import { localPartOf, type CurrentUser } from "./timeline";
-import { CHAT_STRINGS } from "./strings";
-
-/** How long a `chat.typing` ping stays reflected in the banner before it's
- * treated as stale — the sender polls its own composer more often than
- * this, so a live typist never visibly flickers. */
-export const TYPING_INDICATOR_TIMEOUT_MS = 4000;
-
-export type TypingEvent = { readonly principalId: string };
-
-/** Parses a `chat.typing` SSE payload at the trust boundary — never trusts
- * the stream's `unknown` data without narrowing it first. */
-export function parseTypingEvent(data: unknown): TypingEvent | null {
-  if (typeof data !== "object" || data === null) return null;
-  const principalId = (data as Record<string, unknown>).principalId;
-  return typeof principalId === "string" ? { principalId } : null;
-}
-
-export type TypingState = {
-  readonly principalId: string;
-  readonly expiresAt: number;
-} | null;
-
-/**
- * The typing banner's whole state machine, pure: a `chat.typing` event
- * (that isn't the signed-in user's own) sets who is typing and when that
- * fact expires; every other event, or an expired banner, clears it. Kept
- * separate from the `setTimeout` that drives it in `useTypingIndicator` so
- * the rule is testable without mounting anything.
- */
-export function nextTypingState(
-  current: TypingState,
-  event: { readonly eventType: string; readonly data: unknown },
-  selfPrincipalId: string | undefined,
-  now: number,
-  timeoutMs: number,
-): TypingState {
-  if (event.eventType !== "chat.typing") return current;
-  const parsed = parseTypingEvent(event.data);
-  if (parsed === null || parsed.principalId === selfPrincipalId) {
-    return current;
-  }
-  return { principalId: parsed.principalId, expiresAt: now + timeoutMs };
-}
-
-/**
- * Whether a banner's `expiresAt` has passed. This is the one place that
- * decides "stale" — `useTypingIndicator`'s `setTimeout` fires at exactly
- * `expiresAt`, but only clears the banner if this still says so, so a timer
- * left over from a since-replaced ping can never clobber a fresher one.
- */
-export function isTypingStateExpired(state: TypingState, now: number): boolean {
-  return state !== null && state.expiresAt <= now;
-}
-
-/** A typing/presence principal's friendly label — prefers the signed-in
- * reader's own `currentUser.name` when the principal is self,
- * else the participant handle, else the same deterministic "Member"
- * fallback the timeline uses. Never a raw address. */
-export function typingLabel(
-  principalId: string,
-  participants: readonly ParticipantRecord[],
-  currentUser?: CurrentUser,
-): string {
-  if (
-    currentUser !== undefined &&
-    currentUser.principalId === principalId &&
-    currentUser.name !== undefined &&
-    currentUser.name.trim().length > 0
-  ) {
-    return currentUser.name.trim();
-  }
-  const match = participants.find(
-    (participant) => localPartOf(participant.address) === principalId,
-  );
-  return match?.handle ?? CHAT_STRINGS.senderFallbackMember;
-}
-
-/**
- * Owns the typing banner's state end to end: feed it every stream event
- * (`chat-workspace.tsx` already sees them all) and it tracks the latest
- * `chat.typing` ping, expiring it on its own timer. `workbenchId` resets the
- * banner immediately on a workbench switch — a ping from the workbench just
- * left means nothing here, and its principal id may not even resolve to
- * the same participant in the new one.
- */
-export function useTypingIndicator(
-  selfPrincipalId: string | undefined,
-  workbenchId: string | null,
-  timeoutMs: number = TYPING_INDICATOR_TIMEOUT_MS,
-): {
-  readonly typingState: TypingState;
-  readonly handleStreamEvent: (eventType: string, data: unknown) => void;
-} {
-  const [typingState, setTypingState] = useState<TypingState>(null);
-  const timerRef = useRef<ReturnType<typeof setTimeout> | undefined>(undefined);
-
-  function clearTimer() {
-    if (timerRef.current !== undefined) {
-      clearTimeout(timerRef.current);
-      timerRef.current = undefined;
-    }
-  }
-
-  // Cleanup runs both on unmount and right before this effect re-fires for
-  // a new workbenchId, so one effect covers the workbench-switch reset and the
-  // unmount guard against a stray setState.
-  useEffect(() => {
-    setTypingState(null);
-    return clearTimer;
-  }, [workbenchId]);
-
-  function handleStreamEvent(eventType: string, data: unknown) {
-    const now = Date.now();
-    const next = nextTypingState(typingState, { eventType, data }, selfPrincipalId, now, timeoutMs);
-    if (next === typingState) return;
-
-    setTypingState(next);
-    clearTimer();
-    if (next !== null) {
-      const expiresAt = next.expiresAt;
-      timerRef.current = setTimeout(() => {
-        setTypingState((current) => (isTypingStateExpired(current, Date.now()) ? null : current));
-      }, expiresAt - now);
-    }
-  }
-
-  return { typingState, handleStreamEvent };
-}
-
-/** Quiet three-dot bubble in the incoming-message slot — same left
- * indent as the next agent reply. Who-is-typing copy is visually hidden
- * so the pulse stays iMessage-subtle without dropping the live-region
- * announcement. */
-function TypingDotsBubble({ status }: { readonly status: string }) {
-  return (
-    <div className="chat-bubble-row chat-typing-row" data-own="false">
-      <div className="chat-typing-indicator" role="status">
-        <span className="chat-typing-indicator-dots" aria-hidden="true">
-          <span />
-          <span />
-          <span />
-        </span>
-        <span className="chat-typing-indicator-label">{status}</span>
-      </div>
-    </div>
-  );
-}
-
-export function TypingIndicator({ label }: { readonly label: string }) {
-  return <TypingDotsBubble status={CHAT_STRINGS.typingIndicator(label)} />;
-}
-
-/**
- * Pulse in the incoming-message slot while in-flight agent streams are open.
- * `names`' order decides who's named before the "and N others" collapse
- * kicks in at three. Renders nothing for an empty list so callers can
- * pass it unconditionally.
- */
-export function AgentTypingIndicator({ names }: { readonly names: readonly string[] }) {
-  if (names.length === 0) return null;
-  return <TypingDotsBubble status={CHAT_STRINGS.agentsTyping(names)} />;
-}
diff --git a/apps/web/src/chat/use-optimistic-sends.ts b/apps/web/src/chat/use-optimistic-sends.ts
deleted file mode 100644
index 2d6e275bf..000000000
--- a/apps/web/src/chat/use-optimistic-sends.ts
+++ /dev/null
@@ -1,356 +0,0 @@
-// This composer's own optimistic sends.
-//
-// A submit shows up in the timeline immediately rather than waiting on the
-// round-trip, and the confirmed message replaces that pending bubble in the
-// very same state update — there is never a render where the message has
-// vanished from both while a fresh read is still in flight, and never one
-// where the pending and confirmed copies both show.
-//
-// The pending bubble's nonce doubles as its wire `clientId`: the server
-// echoes it back and records it, so the next `GET .../messages` page
-// carries it too. `mergePendingSends` drops the pending entry the moment
-// either arrival shows up with a matching `clientId`, so whichever wins
-// that race, the other is a no-op.
-
-import { useEffect, useRef, useState } from "react";
-import { useQueryClient } from "@tanstack/react-query";
-import { ChatApiError, pingWorkbenchPresence, sendInboxMessage } from "./api";
-import type { MessageItem, MessagesResponse } from "./api";
-import { partsForSend } from "./composer";
-import type { ComposerAttachment, ComposerSendPayload } from "./composer";
-import { CHAT_STRINGS } from "./strings";
-import type { PendingMessageStatus, TimelineMessageItem } from "./timeline";
-import { toast } from "@corbits/react-ui";
-import {
-  chatMessagesQueryKey,
-  chatThreadsQueryKey,
-  ensureReplyThreadRow,
-  type ThreadsQueryData,
-} from "./use-workbench-feed";
-
-export type PendingSend = {
-  readonly nonce: string;
-  readonly text: string;
-  readonly attachments: readonly ComposerAttachment[];
-  readonly createdAt: string;
-  readonly status: PendingMessageStatus;
-};
-
-let pendingSendSeq = 0;
-
-/** A fresh client-side nonce for one composer submit — exported so tests
- * can reset the counter between cases without reaching into module
- * internals. */
-export function resetPendingSendNonceForTests(): void {
-  pendingSendSeq = 0;
-}
-
-/** Random per-page-load prefix: a pending nonce doubles as the message's
- * wire `clientId`, which the server persists — a bare counter
- * would repeat `pending_1` on every reload, colliding with a prior
- * session's stored clientId in the same workbench (wrong-message matches
- * in `mergePendingSends`, duplicate React keys in `WorkbenchTimeline`). */
-const pendingSendSession = Math.random().toString(36).slice(2, 10);
-
-function nextPendingSendNonce(): string {
-  pendingSendSeq += 1;
-  return `pending_${pendingSendSession}_${pendingSendSeq}`;
-}
-
-/** The sender address a pending send's synthetic item renders under —
- * `senderDisplay` (`timeline.tsx`) matches its local part against
- * `currentUser.principalId` to render "You" regardless of domain, so the
- * `@pending.local` half is never load-bearing, only honest about the
- * item not being server-issued yet. Shared with `sendPending`'s own
- * synchronous insert (`chat-workspace.tsx`) so a message never changes
- * sender identity mid-flight. */
-export function pendingSenderAddress(currentUserPrincipalId: string | undefined): string {
-  return `${currentUserPrincipalId ?? "you"}@pending.local`;
-}
-
-/**
- * Folds this workspace's own still-in-flight sends onto the end of the
- * server's message list, oldest-first like the rest of the timeline —
- * one message list, rendered through the exact same path as any
- * confirmed message (`WorkbenchTimeline`'s `MessageParts`), never a
- * separate visually-distinct tier. `pendingStatus`/`pendingNonce` are
- * the only markers that distinguish it: a small "sending" clock glyph,
- * or (once failed) an inline retry row — see `TimelineMessageItem`.
- *
- * A pending send's `nonce` doubles as the `clientId` it sent on the wire
- * (see `sendPending`) and is carried onto the synthetic item's own
- * `clientId` too, so it keys identically to whichever confirmed message
- * later reconciles it — `WorkbenchTimeline` renders both under the same
- * React key, updating one DOM node in place rather than unmounting a
- * pending bubble and mounting an unrelated confirmed one.
- *
- * Once `items` contains a confirmed message carrying that same
- * `clientId` (from the POST response landing, or from a later `GET
- * .../messages` page — whichever arrives first), the pending entry is
- * identity-matched and dropped here rather than rendered alongside its
- * own confirmed copy. This is never a heuristic guess from
- * content/timing; a message with no `clientId` at all (sent before this
- * feature, or by a peer) never matches any pending entry.
- */
-export function mergePendingSends(
-  items: readonly MessageItem[],
-  pendingSends: readonly PendingSend[],
-  currentUserPrincipalId: string | undefined,
-): readonly TimelineMessageItem[] {
-  if (pendingSends.length === 0) return items;
-  const confirmedClientIds = new Set(
-    items
-      .map((item) => item.clientId)
-      .filter((clientId): clientId is string => clientId !== undefined),
-  );
-  const unresolvedSends = pendingSends.filter((pending) => !confirmedClientIds.has(pending.nonce));
-  if (unresolvedSends.length === 0) return items;
-  const senderAddress = pendingSenderAddress(currentUserPrincipalId);
-  const pendingItems: TimelineMessageItem[] = unresolvedSends.map((pending) => ({
-    id: pending.nonce,
-    createdAt: pending.createdAt,
-    parts: partsForSend(pending.text, pending.attachments),
-    sender: { name: null, address: senderAddress },
-    clientId: pending.nonce,
-    pendingStatus: pending.status,
-    pendingNonce: pending.nonce,
-  }));
-  return [...items, ...pendingItems];
-}
-
-export interface OptimisticSends {
-  readonly pendingSends: readonly PendingSend[];
-  readonly handleSend: (payload: ComposerSendPayload) => Promise<boolean>;
-  readonly retryPendingSend: (nonce: string) => void;
-  readonly discardPendingSend: (nonce: string) => void;
-}
-
-export function useOptimisticSends(args: {
-  readonly tenantId: string;
-  readonly activeWorkbenchId: string | null;
-  readonly currentUserPrincipalId: string | undefined;
-  readonly openThreadId: string | null;
-  readonly pendingParentMessageId: string | null;
-  readonly openThreadById: (threadId: string) => void;
-  /** Every other participant's mailbox address this send goes `to`
-   * — the room's own `Workbench.participants`, minus the
-   * signed-in sender. */
-  readonly recipientAddresses: readonly string[];
-  /** The loaded feed's own messages, used only to resolve the RFC
-   * `Message-ID` a reply threads onto: `openThreadId`/
-   * `pendingParentMessageId` are mailbox uids (see
-   * `use-thread-navigation.ts`), never the wire id `inReplyTo` needs. */
-  readonly messages: readonly MessageItem[];
-  /** Fires once a send lands in a workbench that has an agent in it: a
-   * reply is owed, so the typing indicator shows now rather than sitting
-   * silent until the turn's first stream event arrives. */
-  readonly noteAwaitingReply: () => void;
-  readonly hasAgentParticipant: boolean;
-  /** Hands recovered text back to the composer's draft — the only door it
-   * comes back through, since a submit always clears the box on the way out. */
-  readonly restoreDraft: (text: string) => void;
-}): OptimisticSends {
-  const {
-    tenantId,
-    activeWorkbenchId,
-    currentUserPrincipalId,
-    openThreadId,
-    pendingParentMessageId,
-    openThreadById,
-    recipientAddresses,
-    messages,
-    noteAwaitingReply,
-    hasAgentParticipant,
-    restoreDraft,
-  } = args;
-  const queryClient = useQueryClient();
-  const [pendingSends, setPendingSends] = useState<readonly PendingSend[]>([]);
-
-  // Switching workbenches drops whatever was pending in the previous one:
-  // that submit targeted that workbench, not wherever the reader went next.
-  useEffect(() => {
-    setPendingSends([]);
-  }, [activeWorkbenchId]);
-
-  // `sendPending` closes over the `activeWorkbenchId` its own render was
-  // called with, which stays fixed for the life of that async call. This
-  // ref tracks the live value so a continuation resolving after the reader
-  // has switched benches can tell its own send is no longer for the
-  // workbench currently on screen.
-  const activeWorkbenchIdRef = useRef(activeWorkbenchId);
-  useEffect(() => {
-    activeWorkbenchIdRef.current = activeWorkbenchId;
-  }, [activeWorkbenchId]);
-
-  async function sendPending(nonce: string, text: string): Promise<void> {
-    if (activeWorkbenchId === null) return;
-    // The mailbox send wire (`{ to, body, inReplyTo? }`) has no room for
-    // an attachment — dropped rather than shimmed; `parts` below
-    // is still text-only, which is exactly what `partsForSend` already
-    // produces for an empty attachments array.
-    const trimmedBody = text.trim();
-    if (trimmedBody.length === 0) return;
-    if (recipientAddresses.length === 0) return;
-    const parts = partsForSend(text, []);
-    // The thread this reply threads onto, by its RFC `Message-ID` — never
-    // `openThreadId`/`pendingParentMessageId` directly, which are mailbox
-    // uids (see `use-thread-navigation.ts`).
-    const replyTargetUid = openThreadId ?? pendingParentMessageId;
-    const inReplyTo =
-      replyTargetUid !== null
-        ? messages.find((item) => item.id === replyTargetUid)?.messageId
-        : undefined;
-    // The pending bubble's own nonce is this send's only identity: the
-    // mailbox route echoes no `clientId`, so `mergePendingSends` matches
-    // this pending entry to its own confirmed write below by uid instead
-    // (see the cache write just under this).
-    try {
-      const sent = await sendInboxMessage(
-        tenantId,
-        recipientAddresses,
-        trimmedBody,
-        inReplyTo !== undefined ? { inReplyTo } : {},
-      );
-      const confirmed: MessageItem = {
-        id: String(sent.uid),
-        createdAt: new Date().toISOString(),
-        parts,
-        sender: {
-          name: null,
-          address: pendingSenderAddress(currentUserPrincipalId),
-        },
-        messageId: sent.messageId,
-        clientId: nonce,
-        // The reply's own thread is the root it threads onto: either the
-        // thread already open, or (starting a fresh one) the message just
-        // replied to — matching `WorkbenchThreadRow.id`'s "root uid as
-        // string" shape (see `mailbox-timeline.ts`).
-        ...(replyTargetUid !== null ? { threadId: replyTargetUid } : {}),
-      };
-      // A refresh already in flight was issued before this send and will
-      // report a mailbox without it — letting it resolve into the cache
-      // would blink the just-sent message back out. Cancelling first is
-      // what makes the write below the last word on this key.
-      await queryClient.cancelQueries({
-        queryKey: chatMessagesQueryKey(tenantId, activeWorkbenchId),
-      });
-      // Written straight into the cache so the confirmed message replaces
-      // the pending bubble in the same render — there is never a frame
-      // where it has vanished from both while a refetch is still in
-      // flight. A refresh may have folded it in already (refresh-first
-      // interleaving); appending unconditionally would render it twice
-      // under one key. When the row is already present but still lacks
-      // `threadId`, patch it in place so a racing stream echo without a
-      // thread cannot leave the confirm stranded on the root feed.
-      queryClient.setQueryData(
-        chatMessagesQueryKey(tenantId, activeWorkbenchId),
-        (current: MessagesResponse | undefined) => {
-          if (current === undefined) return current;
-          const matchIndex = current.items.findIndex(
-            (item) => item.id === confirmed.id || item.clientId === confirmed.clientId,
-          );
-          if (matchIndex >= 0) {
-            const existing = current.items[matchIndex];
-            if (existing === undefined) return current;
-            if (confirmed.threadId !== undefined && existing.threadId !== confirmed.threadId) {
-              const items = current.items.slice();
-              items[matchIndex] = {
-                ...existing,
-                threadId: confirmed.threadId,
-              };
-              return { ...current, items };
-            }
-            return current;
-          }
-          return { ...current, items: [...current.items, confirmed] };
-        },
-      );
-      // Seed / bump the threads cache before navigation opens the just-
-      // created id. Without the row, `useThreadNavigation`'s
-      // stale-id effect would drop `openThreadId` the moment it was set.
-      if (confirmed.threadId !== undefined) {
-        const threadId = confirmed.threadId;
-        const parentMessageId = pendingParentMessageId;
-        queryClient.setQueryData(
-          chatThreadsQueryKey(tenantId, activeWorkbenchId),
-          (current: ThreadsQueryData | undefined) => {
-            if (current === undefined) return current;
-            return ensureReplyThreadRow(current, {
-              threadId,
-              createdAt: confirmed.createdAt,
-              ...(parentMessageId !== null ? { parentMessageId } : {}),
-              bumpReplyCount: true,
-            });
-          },
-        );
-        // A continuation that started before the reader switched to a
-        // different workbench must not drag them back into this one's
-        // thread — `useThreadNavigation` already reset the open thread on
-        // that switch; re-opening it here would undo that reset.
-        if (pendingParentMessageId !== null && activeWorkbenchIdRef.current === activeWorkbenchId) {
-          openThreadById(threadId);
-        }
-      }
-      setPendingSends((current) => current.filter((p) => p.nonce !== nonce));
-      // A message just landed in a workbench with an agent in it: a reply
-      // is owed, so show the typing indicator now rather than sitting
-      // silent until the turn's first stream event arrives.
-      if (hasAgentParticipant) noteAwaitingReply();
-      // No follow-up GET: the confirmed row is already written
-      // above, and this workbench's own `chat.message` echo (dedup'd by
-      // `clientId`/`id` in `applyStreamMessage`) is what every *other*
-      // connection learns the send from. Sending is real activity, so it
-      // doubles as this connection's presence ping.
-      void pingWorkbenchPresence(tenantId, activeWorkbenchId);
-    } catch (cause) {
-      if (cause instanceof ChatApiError && cause.status === 403) {
-        toast(CHAT_STRINGS.mentionForbidden);
-      }
-      setPendingSends((current) =>
-        current.map((p) => (p.nonce === nonce ? { ...p, status: "failed" } : p)),
-      );
-    }
-  }
-
-  async function handleSend(payload: ComposerSendPayload): Promise<boolean> {
-    if (activeWorkbenchId === null) return false;
-    const parts = partsForSend(payload.text, []);
-    if (parts.length === 0) return false;
-    const nonce = nextPendingSendNonce();
-    setPendingSends((current) => [
-      ...current,
-      {
-        nonce,
-        text: payload.text,
-        attachments: payload.attachments,
-        createdAt: new Date().toISOString(),
-        status: "sending",
-      },
-    ]);
-    await sendPending(nonce, payload.text);
-    return true;
-  }
-
-  function retryPendingSend(nonce: string) {
-    const pending = pendingSends.find((p) => p.nonce === nonce);
-    if (pending === undefined) return;
-    setPendingSends((current) =>
-      current.map((p) => (p.nonce === nonce ? { ...p, status: "sending" } : p)),
-    );
-    void sendPending(nonce, pending.text);
-  }
-
-  /** Drops the failed pending bubble and hands its text back to the
-   * composer's draft — the only door recovered text comes back through,
-   * since a submit always clears the box on the way out. */
-  function discardPendingSend(nonce: string) {
-    const pending = pendingSends.find((p) => p.nonce === nonce);
-    if (pending === undefined) return;
-    setPendingSends((current) => current.filter((p) => p.nonce !== nonce));
-    if (pending.text.length > 0) {
-      restoreDraft(pending.text);
-    }
-  }
-
-  return { pendingSends, handleSend, retryPendingSend, discardPendingSend };
-}
diff --git a/apps/web/src/chat/use-thread-navigation.ts b/apps/web/src/chat/use-thread-navigation.ts
deleted file mode 100644
index 14516a824..000000000
--- a/apps/web/src/chat/use-thread-navigation.ts
+++ /dev/null
@@ -1,194 +0,0 @@
-// Which thread the workspace is looking at, and how it gets there.
-//
-// A thread is a place the reader navigates to, but *what it contains* is a
-// filter over the mailbox `use-workbench-feed` already loaded — so this
-// hook owns only the navigation: which thread is open, which message a
-// not-yet-created reply thread would hang off, and the two-level shape the
-// threads menu and breadcrumb both read.
-//
-// Two levels, stop: a depth-1 thread hangs off the root thread; a depth-2
-// sub-thread hangs off a depth-1 thread. The server resolves depth on a
-// fork (redirecting to a sibling when the origin message already sits
-// inside a sub-thread), so nothing here reasons about nesting beyond
-// grouping what it is handed.
-
-import { useCallback, useEffect, useMemo, useRef, useState } from "react";
-import { toast } from "@corbits/react-ui";
-import { forkThread } from "./api";
-import type { WorkbenchThreadRow } from "./api";
-import { CHAT_STRINGS } from "./strings";
-
-export interface ThreadNavigation {
-  /** null = the workbench root feed. */
-  readonly openThreadId: string | null;
-  /** Set when the reader opened a reply on a message that has no thread
-   * yet — the thread is created lazily, by the first send. */
-  readonly pendingParentMessageId: string | null;
-  /** Either of the above: the composer and timeline share one geometry
-   * for "inside a thread", whether or not the thread exists yet. */
-  readonly inThreadView: boolean;
-  readonly openThread: WorkbenchThreadRow | undefined;
-  /** A sub-thread's breadcrumb parent — undefined for a depth-1 thread
-   * (or none open), which breadcrumbs straight back to the workbench. */
-  readonly openThreadParent: WorkbenchThreadRow | undefined;
-  readonly threadTitle: string;
-  readonly depth1Threads: readonly WorkbenchThreadRow[];
-  readonly subThreadsByParentId: ReadonlyMap<string, WorkbenchThreadRow[]>;
-  readonly openThreadForMessage: (messageId: string) => void;
-  readonly forkMessage: (messageId: string) => Promise<void>;
-  readonly openThreadById: (threadId: string) => void;
-  readonly closeThread: () => void;
-}
-
-export function useThreadNavigation(args: {
-  readonly tenantId: string;
-  readonly activeWorkbenchId: string | null;
-  readonly threads: readonly WorkbenchThreadRow[];
-  readonly rootThreadId: string;
-  /** False until `GET /threads` has resolved once — until then an open
-   * thread id cannot be judged stale, only unknown. */
-  readonly threadsLoaded: boolean;
-  readonly refetchThreads: () => Promise<unknown>;
-}): ThreadNavigation {
-  const { tenantId, activeWorkbenchId, threads, rootThreadId, threadsLoaded, refetchThreads } =
-    args;
-  const [openThreadId, setOpenThreadId] = useState<string | null>(null);
-  const [pendingParentMessageId, setPendingParentMessageId] = useState<string | null>(null);
-  // A thread id `openThreadById` just set (first reply create)
-  // can land one render before the seeded `GET /threads` row is visible
-  // to this hook. Hold it so the stale-id effect below does not drop a
-  // brand-new open back to the root feed; clear once the row appears or
-  // the workbench changes.
-  const heldOpenThreadIdRef = useRef<string | null>(null);
-
-  // Switching workbenches resets the view: a thread id belongs to the
-  // workbench it came from.
-  useEffect(() => {
-    heldOpenThreadIdRef.current = null;
-    setOpenThreadId(null);
-    setPendingParentMessageId(null);
-  }, [activeWorkbenchId]);
-
-  // A remembered thread id can outlive the run it named — across a hub
-  // restart the reconnect-ownership challenge treats the run as dead and
-  // every id under it disappears. That is a stale reference, not a
-  // failure: drop it and fall back to the workbench's live feed rather
-  // than leaving the reader staring at an empty thread. A just-created
-  // id still waiting for its seeded row is held, not stale.
-  useEffect(() => {
-    if (openThreadId === null || !threadsLoaded) return;
-    if (threads.some((thread) => thread.id === openThreadId)) {
-      if (heldOpenThreadIdRef.current === openThreadId) {
-        heldOpenThreadIdRef.current = null;
-      }
-      return;
-    }
-    if (heldOpenThreadIdRef.current === openThreadId) return;
-    setOpenThreadId(null);
-  }, [openThreadId, threads, threadsLoaded]);
-
-  const replyThreadFor = useCallback(
-    (messageId: string) =>
-      threads.find((thread) => thread.kind === "reply" && thread.parentMessageId === messageId),
-    [threads],
-  );
-
-  const openThreadForMessage = useCallback(
-    (messageId: string) => {
-      const existing = replyThreadFor(messageId);
-      if (existing !== undefined) {
-        setPendingParentMessageId(null);
-        setOpenThreadId(existing.id);
-        return;
-      }
-      setOpenThreadId(null);
-      setPendingParentMessageId(messageId);
-    },
-    [replyThreadFor],
-  );
-
-  /**
-   * The fork affordance: any message inside an open thread can spawn a
-   * sub-thread rooted at it. Unlike the lazy root-feed reply above, a fork
-   * is created eagerly — the server resolves depth, so this UI never has
-   * to reason about nesting itself.
-   */
-  const forkMessage = useCallback(
-    async (messageId: string) => {
-      if (activeWorkbenchId === null) return;
-      const existing = replyThreadFor(messageId);
-      if (existing !== undefined) {
-        setPendingParentMessageId(null);
-        setOpenThreadId(existing.id);
-        return;
-      }
-      try {
-        const forked = await forkThread(tenantId, activeWorkbenchId, messageId);
-        await refetchThreads();
-        setPendingParentMessageId(null);
-        setOpenThreadId(forked.id);
-      } catch {
-        toast(CHAT_STRINGS.forkThreadError);
-      }
-    },
-    [tenantId, activeWorkbenchId, replyThreadFor, refetchThreads],
-  );
-
-  /** Open a thread that already exists — from the threads menu, a
-   * breadcrumb, or a send that just created one. */
-  const openThreadById = useCallback((threadId: string) => {
-    heldOpenThreadIdRef.current = threadId;
-    setPendingParentMessageId(null);
-    setOpenThreadId(threadId);
-  }, []);
-
-  const closeThread = useCallback(() => {
-    heldOpenThreadIdRef.current = null;
-    setOpenThreadId(null);
-    setPendingParentMessageId(null);
-  }, []);
-
-  const replyThreads = useMemo(
-    () => threads.filter((thread) => thread.kind === "reply"),
-    [threads],
-  );
-  const depth1Threads = useMemo(
-    () => replyThreads.filter((thread) => thread.parentThreadId === rootThreadId),
-    [replyThreads, rootThreadId],
-  );
-  const subThreadsByParentId = useMemo(() => {
-    const map = new Map<string, WorkbenchThreadRow[]>();
-    for (const thread of replyThreads) {
-      if (thread.parentThreadId === null || thread.parentThreadId === rootThreadId) {
-        continue;
-      }
-      const list = map.get(thread.parentThreadId) ?? [];
-      map.set(thread.parentThreadId, [...list, thread]);
-    }
-    return map;
-  }, [replyThreads, rootThreadId]);
-
-  const openThread =
-    openThreadId === null ? undefined : threads.find((thread) => thread.id === openThreadId);
-  const openThreadParent =
-    openThread?.parentThreadId !== undefined &&
-    openThread.parentThreadId !== null &&
-    openThread.parentThreadId !== rootThreadId
-      ? threads.find((thread) => thread.id === openThread.parentThreadId)
-      : undefined;
-
-  return {
-    openThreadId,
-    pendingParentMessageId,
-    inThreadView: openThreadId !== null || pendingParentMessageId !== null,
-    openThread,
-    openThreadParent,
-    threadTitle: openThread?.title ?? (pendingParentMessageId !== null ? "New thread" : "Thread"),
-    depth1Threads,
-    subThreadsByParentId,
-    openThreadForMessage,
-    forkMessage,
-    openThreadById,
-    closeThread,
-  };
-}
diff --git a/apps/web/src/chat/use-workbench-feed.ts b/apps/web/src/chat/use-workbench-feed.ts
deleted file mode 100644
index 4ef87e245..000000000
--- a/apps/web/src/chat/use-workbench-feed.ts
+++ /dev/null
@@ -1,319 +0,0 @@
-// One workbench's feed: the mailbox reads that make it up, every view the
-// timeline can derive from them, and the single refresh that keeps them
-// current.
-//
-// The feed reads through `@corbits/mailbox`'s own thread routes rather than
-// `@corbits/chat`'s message/thread routes now: a workbench is a plain
-// tenant, and every message posted to it already lands in the
-// mailbox via the same fan-out the Inbox reads (see
-// `packages/chat-ui/src/mailbox-timeline.ts`). Thread membership is a
-// property of a message, not a function of which endpoint was called, so
-// the root feed and every open thread are both filters over the one
-// mailbox this hook loads — see `./thread-feed.ts`.
-//
-// Pins and reactions have no mailbox equivalent and are retired with this
-// slice: no chip row, no pin toggle, no pinned strip.
-
-import { useCallback, useEffect, useMemo, useRef } from "react";
-import { useQuery, useQueryClient } from "@tanstack/react-query";
-import {
-  loadRoomMailboxMessages,
-  loadRoomThreadRows,
-  MailboxThreadFetchError,
-  roomMailboxEventsUrl,
-} from "./mailbox-timeline";
-import type { MessageItem, MessagesResponse, WorkbenchThreadRow } from "./api";
-
-/** Whether this workbench's mailbox has loaded, and why not if it hasn't.
- * The items themselves are a separate question — which slice of the
- * mailbox the reader is looking at — so they are not carried here. */
-export type FeedStatus =
-  | { readonly kind: "loading" }
-  | {
-      readonly kind: "error";
-      readonly message: string;
-      /** The workbench itself 404s, not just this load — retrying with the
-       * same id can never succeed, so the UI trades "Try again" for an
-       * honest way out instead. */
-      readonly workbenchNotFound: boolean;
-      /** A 401 means the session itself is gone — "Try again" would hit
-       * the same 401 forever, so the UI offers a way to sign back in
-       * instead of a retry that can never succeed. */
-      readonly isUnauthorized: boolean;
-    }
-  | { readonly kind: "ready" };
-
-/** How long a loaded feed counts as fresh. An agent turn emits dozens of
- * stream events in under a second; with a stale window every one of them
- * after the first is served from cache instead of hitting the hub. */
-const CHAT_FEED_STALE_MS = 1_000;
-
-/** How long stream events are gathered before one refetch goes out. Long
- * enough to swallow a turn's event burst, short enough that a reply still
- * appears immediately. */
-const CHAT_FEED_COALESCE_MS = 250;
-
-/** Stable empty defaults, so a query that hasn't resolved yet doesn't
- * hand the memos below a new array identity on every render. */
-const NO_THREADS: readonly WorkbenchThreadRow[] = [];
-const NO_MESSAGES: readonly MessageItem[] = [];
-
-/** The three reads that make up one workbench's feed. They share a
- * prefix so a single `invalidateQueries` refreshes all of them. */
-export function chatFeedQueryKeyPrefix(tenantId: string, workbenchId: string | null) {
-  return ["chat", "feed", tenantId, workbenchId] as const;
-}
-export function chatMessagesQueryKey(tenantId: string, workbenchId: string | null) {
-  return [...chatFeedQueryKeyPrefix(tenantId, workbenchId), "messages"] as const;
-}
-export function chatThreadsQueryKey(tenantId: string, workbenchId: string | null) {
-  return [...chatFeedQueryKeyPrefix(tenantId, workbenchId), "threads"] as const;
-}
-
-/**
- * The `GET /threads` cache shape — shared by the optimistic-send path that
- * seeds a just-created reply thread before `openThreadById` runs
- *.
- */
-export type ThreadsQueryData = {
-  readonly rootThreadId: string;
-  readonly items: readonly WorkbenchThreadRow[];
-};
-
-/**
- * Ensures a reply-thread row exists for `threadId`, and optionally bumps
- * its activity. A first in-reply-to send uses this to seed the row with
- * `parentMessageId` before navigation opens the thread; a stream echo
- * uses it when the row is still missing so "N replies" and open-by-id
- * have something to hang onto without a refetch.
- *
- * When the row already exists, `parentMessageId` fills in only if the
- * cached row still has `null` (a stream-seeded stub catching up to the
- * sender's known parent) — never overwrites a real parent.
- */
-export function ensureReplyThreadRow(
-  current: ThreadsQueryData,
-  args: {
-    readonly threadId: string;
-    readonly createdAt: string;
-    readonly parentMessageId?: string | null;
-    /** When false, only insert-or-fill — never increment replyCount. */
-    readonly bumpReplyCount?: boolean;
-  },
-): ThreadsQueryData {
-  const bump = args.bumpReplyCount ?? true;
-  const existing = current.items.find((row) => row.id === args.threadId);
-  if (existing !== undefined) {
-    const filledParent =
-      args.parentMessageId !== undefined &&
-      args.parentMessageId !== null &&
-      existing.parentMessageId === null
-        ? args.parentMessageId
-        : existing.parentMessageId;
-    const replyCount = bump ? existing.replyCount + 1 : existing.replyCount;
-    const lastActivityAt = bump ? args.createdAt : existing.lastActivityAt;
-    if (
-      filledParent === existing.parentMessageId &&
-      replyCount === existing.replyCount &&
-      lastActivityAt === existing.lastActivityAt
-    ) {
-      return current;
-    }
-    return {
-      ...current,
-      items: current.items.map((row) =>
-        row.id === args.threadId
-          ? {
-              ...row,
-              parentMessageId: filledParent,
-              replyCount,
-              lastActivityAt,
-            }
-          : row,
-      ),
-    };
-  }
-  const newRow: WorkbenchThreadRow = {
-    id: args.threadId,
-    kind: "reply",
-    parentMessageId: args.parentMessageId ?? null,
-    parentThreadId: current.rootThreadId === "" ? null : current.rootThreadId,
-    runRef: null,
-    title: null,
-    createdAt: args.createdAt,
-    replyCount: bump ? 1 : 0,
-    lastActivityAt: bump ? args.createdAt : null,
-  };
-  return { ...current, items: [...current.items, newRow] };
-}
-
-export interface WorkbenchFeed {
-  readonly threads: readonly WorkbenchThreadRow[];
-  readonly rootThreadId: string;
-  /** Every message in the workbench, unfiltered. What thread a reader is
-   * looking at selects a slice of this — see `./thread-feed.ts`. */
-  readonly loadedMessages: readonly MessageItem[];
-  readonly feedStatus: FeedStatus;
-  readonly threadsLoaded: boolean;
-  readonly refreshFeed: () => void;
-  readonly refetchMessages: () => void;
-  readonly refetchThreads: () => Promise<unknown>;
-}
-
-export function useWorkbenchFeed(args: {
-  readonly tenantId: string;
-  readonly activeWorkbenchId: string | null;
-  readonly onWorkbenchNotFound?: (workbenchId: string) => void;
-}): WorkbenchFeed {
-  const { tenantId, activeWorkbenchId, onWorkbenchNotFound } = args;
-  const queryClient = useQueryClient();
-  // Scoped to the (tenantId, workbenchId) the timer was scheduled for —
-  // not a bare timer handle — so a pending refresh for one workbench can
-  // never make another workbench's `refreshFeed()` call early-return, and
-  // never fires an invalidation against a query key that is no longer the
-  // active one.
-  const refreshTimerRef = useRef<
-    | {
-        readonly tenantId: string;
-        readonly workbenchId: string;
-        readonly timer: ReturnType<typeof setTimeout>;
-      }
-    | undefined
-  >(undefined);
-
-  const messagesQuery = useQuery({
-    queryKey: chatMessagesQueryKey(tenantId, activeWorkbenchId),
-    // Kept as `{ items }` — the same `MessagesResponse` shape the old
-    // `GET .../messages` read produced — so `use-optimistic-sends.ts`'s
-    // own optimistic writes into this cache (which target `.items`,
-    // wholly independent of where the confirmed rows came from) need no
-    // changes for this slice's fetch-source swap.
-    queryFn: async (): Promise<MessagesResponse> => ({
-      items: await loadRoomMailboxMessages(tenantId, activeWorkbenchId ?? ""),
-    }),
-    enabled: activeWorkbenchId !== null,
-    staleTime: CHAT_FEED_STALE_MS,
-  });
-  const threadsQuery = useQuery({
-    queryKey: chatThreadsQueryKey(tenantId, activeWorkbenchId),
-    queryFn: () => loadRoomThreadRows(tenantId, activeWorkbenchId ?? ""),
-    enabled: activeWorkbenchId !== null,
-    staleTime: CHAT_FEED_STALE_MS,
-  });
-
-  const threads = threadsQuery.data?.items ?? NO_THREADS;
-  const rootThreadId = threadsQuery.data?.rootThreadId ?? "";
-  const loadedMessages = messagesQuery.data?.items ?? NO_MESSAGES;
-
-  // A 401 is terminal for this session: keep refetching and the app would
-  // hammer the hub unauthenticated forever, so every refresh trigger
-  // below checks this first. A 404 means the workbench itself is gone
-  // (deleted, or a stale Recents entry that outlived it) — not a
-  // transient failure a retry could fix.
-  const messagesError = messagesQuery.error;
-  const isUnauthorized =
-    messagesError instanceof MailboxThreadFetchError && messagesError.status === 401;
-  const workbenchNotFound =
-    messagesError instanceof MailboxThreadFetchError && messagesError.status === 404;
-
-  // React Query keeps the last successful data through a failed refetch,
-  // so a background failure leaves the timeline exactly as it was and
-  // only a load with nothing to show yet surfaces the error page.
-  const feedStatus: FeedStatus = useMemo(() => {
-    if (activeWorkbenchId === null) return { kind: "loading" };
-    if (messagesQuery.data !== undefined) return { kind: "ready" };
-    if (messagesError !== null) {
-      // Never the raw `MailboxThreadFetchError` message verbatim — like
-      // `describeChatError`, it can embed the request path. `workbenchNotFound`
-      // and `isUnauthorized` below carry the two statuses the UI gives its
-      // own dedicated copy and recovery to; everything else gets this one
-      // plain-language fallback.
-      return {
-        kind: "error",
-        message: "Couldn't load messages.",
-        workbenchNotFound,
-        isUnauthorized,
-      };
-    }
-    return { kind: "loading" };
-  }, [activeWorkbenchId, messagesQuery.data, messagesError, workbenchNotFound, isUnauthorized]);
-
-  useEffect(() => {
-    if (workbenchNotFound && activeWorkbenchId !== null) {
-      onWorkbenchNotFound?.(activeWorkbenchId);
-    }
-  }, [workbenchNotFound, activeWorkbenchId, onWorkbenchNotFound]);
-
-  /** Every read of this workbench's feed, refetched as one. Concurrent
-   * invalidations of a key collapse into a single request, which is what
-   * makes an agent turn's burst of stream events cost one refresh rather
-   * than one per event. */
-  const refreshFeed = useCallback(() => {
-    if (activeWorkbenchId === null || isUnauthorized) return;
-    // Trailing-edge, because `invalidateQueries` refetches whether or not
-    // the data is stale: React Query dedupes requests already in flight,
-    // but an agent turn emits stream events faster than a round-trip
-    // completes, so invalidating on each one still walks the hub once per
-    // gap between responses. Collapsing the burst into one refetch per
-    // window is the difference between ~40 requests per turn and ~2.
-    const pending = refreshTimerRef.current;
-    if (pending !== undefined) {
-      if (pending.tenantId === tenantId && pending.workbenchId === activeWorkbenchId) {
-        return;
-      }
-      // A timer scheduled for a workbench the reader has since left —
-      // clear it rather than let it invalidate that now-inactive query key.
-      clearTimeout(pending.timer);
-    }
-    const workbenchId = activeWorkbenchId;
-    refreshTimerRef.current = {
-      tenantId,
-      workbenchId,
-      timer: setTimeout(() => {
-        refreshTimerRef.current = undefined;
-        void queryClient.invalidateQueries({
-          queryKey: chatFeedQueryKeyPrefix(tenantId, workbenchId),
-        });
-      }, CHAT_FEED_COALESCE_MS),
-    };
-  }, [queryClient, tenantId, activeWorkbenchId, isUnauthorized]);
-
-  useEffect(
-    () => () => {
-      if (refreshTimerRef.current !== undefined) {
-        clearTimeout(refreshTimerRef.current.timer);
-        refreshTimerRef.current = undefined;
-      }
-    },
-    [tenantId, activeWorkbenchId],
-  );
-
-  // Live updates: the mailbox's own SSE stream (the same one Inbox reads)
-  // rather than a bespoke chat one — an event names the affected mail
-  // message's id and (optionally) what happened to it, never the full
-  // row, so the only thing a subscriber can safely do with it is refresh
-  // the feed it might belong to. Coalesced through the same `refreshFeed`
-  // every other trigger uses, so a burst of mail events costs one refetch.
-  useEffect(() => {
-    if (activeWorkbenchId === null) return;
-    // A host with no `EventSource` at all (an older test harness that
-    // never stubs one, matching `useWorkbenchStream`'s own contract) gets
-    // no live updates rather than a thrown error — `refreshFeed` still
-    // runs from every other trigger (send, thread navigation, tab focus).
-    if (typeof EventSource === "undefined") return;
-    const source = new EventSource(roomMailboxEventsUrl(tenantId));
-    source.addEventListener("mailbox", () => refreshFeed());
-    return () => source.close();
-  }, [tenantId, activeWorkbenchId, refreshFeed]);
-
-  return {
-    threads,
-    rootThreadId,
-    loadedMessages,
-    feedStatus,
-    threadsLoaded: threadsQuery.data !== undefined,
-    refreshFeed,
-    refetchMessages: () => void messagesQuery.refetch(),
-    refetchThreads: () => threadsQuery.refetch(),
-  };
-}
diff --git a/apps/web/src/chat/use-workbench-stream.test.tsx b/apps/web/src/chat/use-workbench-stream.test.tsx
deleted file mode 100644
index c35bf4cc9..000000000
--- a/apps/web/src/chat/use-workbench-stream.test.tsx
+++ /dev/null
@@ -1,245 +0,0 @@
-// Real-timer wiring for `useWorkbenchStream`, mounted against a DOM (see
-// dom-environment.ts) with a controllable `EventSource` stand-in so the hook's
-// actual reconnect/poll effects run rather than being reasoned about in the
-// abstract. `backoffDelayMs` itself is covered as a pure function in
-// test/refresh-and-send.test.ts; this suite proves the wiring around it:
-// the stream stays down without ever forcing the caller to render that
-// fact, keeps the timeline advancing via polling the whole time, and
-// reconnects eagerly on tab refocus / network return.
-
-import { afterEach, describe, expect, test } from "bun:test";
-import { act, createElement } from "react";
-import { createRoot } from "react-dom/client";
-
-import { parseStreamEventJson, useWorkbenchStream } from "./use-workbench-stream";
-
-const realEventSource = globalThis.EventSource;
-const sleep = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));
-
-class StubEventSource {
-  static readonly CONNECTING = 0;
-  static readonly OPEN = 1;
-  static readonly CLOSED = 2;
-  static instances: StubEventSource[] = [];
-
-  onopen: (() => void) | null = null;
-  onerror: (() => void) | null = null;
-  readyState = StubEventSource.CONNECTING;
-  listeners = new Map<string, (message: MessageEvent) => void>();
-
-  constructor(readonly url: string) {
-    StubEventSource.instances.push(this);
-  }
-
-  addEventListener(eventType: string, listener: (message: MessageEvent) => void) {
-    this.listeners.set(eventType, listener);
-  }
-
-  emit(eventType: string, data: unknown) {
-    this.listeners.get(eventType)?.({
-      data: JSON.stringify(data),
-    } as MessageEvent);
-  }
-
-  emitRaw(eventType: string, data: string) {
-    this.listeners.get(eventType)?.({ data } as MessageEvent);
-  }
-
-  close() {
-    this.readyState = StubEventSource.CLOSED;
-  }
-
-  open() {
-    this.readyState = StubEventSource.OPEN;
-    this.onopen?.();
-  }
-
-  fail() {
-    this.readyState = StubEventSource.CLOSED;
-    this.onerror?.();
-  }
-}
-
-afterEach(() => {
-  globalThis.EventSource = realEventSource;
-  StubEventSource.instances = [];
-});
-
-function mount(
-  intervals: {
-    pollMs: number;
-    baseDelayMs: number;
-    maxDelayMs: number;
-  },
-  onParseError?: (eventType: string) => void,
-) {
-  globalThis.EventSource = StubEventSource as unknown as typeof EventSource;
-  const container = document.createElement("div");
-  document.body.appendChild(container);
-  const root = createRoot(container);
-  const events: [string, unknown][] = [];
-  let pollCount = 0;
-
-  function Host() {
-    useWorkbenchStream(
-      "/api/tenants/tnt_1/chat/workbenches/c1/stream",
-      (eventType, data) => events.push([eventType, data]),
-      () => {
-        pollCount += 1;
-      },
-      intervals,
-      onParseError,
-    );
-    return null;
-  }
-
-  act(() => {
-    root.render(createElement(Host));
-  });
-
-  return {
-    latest: (): StubEventSource => {
-      const instance = StubEventSource.instances[StubEventSource.instances.length - 1];
-      if (instance === undefined) throw new Error("no EventSource was opened");
-      return instance;
-    },
-    pollCount: () => pollCount,
-    events: () => events,
-    settle: (ms: number) => act(() => sleep(ms)),
-    unmount: () => act(() => root.unmount()),
-  };
-}
-
-describe("useWorkbenchStream (reconnect + poll wiring)", () => {
-  test("a dropped connection keeps the timeline advancing via polling until it reopens", async () => {
-    const harness = mount({ pollMs: 20, baseDelayMs: 500, maxDelayMs: 500 });
-    harness.latest().fail();
-    // startPolling fires an immediate poll, then again every pollMs.
-    expect(harness.pollCount()).toBe(1);
-
-    await harness.settle(50);
-    expect(harness.pollCount()).toBeGreaterThanOrEqual(2);
-
-    const pollingSnapshot = harness.pollCount();
-    harness.latest().open();
-    // Reopen triggers exactly one more silent refresh...
-    expect(harness.pollCount()).toBe(pollingSnapshot + 1);
-
-    // ...and polling stops: waiting past pollMs again shows no further calls.
-    await harness.settle(50);
-    expect(harness.pollCount()).toBe(pollingSnapshot + 1);
-    harness.unmount();
-  });
-
-  test("a tab refocus forces an immediate reconnect attempt instead of waiting out the backoff", async () => {
-    const harness = mount({
-      pollMs: 1000,
-      baseDelayMs: 5000,
-      maxDelayMs: 5000,
-    });
-    harness.latest().fail();
-    const failedCount = StubEventSource.instances.length;
-
-    Object.defineProperty(document, "visibilityState", {
-      configurable: true,
-      get: () => "visible",
-    });
-    document.dispatchEvent(new Event("visibilitychange"));
-
-    expect(StubEventSource.instances.length).toBe(failedCount + 1);
-    harness.unmount();
-  });
-
-  test("the network coming back forces an immediate reconnect attempt", async () => {
-    const harness = mount({
-      pollMs: 1000,
-      baseDelayMs: 5000,
-      maxDelayMs: 5000,
-    });
-    harness.latest().fail();
-    const failedCount = StubEventSource.instances.length;
-
-    window.dispatchEvent(new Event("online"));
-
-    expect(StubEventSource.instances.length).toBe(failedCount + 1);
-    harness.unmount();
-  });
-
-  test("a reconnect kick while already live is a no-op — it never interrupts a healthy stream", async () => {
-    const harness = mount({
-      pollMs: 1000,
-      baseDelayMs: 5000,
-      maxDelayMs: 5000,
-    });
-    harness.latest().open();
-    const liveCount = StubEventSource.instances.length;
-
-    window.dispatchEvent(new Event("online"));
-
-    expect(StubEventSource.instances.length).toBe(liveCount);
-    harness.unmount();
-  });
-
-  test("invalid JSON on chat.message is not forwarded and polls immediately", async () => {
-    const parseErrors: string[] = [];
-    const harness = mount(
-      {
-        pollMs: 1000,
-        baseDelayMs: 5000,
-        maxDelayMs: 5000,
-      },
-      (eventType) => parseErrors.push(eventType),
-    );
-    harness.latest().open();
-    const pollsAfterOpen = harness.pollCount();
-
-    harness.latest().emitRaw("chat.message", "not-json{");
-
-    expect(harness.events()).toEqual([]);
-    expect(harness.pollCount()).toBe(pollsAfterOpen + 1);
-    expect(parseErrors).toEqual(["chat.message"]);
-    harness.unmount();
-  });
-
-  test("valid JSON on chat.message still forwards and does not poll", async () => {
-    const harness = mount({
-      pollMs: 1000,
-      baseDelayMs: 5000,
-      maxDelayMs: 5000,
-    });
-    harness.latest().open();
-    const pollsAfterOpen = harness.pollCount();
-
-    harness.latest().emit("chat.message", { id: "m1", parts: [] });
-
-    expect(harness.events()).toEqual([["chat.message", { id: "m1", parts: [] }]]);
-    expect(harness.pollCount()).toBe(pollsAfterOpen);
-    harness.unmount();
-  });
-});
-
-describe("parseStreamEventJson", () => {
-  test("parses a JSON object through arktype", () => {
-    expect(parseStreamEventJson('{"id":"m1"}')).toEqual({
-      ok: true,
-      data: { id: "m1" },
-    });
-  });
-
-  test("undefined payload is a successful empty event", () => {
-    expect(parseStreamEventJson(undefined)).toEqual({
-      ok: true,
-      data: undefined,
-    });
-  });
-
-  test("invalid JSON is a parse miss, not a thrown error", () => {
-    expect(parseStreamEventJson("not-json{")).toEqual({ ok: false });
-  });
-
-  test("a non-string payload is a parse miss", () => {
-    expect(parseStreamEventJson({ id: "already-parsed" })).toEqual({
-      ok: false,
-    });
-  });
-});
diff --git a/apps/web/src/chat/use-workbench-stream.ts b/apps/web/src/chat/use-workbench-stream.ts
deleted file mode 100644
index 663a6f4cd..000000000
--- a/apps/web/src/chat/use-workbench-stream.ts
+++ /dev/null
@@ -1,199 +0,0 @@
-// Live updates for a workbench: subscribe over SSE, reconnecting with
-// exponential backoff + jitter on drop, polling `onPoll` on an interval the
-// whole time the stream is down so the timeline keeps advancing, and
-// forcing an immediate reconnect attempt when the tab refocuses or the
-// network comes back. `onEvent` fires for every SSE message the platform's
-// stream emits (chat.settings, chat.typing, and the platform's own run
-// events); the caller decides what to do with each — this hook only owns
-// the transport, and connection state is never something the caller should
-// render as chrome. JSON at this boundary is parsed with arktype
-// (`string.json.parse`); a miss is never forwarded as a raw string.
-
-import { type } from "arktype";
-import { useEffect, useRef, useState } from "react";
-
-export type WorkbenchStreamState = "connecting" | "live" | "polling";
-
-const StreamEventJson = type("string.json.parse");
-
-/**
- * The EventSource payload is a JSON string (or absent). Parse it at this
- * boundary so a SyntaxError never becomes a silently dropped `chat.message`.
- */
-export function parseStreamEventJson(
-  raw: unknown,
-): { readonly ok: true; readonly data: unknown } | { readonly ok: false } {
-  if (raw === undefined) return { ok: true, data: undefined };
-  if (typeof raw !== "string") return { ok: false };
-  const parsed = StreamEventJson(raw);
-  if (parsed instanceof type.errors) return { ok: false };
-  return { ok: true, data: parsed };
-}
-
-/**
- * The S3 fix, isolated as a pure rule: with no active workbench there is
- * nothing to stream, so the hook must not open an `EventSource` or start a
- * poll timer at all — an empty url is the caller's signal for that.
- */
-export function shouldConnect(url: string): boolean {
-  return url !== "";
-}
-
-const BASE_DELAY_MS = 500;
-const MAX_DELAY_MS = 8000;
-const POLL_INTERVAL_MS = 5000;
-
-/**
- * Exponential backoff capped at `maxDelayMs`, with up to 30% jitter layered
- * on top so a bench of clients that all dropped together don't all retry in
- * lockstep. `random` is injectable so the schedule is testable without
- * flakiness.
- */
-export function backoffDelayMs(
-  attempt: number,
-  random: () => number = Math.random,
-  baseDelayMs = BASE_DELAY_MS,
-  maxDelayMs = MAX_DELAY_MS,
-): number {
-  const exponential = baseDelayMs * 2 ** Math.max(0, attempt - 1);
-  const withJitter = exponential + exponential * 0.3 * random();
-  return Math.round(Math.min(maxDelayMs, withJitter));
-}
-
-export interface WorkbenchStreamIntervals {
-  readonly pollMs?: number;
-  readonly baseDelayMs?: number;
-  readonly maxDelayMs?: number;
-}
-
-export function useWorkbenchStream(
-  url: string,
-  onEvent: (eventType: string, data: unknown) => void,
-  onPoll: () => void,
-  intervals?: WorkbenchStreamIntervals,
-  onParseError?: (eventType: string) => void,
-): WorkbenchStreamState {
-  const [state, setState] = useState<WorkbenchStreamState>("connecting");
-  const onEventRef = useRef(onEvent);
-  onEventRef.current = onEvent;
-  const onPollRef = useRef(onPoll);
-  onPollRef.current = onPoll;
-  const onParseErrorRef = useRef(onParseError);
-  onParseErrorRef.current = onParseError;
-  const pollMs = intervals?.pollMs ?? POLL_INTERVAL_MS;
-  const baseDelayMs = intervals?.baseDelayMs ?? BASE_DELAY_MS;
-  const maxDelayMs = intervals?.maxDelayMs ?? MAX_DELAY_MS;
-
-  useEffect(() => {
-    if (!shouldConnect(url)) return;
-
-    let cancelled = false;
-    let attempts = 0;
-    let source: EventSource | undefined;
-    let reconnectTimer: ReturnType<typeof setTimeout> | undefined;
-    let pollTimer: ReturnType<typeof setInterval> | undefined;
-
-    const stopPolling = () => {
-      if (pollTimer === undefined) return;
-      clearInterval(pollTimer);
-      pollTimer = undefined;
-    };
-
-    const startPolling = () => {
-      if (cancelled || pollTimer !== undefined) return;
-      setState("polling");
-      onPollRef.current();
-      pollTimer = setInterval(() => onPollRef.current(), pollMs);
-    };
-
-    const connect = () => {
-      if (cancelled) return;
-      if (reconnectTimer !== undefined) {
-        clearTimeout(reconnectTimer);
-        reconnectTimer = undefined;
-      }
-      source?.close();
-      setState((current) => (current === "polling" ? current : "connecting"));
-      source = new EventSource(url);
-
-      source.onopen = () => {
-        if (cancelled) return;
-        attempts = 0;
-        stopPolling();
-        setState("live");
-        // One silent refresh on reopen to catch anything missed while down.
-        onPollRef.current();
-      };
-
-      source.onerror = () => {
-        source?.close();
-        if (cancelled) return;
-        startPolling();
-        attempts += 1;
-        const delay = backoffDelayMs(attempts, Math.random, baseDelayMs, maxDelayMs);
-        reconnectTimer = setTimeout(connect, delay);
-      };
-
-      const forward = (eventType: string) => (message: MessageEvent) => {
-        if (cancelled) return;
-        const parsed = parseStreamEventJson(message.data);
-        if (!parsed.ok) {
-          onParseErrorRef.current?.(eventType);
-          if (eventType === "chat.message") {
-            onPollRef.current();
-          }
-          return;
-        }
-        onEventRef.current(eventType, parsed.data);
-      };
-
-      // "chat.message" is every message posted into the room;
-      // "chat.agent" carries the agent-run events (inference progress,
-      // turn lifecycle) that sit between them. "chat.presence"/
-      // "chat.presence.snapshot" are the who's-here roster, piggybacked
-      // on this same connection rather than a second stream.
-      // "chat.workbenches-mutated" tells the host sidebar the tenant's
-      // workbench list changed (a specialist minted while this stream is
-      // open) — still this workbench's SSE, not a tenant-wide stream.
-      for (const eventType of [
-        "chat.message",
-        "chat.agent",
-        "chat.settings",
-        "chat.typing",
-        "chat.presence",
-        "chat.presence.snapshot",
-        "chat.workbenches-mutated",
-        "message",
-      ]) {
-        source.addEventListener(eventType, forward(eventType));
-      }
-    };
-
-    // A reconnect kick from the browser noticing the tab refocused or the
-    // network came back — skip it if the stream is already open so it
-    // never interrupts a healthy connection.
-    const reconnectNow = () => {
-      if (cancelled || source?.readyState === EventSource.OPEN) return;
-      connect();
-    };
-    const onVisibility = () => {
-      if (document.visibilityState === "visible") reconnectNow();
-    };
-
-    document.addEventListener("visibilitychange", onVisibility);
-    window.addEventListener("online", reconnectNow);
-
-    connect();
-
-    return () => {
-      cancelled = true;
-      document.removeEventListener("visibilitychange", onVisibility);
-      window.removeEventListener("online", reconnectNow);
-      source?.close();
-      if (reconnectTimer !== undefined) clearTimeout(reconnectTimer);
-      stopPolling();
-    };
-  }, [url, pollMs, baseDelayMs, maxDelayMs]);
-
-  return state;
-}
diff --git a/apps/web/src/chat/wire/blocks.test.tsx b/apps/web/src/chat/wire/blocks.test.tsx
deleted file mode 100644
index acc9f6789..000000000
--- a/apps/web/src/chat/wire/blocks.test.tsx
+++ /dev/null
@@ -1,128 +0,0 @@
-// Static-markup rendering of block parts through the timeline: every known
-// block type routes through the registry to its read-only card, and unknown
-// or malformed blocks land on the labeled fallback — never raw JSON.
-
-import { describe, expect, test } from "bun:test";
-import { renderToStaticMarkup } from "react-dom/server";
-
-import type { MessageItem } from "../api";
-import { WorkbenchTimeline } from "../timeline";
-
-function messageWithBlock(type: string, data: unknown): MessageItem[] {
-  return [
-    {
-      id: "m1",
-      createdAt: "2026-01-01T00:00:00.000Z",
-      parts: [{ kind: "block", block: { type, data } }],
-      sender: { name: "Researcher", address: "researcher@agents.example" },
-    },
-  ];
-}
-
-describe("block rendering", () => {
-  test("approve block renders framing with fixed disabled Approve/Not now", () => {
-    const markup = renderToStaticMarkup(
-      <WorkbenchTimeline
-        items={messageWithBlock("approve", {
-          approvalId: "apv_fixture1",
-          title: "Deploy staging",
-          body: "Rolls out the ingest worker.",
-        })}
-      />,
-    );
-    expect(markup).toContain("Deploy staging");
-    expect(markup).toContain("Rolls out the ingest worker.");
-    expect(markup).toContain("Approve");
-    expect(markup).toContain("Not now");
-    expect(markup).toContain("disabled");
-    expect(markup).not.toContain("apv_fixture1");
-  });
-
-  test("steps block renders each step with its state", () => {
-    const markup = renderToStaticMarkup(
-      <WorkbenchTimeline
-        items={messageWithBlock("steps", {
-          title: "Migration",
-          steps: [
-            { label: "Snapshot", state: "done", note: "2s" },
-            { label: "Apply", state: "running" },
-            { label: "Verify", state: "queued" },
-          ],
-        })}
-      />,
-    );
-    expect(markup).toContain("Migration");
-    expect(markup).toContain("Snapshot");
-    expect(markup).toContain('data-state="done"');
-    expect(markup).toContain('data-state="running"');
-    expect(markup).toContain('data-state="queued"');
-    expect(markup).toContain("2s");
-  });
-
-  test("metrics block renders tiles and proportional bars", () => {
-    const markup = renderToStaticMarkup(
-      <WorkbenchTimeline
-        items={messageWithBlock("metrics", {
-          title: "Ingest health",
-          metrics: [
-            { label: "P95", value: "412ms", detail: "-8%", trend: "up" },
-            { label: "Retries", value: "12", detail: "flat" },
-          ],
-          bars: [{ label: "us-east", percent: 64 }],
-        })}
-      />,
-    );
-    expect(markup).toContain("Ingest health");
-    expect(markup).toContain("P95");
-    expect(markup).toContain("412ms");
-    expect(markup).toContain("-8%");
-    expect(markup).toContain('data-trend="up"');
-    expect(markup).not.toContain('data-trend="down"');
-    expect(markup).toContain("us-east");
-    expect(markup).toContain("width:64%");
-    expect(markup).toContain("64%");
-  });
-
-  test("stream block shows a cursor while streaming and none when done", () => {
-    const streaming = renderToStaticMarkup(
-      <WorkbenchTimeline
-        items={messageWithBlock("stream", {
-          title: "Build log",
-          text: "compiling modules",
-          done: false,
-        })}
-      />,
-    );
-    expect(streaming).toContain("compiling modules");
-    expect(streaming).toContain("chat-block-cursor");
-
-    const done = renderToStaticMarkup(
-      <WorkbenchTimeline
-        items={messageWithBlock("stream", {
-          title: "Build log",
-          text: "build complete",
-          done: true,
-        })}
-      />,
-    );
-    expect(done).toContain("build complete");
-    expect(done).not.toContain("chat-block-cursor");
-  });
-
-  test("unknown block type renders the labeled fallback, not raw JSON", () => {
-    const markup = renderToStaticMarkup(
-      <WorkbenchTimeline items={messageWithBlock("carousel", { secret: "payload" })} />,
-    );
-    expect(markup).toContain("Unsupported block");
-    expect(markup).toContain("carousel");
-    expect(markup).not.toContain("payload");
-  });
-
-  test("malformed data for a known type renders the fallback", () => {
-    const markup = renderToStaticMarkup(
-      <WorkbenchTimeline items={messageWithBlock("metrics", { title: 42, metrics: "nope" })} />,
-    );
-    expect(markup).toContain("Unsupported block");
-    expect(markup).not.toContain("nope");
-  });
-});
diff --git a/apps/web/src/chat/workbench-display-title.test.ts b/apps/web/src/chat/workbench-display-title.test.ts
deleted file mode 100644
index 87cc4f7bc..000000000
--- a/apps/web/src/chat/workbench-display-title.test.ts
+++ /dev/null
@@ -1,29 +0,0 @@
-import { describe, expect, test } from "bun:test";
-
-import { CHAT_STRINGS } from "./strings";
-import { displayWorkbenchTitle } from "./workbench-display-title";
-
-describe("displayWorkbenchTitle", () => {
-  test("a title equal to the workbench's own id reads as New workbench", () => {
-    const id = "run_1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d";
-    expect(displayWorkbenchTitle(id, id)).toBe(CHAT_STRINGS.newWorkbenchTitle);
-  });
-
-  test("a title matching the run-id shape reads as New workbench even for a different id", () => {
-    const runId = "run_1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d";
-    expect(displayWorkbenchTitle(runId, "some-other-id")).toBe(CHAT_STRINGS.newWorkbenchTitle);
-  });
-
-  test("a legacy instance-id-shaped title reads as New workbench", () => {
-    const insId = "ins_1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d";
-    expect(displayWorkbenchTitle(insId, "some-other-id")).toBe(CHAT_STRINGS.newWorkbenchTitle);
-  });
-
-  test("a real title renders unchanged", () => {
-    expect(displayWorkbenchTitle("Myra", "run_abc")).toBe("Myra");
-  });
-
-  test("an empty title passes through unchanged for callers to apply their own fallback", () => {
-    expect(displayWorkbenchTitle("", "run_abc")).toBe("");
-  });
-});
diff --git a/apps/web/src/chat/workbench-display-title.ts b/apps/web/src/chat/workbench-display-title.ts
deleted file mode 100644
index 0eb9dbf10..000000000
--- a/apps/web/src/chat/workbench-display-title.ts
+++ /dev/null
@@ -1,21 +0,0 @@
-import { CHAT_STRINGS } from "./strings";
-
-/**
- * `POST /workbenches` titles an untitled mint with its own generated id
- * (`generateId("workflowRun")` -> `run_<32 hex>`; older workbenches carry
- * `generateId("instance")` -> `ins_<32 hex>`) rather than leaving the title
- * empty — see `packages/chat/src/routes.ts`'s `name: chatTitle ?? workbenchId`.
- * That wire id must never reach the UI, so every place a workbench title
- * renders routes through this one check instead of re-deriving it.
- */
-const RUN_ID_SHAPE = /^(?:run|ins)_[0-9a-f]{32}$/;
-
-/**
- * Renders `title` for display, replacing it with "New workbench" when it is
- * the row's own id or otherwise shaped like a generated run/instance id.
- * Leaves any other title — including an empty one — untouched, so callers
- * keep applying their own empty-title fallback on top of this.
- */
-export function displayWorkbenchTitle(title: string, id: string): string {
-  return title === id || RUN_ID_SHAPE.test(title) ? CHAT_STRINGS.newWorkbenchTitle : title;
-}
diff --git a/apps/web/src/chat/workbench-presence.test.ts b/apps/web/src/chat/workbench-presence.test.ts
deleted file mode 100644
index c4469a197..000000000
--- a/apps/web/src/chat/workbench-presence.test.ts
+++ /dev/null
@@ -1,100 +0,0 @@
-// Pure-logic tests for the who's-here roster's state machine:
-// `nextPresenceRoster` is what `useWorkbenchPresenceRoster` calls on every
-// stream event, kept separate so the rule is testable without mounting
-// anything — mirrors `typing-indicator.tsx`'s own pure/stateful split.
-
-import { describe, expect, test } from "bun:test";
-import {
-  nextPresenceRoster,
-  parsePresenceEvent,
-  parsePresenceSnapshotEvent,
-} from "./workbench-presence";
-
-describe("parsePresenceEvent", () => {
-  test("parses a well-formed chat.presence payload", () => {
-    expect(
-      parsePresenceEvent({
-        principalId: "prn_alice",
-        state: "online",
-        lastActiveAt: "2026-01-01T00:00:00Z",
-      }),
-    ).toEqual({
-      principalId: "prn_alice",
-      state: "online",
-      lastActiveAt: "2026-01-01T00:00:00Z",
-    });
-  });
-
-  test("rejects a malformed payload rather than crashing", () => {
-    expect(parsePresenceEvent(null)).toBeNull();
-    expect(parsePresenceEvent({})).toBeNull();
-    expect(parsePresenceEvent({ principalId: "x", state: "away" })).toBeNull();
-  });
-});
-
-describe("parsePresenceSnapshotEvent", () => {
-  test("parses a well-formed roster", () => {
-    expect(
-      parsePresenceSnapshotEvent({
-        members: [{ principalId: "prn_alice", lastActiveAt: "2026-01-01T00:00:00Z" }],
-      }),
-    ).toEqual([{ principalId: "prn_alice", lastActiveAt: "2026-01-01T00:00:00Z" }]);
-  });
-
-  test("rejects a malformed roster rather than crashing", () => {
-    expect(parsePresenceSnapshotEvent({ members: "nope" })).toBeNull();
-    expect(parsePresenceSnapshotEvent({ members: [{ principalId: "x" }] })).toBeNull();
-  });
-});
-
-describe("nextPresenceRoster", () => {
-  test("a snapshot replaces the roster outright", () => {
-    const current = [{ principalId: "prn_stale", lastActiveAt: "t0" }];
-    const next = nextPresenceRoster(current, {
-      eventType: "chat.presence.snapshot",
-      data: {
-        members: [{ principalId: "prn_alice", lastActiveAt: "t1" }],
-      },
-    });
-    expect(next).toEqual([{ principalId: "prn_alice", lastActiveAt: "t1" }]);
-  });
-
-  test("an online delta for a new principal appends them", () => {
-    const next = nextPresenceRoster([], {
-      eventType: "chat.presence",
-      data: { principalId: "prn_alice", state: "online", lastActiveAt: "t1" },
-    });
-    expect(next).toEqual([{ principalId: "prn_alice", lastActiveAt: "t1" }]);
-  });
-
-  test("an online delta for an already-present principal refreshes lastActiveAt in place", () => {
-    const current = [{ principalId: "prn_alice", lastActiveAt: "t1" }];
-    const next = nextPresenceRoster(current, {
-      eventType: "chat.presence",
-      data: { principalId: "prn_alice", state: "online", lastActiveAt: "t2" },
-    });
-    expect(next).toEqual([{ principalId: "prn_alice", lastActiveAt: "t2" }]);
-  });
-
-  test("an offline delta drops the principal", () => {
-    const current = [
-      { principalId: "prn_alice", lastActiveAt: "t1" },
-      { principalId: "prn_bob", lastActiveAt: "t1" },
-    ];
-    const next = nextPresenceRoster(current, {
-      eventType: "chat.presence",
-      data: { principalId: "prn_alice", state: "offline", lastActiveAt: "t2" },
-    });
-    expect(next).toEqual([{ principalId: "prn_bob", lastActiveAt: "t1" }]);
-  });
-
-  test("any other event type leaves the roster untouched", () => {
-    const current = [{ principalId: "prn_alice", lastActiveAt: "t1" }];
-    expect(nextPresenceRoster(current, { eventType: "chat.typing", data: {} })).toBe(current);
-  });
-
-  test("a malformed delta leaves the roster untouched", () => {
-    const current = [{ principalId: "prn_alice", lastActiveAt: "t1" }];
-    expect(nextPresenceRoster(current, { eventType: "chat.presence", data: null })).toBe(current);
-  });
-});
diff --git a/apps/web/src/chat/workbench-presence.ts b/apps/web/src/chat/workbench-presence.ts
deleted file mode 100644
index 714fe4473..000000000
--- a/apps/web/src/chat/workbench-presence.ts
+++ /dev/null
@@ -1,109 +0,0 @@
-// A workbench's live "who's here" roster, driven off the same `/stream`
-// connection as every other live update — never a second
-// connection or an HTTP heartbeat poll. `chat.presence.snapshot` seeds the
-// roster the moment the stream opens; `chat.presence` deltas
-// (`packages/chat/src/workbench-presence.ts`) keep it current from there.
-// The one thing the stream can't tell this reader — that a backgrounded
-// tab is still theirs — is `POST /workbenches/:id/presence`'s job (see
-// `pingWorkbenchPresence` in `./api.ts`), called on real activity rather
-// than polled on an interval.
-
-import { useEffect, useState } from "react";
-
-export type PresenceRosterEntry = {
-  readonly principalId: string;
-  readonly lastActiveAt: string;
-};
-
-/** Parses a `chat.presence` SSE payload at the trust boundary — the same
- * narrow-parse idiom `typing-indicator.tsx`'s `parseTypingEvent` uses. */
-export function parsePresenceEvent(
-  data: unknown,
-): (PresenceRosterEntry & { readonly state: "online" | "offline" }) | null {
-  if (typeof data !== "object" || data === null) return null;
-  const record = data as Record<string, unknown>;
-  const principalId = record.principalId;
-  const state = record.state;
-  const lastActiveAt = record.lastActiveAt;
-  if (
-    typeof principalId !== "string" ||
-    typeof lastActiveAt !== "string" ||
-    (state !== "online" && state !== "offline")
-  ) {
-    return null;
-  }
-  return { principalId, state, lastActiveAt };
-}
-
-/** Parses a `chat.presence.snapshot` SSE payload — the one-time roster a
- * freshly opened stream is handed before any delta. */
-export function parsePresenceSnapshotEvent(data: unknown): readonly PresenceRosterEntry[] | null {
-  if (typeof data !== "object" || data === null) return null;
-  const members = (data as Record<string, unknown>).members;
-  if (!Array.isArray(members)) return null;
-  const parsed: PresenceRosterEntry[] = [];
-  for (const entry of members) {
-    if (typeof entry !== "object" || entry === null) return null;
-    const principalId = (entry as Record<string, unknown>).principalId;
-    const lastActiveAt = (entry as Record<string, unknown>).lastActiveAt;
-    if (typeof principalId !== "string" || typeof lastActiveAt !== "string") {
-      return null;
-    }
-    parsed.push({ principalId, lastActiveAt });
-  }
-  return parsed;
-}
-
-/**
- * The roster's whole state machine, pure and testable without mounting
- * anything — mirrors `typing-indicator.tsx`'s `nextTypingState`. A
- * snapshot replaces the roster outright; a delta upserts an "online"
- * member or drops an "offline" one; any other event leaves it untouched.
- */
-export function nextPresenceRoster(
-  current: readonly PresenceRosterEntry[],
-  event: { readonly eventType: string; readonly data: unknown },
-): readonly PresenceRosterEntry[] {
-  if (event.eventType === "chat.presence.snapshot") {
-    const parsed = parsePresenceSnapshotEvent(event.data);
-    return parsed ?? current;
-  }
-  if (event.eventType === "chat.presence") {
-    const parsed = parsePresenceEvent(event.data);
-    if (parsed === null) return current;
-    if (parsed.state === "offline") {
-      return current.filter((member) => member.principalId !== parsed.principalId);
-    }
-    const existingIndex = current.findIndex((member) => member.principalId === parsed.principalId);
-    const entry: PresenceRosterEntry = {
-      principalId: parsed.principalId,
-      lastActiveAt: parsed.lastActiveAt,
-    };
-    if (existingIndex === -1) return [...current, entry];
-    return current.map((member, index) => (index === existingIndex ? entry : member));
-  }
-  return current;
-}
-
-/**
- * Owns the who's-here roster end to end: feed it every stream event
- * (`chat-workspace.tsx` already sees them all) and it tracks who's live.
- * `workbenchId` resets the roster on a workbench switch — a snapshot from
- * the workbench just left means nothing here.
- */
-export function useWorkbenchPresenceRoster(workbenchId: string | null): {
-  readonly roster: readonly PresenceRosterEntry[];
-  readonly handleStreamEvent: (eventType: string, data: unknown) => void;
-} {
-  const [roster, setRoster] = useState<readonly PresenceRosterEntry[]>([]);
-
-  useEffect(() => {
-    setRoster([]);
-  }, [workbenchId]);
-
-  function handleStreamEvent(eventType: string, data: unknown) {
-    setRoster((current) => nextPresenceRoster(current, { eventType, data }));
-  }
-
-  return { roster, handleStreamEvent };
-}
diff --git a/apps/web/src/chat/workbench-settings/agents-section.test.ts b/apps/web/src/chat/workbench-settings/agents-section.test.ts
deleted file mode 100644
index f144fb283..000000000
--- a/apps/web/src/chat/workbench-settings/agents-section.test.ts
+++ /dev/null
@@ -1,95 +0,0 @@
-// EMIL #8: the History table's raw backend commit message names
-// the agent in full-sentence form and repeats verbatim across seed rows —
-// these are the pure pieces that turn it into a short per-row change
-// summary and soften repeated runs, independent of the DOM-mounted
-// composition tests in `test/agents-section.test.tsx`.
-
-import { describe, expect, test } from "bun:test";
-
-import { collapseHistoryVersions, summarizeHistoryMessage } from "./agents-section";
-import type { AgentVersion } from "../api";
-
-function version(overrides: Partial<AgentVersion> = {}): AgentVersion {
-  return {
-    commitSha: "sha1",
-    message: "Update agent instructions for Myra",
-    author: "Ada",
-    committedAtIso: "2026-08-01T00:00:00.000Z",
-    current: false,
-    ...overrides,
-  };
-}
-
-describe("summarizeHistoryMessage", () => {
-  test("instructions and skills updates read as a short summary, not the full sentence", () => {
-    expect(summarizeHistoryMessage("Update agent instructions for Myra")).toBe(
-      "Instructions updated",
-    );
-    expect(summarizeHistoryMessage("Update agent skills for Myra")).toBe("Skills updated");
-  });
-
-  test("a capability addition names what was added", () => {
-    expect(summarizeHistoryMessage("Add @corbits/example-tools to Myra")).toBe(
-      "Added tool: @corbits/example-tools",
-    );
-    expect(summarizeHistoryMessage("Add research skill to Myra")).toBe("Added skill: research");
-    expect(summarizeHistoryMessage("Set Myra's model to anthropic/claude-sonnet")).toBe(
-      "Model set to anthropic/claude-sonnet",
-    );
-  });
-
-  test("restore and creation read as their own summaries", () => {
-    expect(summarizeHistoryMessage("Restore agent Myra to a1b2c3d4")).toBe("Restored from history");
-    expect(summarizeHistoryMessage("Define agent Myra")).toBe("Agent created");
-  });
-
-  test("an unrecognized message falls back to itself rather than going blank", () => {
-    expect(summarizeHistoryMessage("Something new entirely")).toBe("Something new entirely");
-  });
-});
-
-describe("collapseHistoryVersions", () => {
-  test("consecutive identical seed rows collapse into one, with a repeat count", () => {
-    const rows = collapseHistoryVersions([
-      version({ commitSha: "sha3", current: true }),
-      version({ commitSha: "sha2" }),
-      version({ commitSha: "sha1" }),
-    ]);
-
-    expect(rows).toHaveLength(2);
-    expect(rows[0]).toMatchObject({
-      commitSha: "sha3",
-      current: true,
-      repeatCount: 1,
-    });
-    expect(rows[1]).toMatchObject({
-      commitSha: "sha2",
-      summary: "Instructions updated",
-      repeatCount: 2,
-    });
-  });
-
-  test("the current row never collapses into a neighbor", () => {
-    const rows = collapseHistoryVersions([
-      version({ commitSha: "sha2", current: true }),
-      version({ commitSha: "sha1", current: false }),
-    ]);
-
-    expect(rows).toHaveLength(2);
-    expect(rows[0]?.current).toBe(true);
-    expect(rows[0]?.repeatCount).toBe(1);
-  });
-
-  test("a different author or change never collapses together", () => {
-    const rows = collapseHistoryVersions([
-      version({ commitSha: "sha2", message: "Update agent skills for Myra" }),
-      version({
-        commitSha: "sha1",
-        message: "Update agent instructions for Myra",
-      }),
-    ]);
-
-    expect(rows).toHaveLength(2);
-    expect(rows.map((row) => row.repeatCount)).toEqual([1, 1]);
-  });
-});
diff --git a/apps/web/src/chat/workbench-settings/agents-section.tsx b/apps/web/src/chat/workbench-settings/agents-section.tsx
deleted file mode 100644
index 157b584a0..000000000
--- a/apps/web/src/chat/workbench-settings/agents-section.tsx
+++ /dev/null
@@ -1,938 +0,0 @@
-// Agents: master-detail over every agent participant this workbench has
-//. The list (every invited agent, Invite agent, the autonomy
-// callout) is the whole surface until one is picked; clicking a row opens
-// that agent's detail — the editor the old, separate "Myra" tab rendered,
-// generalized to any agent: name/instructions (`getAgentInstructions`/
-// `updateAgentInstructions`, `@corbits/agent-directory`'s own routes, a
-// different backend than every other section here, which all PATCH
-// through the workbench settings surface's top-bar Save), Capabilities
-// (tools/skills, plus a model picker fed from this tenant's resolved,
-// workspace-wide inference catalog — see `CapabilitiesBlock` below), and
-// History (every commit to the agent's instructions/capabilities, with
-// restore). A load failure renders as an inline reason, never a fake save.
-// Selection is host-owned when `onEntityIdChange` is passed (workbench URL
-// `/settings/agents/:definitionId`); otherwise the section keeps a local
-// selection for standalone mounts.
-
-import { useEffect, useState } from "react";
-import {
-  Button,
-  EmptyState,
-  Input,
-  Skeleton,
-  Table,
-  TableBody,
-  TableCell,
-  TableHead,
-  TableHeader,
-  TableRow,
-  formatRelativeTime,
-  toast,
-} from "@corbits/react-ui";
-import { chatCapableModels, getResolvedCatalog, providerDisplayName } from "@/settings/inference";
-import type { ModelInfo } from "@/settings/inference";
-import { ArrowLeft, CaretRight, WarningCircle } from "@/lib/icons";
-import { CorbitAvatar } from "../avatar";
-
-import {
-  addAgentCapability,
-  describeChatError,
-  getAgentInstructions,
-  listAgentVersions,
-  listCapabilityInventory,
-  listWorkbenchAgents,
-  refreshWorkbenchAgent,
-  restoreAgentVersion,
-  updateAgentInstructions,
-} from "../api";
-import type {
-  AgentDetail,
-  AgentVersion,
-  CapabilityAddition,
-  CapabilityInventory,
-  WorkbenchAgent,
-} from "../api";
-import { CHAT_STRINGS } from "../strings";
-
-type ListState =
-  | { readonly kind: "loading" }
-  | { readonly kind: "error"; readonly message: string }
-  | { readonly kind: "ready"; readonly agents: readonly WorkbenchAgent[] };
-
-export function AgentsSection({
-  tenantId,
-  workbenchId,
-  entityId = null,
-  onEntityIdChange,
-}: {
-  readonly tenantId: string;
-  readonly workbenchId: string;
-  /** Host-controlled selection (`definitionId`) — driven from the URL when
-   * the workbench settings surface is deep-linked. Only honored when
-   * `onEntityIdChange` is also passed (that callback is the controlled-mode
-   * gate). */
-  readonly entityId?: string | null;
-  /** Fired when the user opens or closes an agent detail so the host can
-   * reflect it in the URL. Passing this opts into host-owned selection;
-   * omitting it keeps selection local to this section. */
-  readonly onEntityIdChange?: (definitionId: string | null) => void;
-}) {
-  const [state, setState] = useState<ListState>({ kind: "loading" });
-  const [localEntityId, setLocalEntityId] = useState<string | null>(null);
-  const selectedId = onEntityIdChange !== undefined ? (entityId ?? null) : localEntityId;
-
-  useEffect(() => {
-    let cancelled = false;
-    setState({ kind: "loading" });
-    listWorkbenchAgents(tenantId, workbenchId)
-      .then((agents) => {
-        if (!cancelled) setState({ kind: "ready", agents });
-      })
-      .catch((cause: unknown) => {
-        if (cancelled) return;
-        setState({
-          kind: "error",
-          message: describeChatError(cause, "Couldn't load the agents."),
-        });
-      });
-    return () => {
-      cancelled = true;
-    };
-  }, [tenantId, workbenchId]);
-
-  useEffect(() => {
-    if (state.kind !== "ready") return;
-    if (selectedId === null) return;
-    if (state.agents.some((agent) => agent.definitionId === selectedId)) {
-      return;
-    }
-    if (onEntityIdChange !== undefined) {
-      onEntityIdChange(null);
-      return;
-    }
-    setLocalEntityId(null);
-  }, [state, selectedId, onEntityIdChange]);
-
-  function select(definitionId: string | null) {
-    if (onEntityIdChange !== undefined) {
-      onEntityIdChange(definitionId);
-      return;
-    }
-    setLocalEntityId(definitionId);
-  }
-
-  if (state.kind === "loading") {
-    return <Skeleton className="query-skeleton" />;
-  }
-
-  if (state.kind === "error") {
-    return (
-      <EmptyState
-        icon={<WarningCircle />}
-        title="Couldn't load agents"
-        description={state.message}
-      />
-    );
-  }
-
-  const selected =
-    selectedId === null
-      ? null
-      : (state.agents.find((agent) => agent.definitionId === selectedId) ?? null);
-
-  if (selected !== null) {
-    return (
-      <div className="workbench-settings-pane">
-        <button type="button" className="chat-settings-agent-back" onClick={() => select(null)}>
-          <ArrowLeft aria-hidden="true" />
-          {CHAT_STRINGS.workbenchSettingsAgentsBackAction}
-        </button>
-        <AgentDetailEditor tenantId={tenantId} workbenchId={workbenchId} agent={selected} />
-      </div>
-    );
-  }
-
-  return (
-    <div className="workbench-settings-pane">
-      <div className="chat-settings-field">
-        <span>{CHAT_STRINGS.workbenchSettingsAgentsLabel}</span>
-        <p className="chat-settings-field-hint">{CHAT_STRINGS.workbenchSettingsAgentsInviteHint}</p>
-        {state.agents.length === 0 ? (
-          <p className="chat-settings-field-hint">{CHAT_STRINGS.workbenchSettingsNoAgents}</p>
-        ) : (
-          <ul className="chat-settings-participants-list">
-            {state.agents.map((agent) => (
-              <li key={agent.address}>
-                <button
-                  type="button"
-                  className="chat-settings-agent-picker-row"
-                  onClick={() => select(agent.definitionId)}
-                >
-                  @{agent.handle}
-                  <CaretRight
-                    aria-hidden="true"
-                    className="chat-settings-agent-picker-row-chevron"
-                  />
-                </button>
-              </li>
-            ))}
-          </ul>
-        )}
-      </div>
-      <div className="chat-settings-callout">
-        <span className="chat-settings-callout-label">
-          {CHAT_STRINGS.workbenchSettingsAutonomyTitle}
-        </span>
-        <p>{CHAT_STRINGS.workbenchSettingsAutonomyBody}</p>
-      </div>
-    </div>
-  );
-}
-
-type EditorState =
-  | { readonly kind: "loading" }
-  | { readonly kind: "error"; readonly message: string }
-  | { readonly kind: "ready"; readonly detail: AgentDetail };
-
-function AgentDetailEditor({
-  tenantId,
-  workbenchId,
-  agent,
-}: {
-  readonly tenantId: string;
-  readonly workbenchId: string;
-  readonly agent: WorkbenchAgent;
-}) {
-  const [state, setState] = useState<EditorState>({ kind: "loading" });
-  const [name, setName] = useState("");
-  const [instructions, setInstructions] = useState("");
-  const [saving, setSaving] = useState(false);
-  const [saveError, setSaveError] = useState<string | null>(null);
-  const [catalogState, setCatalogState] = useState<CatalogState>({
-    kind: "loading",
-  });
-  const [catalogReloadKey, setCatalogReloadKey] = useState(0);
-
-  useEffect(() => {
-    let cancelled = false;
-    setCatalogState({ kind: "loading" });
-    getResolvedCatalog(tenantId)
-      .then((models) => {
-        if (!cancelled) setCatalogState({ kind: "ready", models });
-      })
-      .catch((cause: unknown) => {
-        if (cancelled) return;
-        setCatalogState({
-          kind: "error",
-          message: describeChatError(cause, CHAT_STRINGS.workbenchSettingsAgentDetailCatalogError),
-        });
-      });
-    return () => {
-      cancelled = true;
-    };
-  }, [tenantId, catalogReloadKey]);
-
-  useEffect(() => {
-    let cancelled = false;
-    getAgentInstructions(tenantId, agent.definitionId)
-      .then((detail) => {
-        if (cancelled) return;
-        setName(detail.name);
-        setInstructions(detail.systemPrompt);
-        setState({ kind: "ready", detail });
-      })
-      .catch((cause: unknown) => {
-        if (cancelled) return;
-        setState({
-          kind: "error",
-          message: describeChatError(cause, "Couldn't load the agent."),
-        });
-      });
-    return () => {
-      cancelled = true;
-    };
-  }, [tenantId, agent.definitionId]);
-
-  const label =
-    state.kind === "ready" && state.detail.name.trim() !== ""
-      ? state.detail.name
-      : `@${agent.handle}`;
-
-  if (state.kind === "loading") {
-    return <Skeleton className="query-skeleton" />;
-  }
-
-  // No backing route succeeded for this agent's definition — render the
-  // reason, not a form with nothing behind it. Never a fake save.
-  if (state.kind === "error") {
-    return (
-      <EmptyState
-        icon={<WarningCircle />}
-        title={CHAT_STRINGS.workbenchSettingsAgentDetailLoadError}
-        description={state.message}
-      />
-    );
-  }
-
-  const dirty = name !== state.detail.name || instructions !== state.detail.systemPrompt;
-
-  function handleCancel() {
-    if (state.kind !== "ready") return;
-    setName(state.detail.name);
-    setInstructions(state.detail.systemPrompt);
-    setSaveError(null);
-  }
-
-  function handleSave() {
-    if (state.kind !== "ready" || !dirty) return;
-    setSaving(true);
-    setSaveError(null);
-    updateAgentInstructions(tenantId, agent.definitionId, {
-      name,
-      systemPrompt: instructions,
-    })
-      .then((saved) =>
-        refreshWorkbenchAgent(tenantId, workbenchId, agent.address).then(() => saved),
-      )
-      .then((saved) => {
-        toast(CHAT_STRINGS.workbenchSettingsAgentDetailSavedToast);
-        setState((prev) =>
-          prev.kind === "ready"
-            ? {
-                kind: "ready",
-                detail: { ...prev.detail, ...saved },
-              }
-            : prev,
-        );
-      })
-      .catch(() => setSaveError(CHAT_STRINGS.workbenchSettingsAgentDetailSaveError))
-      .finally(() => setSaving(false));
-  }
-
-  return (
-    <div className="chat-settings-agent-block">
-      <div className="flex items-center gap-3">
-        <CorbitAvatar size="lg" ariaLabel={label} />
-        <h3 className="chat-settings-agent-block-title">{label}</h3>
-      </div>
-
-      <ModelSelect
-        tenantId={tenantId}
-        workbenchId={workbenchId}
-        agent={agent}
-        detail={state.detail}
-        catalogState={catalogState}
-        onRetryCatalog={() => setCatalogReloadKey((value) => value + 1)}
-        onChanged={(detail) => setState({ kind: "ready", detail })}
-      />
-
-      <label className="chat-settings-field">
-        <span>{CHAT_STRINGS.workbenchSettingsAgentDetailNameLabel}</span>
-        <Input value={name} onChange={(event) => setName(event.target.value)} />
-      </label>
-      <label className="chat-settings-field">
-        <span>{CHAT_STRINGS.workbenchSettingsAgentDetailInstructionsLabel}</span>
-        <textarea
-          className="chat-textarea"
-          value={instructions}
-          onChange={(event) => setInstructions(event.target.value)}
-          rows={10}
-        />
-      </label>
-      <p className="chat-settings-field-hint">
-        {CHAT_STRINGS.workbenchSettingsAgentDetailInstructionsHint}
-      </p>
-      {saveError !== null ? (
-        <p className="chat-dialog-error" role="alert">
-          {saveError}
-        </p>
-      ) : null}
-      <div className="chat-settings-field-actions">
-        <Button type="button" variant="outline" onClick={handleCancel} disabled={!dirty || saving}>
-          {CHAT_STRINGS.workbenchSettingsAgentDetailCancel}
-        </Button>
-        <Button type="button" variant="primary" onClick={handleSave} disabled={!dirty || saving}>
-          {saving
-            ? CHAT_STRINGS.workbenchSettingsAgentDetailSaving
-            : CHAT_STRINGS.workbenchSettingsAgentDetailSave}
-        </Button>
-      </div>
-
-      <CapabilitiesBlock
-        tenantId={tenantId}
-        workbenchId={workbenchId}
-        agent={agent}
-        detail={state.detail}
-        catalogState={catalogState}
-        onChanged={(detail) => setState({ kind: "ready", detail })}
-      />
-
-      <HistoryBlock
-        tenantId={tenantId}
-        workbenchId={workbenchId}
-        agent={agent}
-        onRestored={(detail) => {
-          setName(detail.name);
-          setInstructions(detail.systemPrompt);
-          setState({ kind: "ready", detail });
-        }}
-      />
-    </div>
-  );
-}
-
-// --- Capabilities (tools, skills, and — the per-agent inference picker —
-// model, fed from this tenant's resolved catalog: the workspace-wide pool
-// of providers actually connected, the same read the Models settings
-// section itself resolves from, never a second store of "what's
-// available") ---
-
-type InventoryState =
-  | { readonly kind: "loading" }
-  | { readonly kind: "error" }
-  | { readonly kind: "ready"; readonly inventory: CapabilityInventory };
-
-type ModelOption = { readonly canonicalName: string; readonly label: string };
-
-type CatalogState =
-  | { readonly kind: "loading" }
-  | { readonly kind: "error"; readonly message: string }
-  | { readonly kind: "ready"; readonly models: readonly ModelInfo[] };
-
-/** Only a model with at least one offering is actually launchable for this
- * tenant — an entry with none has no provider connected anywhere up the
- * ancestor chain, so it is left off the picker rather than offered to fail
- * at launch. Embedding / Hugging Face / GGUF path names are also omitted
- * via `chatCapableModels`. Labeled by its top (highest-priority)
- * offering's provider — the same one `getResolvedCatalog`'s resolution
- * would pick. */
-function connectedModelOptions(
-  models: readonly ModelInfo[],
-  alreadySet: string | undefined,
-): readonly ModelOption[] {
-  return chatCapableModels(models)
-    .filter((model) => model.offerings.length > 0 && model.canonicalName !== alreadySet)
-    .map((model) => {
-      const topOffering = model.offerings[0];
-      return {
-        canonicalName: model.canonicalName,
-        label: CHAT_STRINGS.workbenchSettingsAgentDetailModelOption(
-          model.displayName ?? model.canonicalName,
-          topOffering === undefined ? "" : providerDisplayName(topOffering.providerName),
-        ),
-      };
-    });
-}
-
-/**
- * The obvious, top-of-detail way to change an agent's model —
- * the "Add a capability" flow below stays for tools/skills/models added
- * one at a time, but a model is a property every agent already has one
- * of, not an optional add-on, so it gets its own labeled control that
- * shows the current model and saves the moment a different one is
- * chosen. Saves through the exact same `addAgentCapability({ kind:
- * "model" })` path the Add-a-capability flow already uses — one write
- * path, two entry points.
- */
-function ModelSelect({
-  tenantId,
-  workbenchId,
-  agent,
-  detail,
-  catalogState,
-  onRetryCatalog,
-  onChanged,
-}: {
-  readonly tenantId: string;
-  readonly workbenchId: string;
-  readonly agent: WorkbenchAgent;
-  readonly detail: AgentDetail;
-  readonly catalogState: CatalogState;
-  readonly onRetryCatalog: () => void;
-  readonly onChanged: (detail: AgentDetail) => void;
-}) {
-  const [saving, setSaving] = useState(false);
-  const [error, setError] = useState<string | null>(null);
-
-  const options =
-    catalogState.kind === "ready" ? connectedModelOptions(catalogState.models, undefined) : [];
-
-  // The currently-set model may no longer carry a connected offering
-  // (its provider was disconnected) — still list it, disabled, rather
-  // than silently drop the value the select is showing.
-  const currentOptions =
-    detail.model !== undefined && !options.some((option) => option.canonicalName === detail.model)
-      ? [{ canonicalName: detail.model, label: detail.model }, ...options]
-      : options;
-
-  function handleChange(canonicalName: string) {
-    if (canonicalName === "" || canonicalName === detail.model) return;
-    setSaving(true);
-    setError(null);
-    addAgentCapability(tenantId, agent.definitionId, {
-      kind: "model",
-      canonicalName,
-    })
-      .then((capabilities) =>
-        refreshWorkbenchAgent(tenantId, workbenchId, agent.address).then(() => capabilities),
-      )
-      .then((capabilities) => {
-        toast(CHAT_STRINGS.workbenchSettingsAgentDetailSavedToast);
-        onChanged({ ...detail, ...capabilities });
-      })
-      .catch(() => setError(CHAT_STRINGS.workbenchSettingsAgentDetailAddCapabilityError))
-      .finally(() => setSaving(false));
-  }
-
-  return (
-    <label className="chat-settings-field chat-settings-agent-model-select">
-      <span>{CHAT_STRINGS.workbenchSettingsAgentDetailModelLabel}</span>
-      <select
-        value={detail.model ?? ""}
-        onChange={(event) => handleChange(event.target.value)}
-        disabled={saving || catalogState.kind === "loading" || catalogState.kind === "error"}
-      >
-        {detail.model === undefined ? (
-          <option value="">{CHAT_STRINGS.workbenchSettingsAgentDetailModelUnset}</option>
-        ) : null}
-        {currentOptions.map((option) => (
-          <option key={option.canonicalName} value={option.canonicalName}>
-            {option.label}
-          </option>
-        ))}
-      </select>
-      {saving ? (
-        <p className="chat-settings-field-hint">
-          {CHAT_STRINGS.workbenchSettingsAgentDetailSaving}
-        </p>
-      ) : null}
-      {catalogState.kind === "ready" && options.length === 0 ? (
-        <p className="chat-settings-field-hint">
-          {CHAT_STRINGS.workbenchSettingsAgentDetailNoConnectedModels}
-        </p>
-      ) : null}
-      {catalogState.kind === "error" ? (
-        <>
-          <p className="chat-dialog-error" role="alert">
-            {catalogState.message}
-          </p>
-          <div className="chat-settings-field-actions">
-            <Button type="button" variant="outline" size="sm" onClick={onRetryCatalog}>
-              {CHAT_STRINGS.workbenchSettingsAgentDetailCatalogRetryAction}
-            </Button>
-            <a href="/settings/connections">
-              {CHAT_STRINGS.workbenchSettingsAgentDetailCatalogSettingsAction}
-            </a>
-          </div>
-        </>
-      ) : null}
-      {error !== null ? (
-        <p className="chat-dialog-error" role="alert">
-          {error}
-        </p>
-      ) : null}
-    </label>
-  );
-}
-
-function CapabilitiesBlock({
-  tenantId,
-  workbenchId,
-  agent,
-  detail,
-  catalogState,
-  onChanged,
-}: {
-  readonly tenantId: string;
-  readonly workbenchId: string;
-  readonly agent: WorkbenchAgent;
-  readonly detail: AgentDetail;
-  readonly catalogState: CatalogState;
-  readonly onChanged: (detail: AgentDetail) => void;
-}) {
-  const [inventoryState, setInventoryState] = useState<InventoryState>({
-    kind: "loading",
-  });
-  const [kind, setKind] = useState<CapabilityAddition["kind"]>("toolPackage");
-  const [choice, setChoice] = useState("");
-  const [adding, setAdding] = useState(false);
-  const [addError, setAddError] = useState<string | null>(null);
-
-  useEffect(() => {
-    let cancelled = false;
-    listCapabilityInventory(tenantId)
-      .then((inventory) => {
-        if (!cancelled) setInventoryState({ kind: "ready", inventory });
-      })
-      .catch(() => {
-        if (!cancelled) setInventoryState({ kind: "error" });
-      });
-    return () => {
-      cancelled = true;
-    };
-  }, [tenantId]);
-
-  const modelOptions =
-    catalogState.kind === "ready" ? connectedModelOptions(catalogState.models, detail.model) : [];
-
-  const options =
-    kind === "toolPackage"
-      ? inventoryState.kind === "ready"
-        ? inventoryState.inventory.toolPackages
-            .map((entry) => entry.name)
-            .filter((name) => !detail.toolPackagePins.some((pin) => pin.name === name))
-        : []
-      : kind === "skill"
-        ? inventoryState.kind === "ready"
-          ? inventoryState.inventory.skills
-              .map((entry) => entry.name)
-              .filter((name) => !detail.skills.includes(name))
-          : []
-        : modelOptions.map((option) => option.canonicalName);
-
-  const optionsLoading =
-    kind === "model" ? catalogState.kind === "loading" : inventoryState.kind === "loading";
-
-  function addition(): CapabilityAddition | undefined {
-    if (choice === "") return undefined;
-    if (kind === "model") return { kind: "model", canonicalName: choice };
-    return { kind, name: choice };
-  }
-
-  function handleAdd() {
-    const next = addition();
-    if (next === undefined) return;
-    setAdding(true);
-    setAddError(null);
-    addAgentCapability(tenantId, agent.definitionId, next)
-      .then((capabilities) =>
-        refreshWorkbenchAgent(tenantId, workbenchId, agent.address).then(() => capabilities),
-      )
-      .then((capabilities) => {
-        toast(CHAT_STRINGS.workbenchSettingsAgentDetailSavedToast);
-        onChanged({ ...detail, ...capabilities });
-        setChoice("");
-      })
-      .catch(() => setAddError(CHAT_STRINGS.workbenchSettingsAgentDetailAddCapabilityError))
-      .finally(() => setAdding(false));
-  }
-
-  const hasCapabilities =
-    detail.toolPackagePins.length > 0 || detail.skills.length > 0 || detail.model !== undefined;
-
-  return (
-    <div className="chat-settings-agent-block-section">
-      <h4>{CHAT_STRINGS.workbenchSettingsAgentDetailCapabilitiesTitle}</h4>
-      <p className="chat-settings-field-hint">
-        {CHAT_STRINGS.workbenchSettingsAgentDetailCapabilitiesHint}
-      </p>
-
-      {hasCapabilities ? (
-        <ul className="chat-settings-capability-list">
-          {detail.toolPackagePins.map((pin) => (
-            <li key={`tool-${pin.name}`}>
-              <span className="chat-settings-capability-chip">{pin.name}</span>
-            </li>
-          ))}
-          {detail.skills.map((skillName) => (
-            <li key={`skill-${skillName}`}>
-              <span className="chat-settings-capability-chip">{skillName}</span>
-            </li>
-          ))}
-          {detail.model !== undefined ? (
-            <li key="model">
-              <span className="chat-settings-capability-chip">
-                {CHAT_STRINGS.workbenchSettingsAgentDetailModelLabel}: {detail.model}
-              </span>
-            </li>
-          ) : null}
-        </ul>
-      ) : (
-        <p className="chat-settings-field-hint">
-          {CHAT_STRINGS.workbenchSettingsAgentDetailNoCapabilities}
-        </p>
-      )}
-
-      {inventoryState.kind === "error" ? (
-        <p className="chat-dialog-error" role="alert">
-          {CHAT_STRINGS.workbenchSettingsAgentDetailCapabilityInventoryError}
-        </p>
-      ) : (
-        <div className="chat-settings-capability-add">
-          <label className="chat-settings-field">
-            <span>{CHAT_STRINGS.workbenchSettingsAgentDetailAddCapabilityLabel}</span>
-            <select
-              value={kind}
-              onChange={(event) => {
-                setKind(event.target.value as CapabilityAddition["kind"]);
-                setChoice("");
-              }}
-            >
-              <option value="toolPackage">
-                {CHAT_STRINGS.workbenchSettingsAgentDetailAddCapabilityKindTool}
-              </option>
-              <option value="skill">
-                {CHAT_STRINGS.workbenchSettingsAgentDetailAddCapabilityKindSkill}
-              </option>
-              <option value="model">
-                {CHAT_STRINGS.workbenchSettingsAgentDetailAddCapabilityKindModel}
-              </option>
-            </select>
-          </label>
-          <label className="chat-settings-field">
-            <span>{CHAT_STRINGS.workbenchSettingsAgentDetailAddCapabilityChoiceLabel}</span>
-            <select
-              value={choice}
-              onChange={(event) => setChoice(event.target.value)}
-              disabled={optionsLoading || options.length === 0}
-            >
-              <option value="">
-                {CHAT_STRINGS.workbenchSettingsAgentDetailAddCapabilityChoicePlaceholder(kind)}
-              </option>
-              {kind === "model"
-                ? modelOptions.map((option) => (
-                    <option key={option.canonicalName} value={option.canonicalName}>
-                      {option.label}
-                    </option>
-                  ))
-                : options.map((option) => (
-                    <option key={option} value={option}>
-                      {option}
-                    </option>
-                  ))}
-            </select>
-          </label>
-          <Button
-            type="button"
-            variant="outline"
-            onClick={handleAdd}
-            disabled={choice === "" || adding}
-          >
-            {adding
-              ? CHAT_STRINGS.workbenchSettingsAgentDetailAddCapabilityAdding
-              : CHAT_STRINGS.workbenchSettingsAgentDetailAddCapabilityButton}
-          </Button>
-        </div>
-      )}
-      {kind === "model" && catalogState.kind === "ready" && modelOptions.length === 0 ? (
-        <p className="chat-settings-field-hint">
-          {CHAT_STRINGS.workbenchSettingsAgentDetailNoConnectedModels}
-        </p>
-      ) : null}
-      {addError !== null ? (
-        <p className="chat-dialog-error" role="alert">
-          {addError}
-        </p>
-      ) : null}
-    </div>
-  );
-}
-
-// --- History ---
-
-/** The backend's own commit message already names the kind of change
- * (`packages/agent-directory/src/routes.ts` and its sibling capability/
- * skill-pin route files), but it's written as a full sentence naming the
- * agent — redundant on a page that's already scoped to this one agent, and
- * repetitive across rows. This turns it into the short change summary the
- * history table actually shows, falling back to the raw
- * message for anything this doesn't recognize rather than hiding it. */
-export function summarizeHistoryMessage(message: string): string {
-  if (/^Update agent instructions for /.test(message)) {
-    return "Instructions updated";
-  }
-  if (/^Update agent skills for /.test(message)) {
-    return "Skills updated";
-  }
-  const skillMatch = /^Add (.+) skill to /.exec(message);
-  if (skillMatch !== null) {
-    return `Added skill: ${skillMatch[1]}`;
-  }
-  const toolMatch = /^Add (.+) to /.exec(message);
-  if (toolMatch !== null) {
-    return `Added tool: ${toolMatch[1]}`;
-  }
-  const modelMatch = /^Set .+'s model to (.+)$/.exec(message);
-  if (modelMatch !== null) {
-    return `Model set to ${modelMatch[1]}`;
-  }
-  if (/^Restore agent .+ to /.test(message)) {
-    return "Restored from history";
-  }
-  if (/^Define agent /.test(message)) {
-    return "Agent created";
-  }
-  return message;
-}
-
-export type HistoryDisplayRow = {
-  readonly commitSha: string;
-  readonly summary: string;
-  readonly author: string;
-  readonly committedAtIso: string;
-  readonly current: boolean;
-  readonly repeatCount: number;
-};
-
-/** Softens a run of consecutive, identically-summarized rows (seed data's
- * repeated "Update agent instructions for X" is the case that prompted
- * this) into one row with a repeat count, rather than a wall of visually
- * identical entries — restoring that row still targets its newest
- * commit. Never collapses across the current version, so "current" always
- * stays its own row. */
-export function collapseHistoryVersions(
-  versions: readonly AgentVersion[],
-): readonly HistoryDisplayRow[] {
-  const rows: HistoryDisplayRow[] = [];
-  for (const version of versions) {
-    const summary = summarizeHistoryMessage(version.message);
-    const last = rows[rows.length - 1];
-    if (
-      last !== undefined &&
-      !last.current &&
-      !version.current &&
-      last.summary === summary &&
-      last.author === version.author
-    ) {
-      rows[rows.length - 1] = { ...last, repeatCount: last.repeatCount + 1 };
-      continue;
-    }
-    rows.push({
-      commitSha: version.commitSha,
-      summary,
-      author: version.author,
-      committedAtIso: version.committedAtIso,
-      current: version.current,
-      repeatCount: 1,
-    });
-  }
-  return rows;
-}
-
-type HistoryState =
-  | { readonly kind: "loading" }
-  | { readonly kind: "error"; readonly message: string }
-  | { readonly kind: "ready"; readonly versions: readonly AgentVersion[] };
-
-function HistoryBlock({
-  tenantId,
-  workbenchId,
-  agent,
-  onRestored,
-}: {
-  readonly tenantId: string;
-  readonly workbenchId: string;
-  readonly agent: WorkbenchAgent;
-  readonly onRestored: (detail: AgentDetail) => void;
-}) {
-  const [state, setState] = useState<HistoryState>({ kind: "loading" });
-  const [restoring, setRestoring] = useState<string | null>(null);
-  const [restoreError, setRestoreError] = useState<string | null>(null);
-
-  function reload() {
-    setState({ kind: "loading" });
-    listAgentVersions(tenantId, agent.definitionId)
-      .then((versions) => setState({ kind: "ready", versions }))
-      .catch((cause: unknown) =>
-        setState({
-          kind: "error",
-          message: describeChatError(
-            cause,
-            CHAT_STRINGS.workbenchSettingsAgentDetailHistoryLoadError,
-          ),
-        }),
-      );
-  }
-
-  useEffect(reload, [tenantId, agent.definitionId]);
-
-  function handleRestore(commitSha: string) {
-    setRestoring(commitSha);
-    setRestoreError(null);
-    restoreAgentVersion(tenantId, agent.definitionId, commitSha)
-      .then((detail) =>
-        refreshWorkbenchAgent(tenantId, workbenchId, agent.address).then(() => detail),
-      )
-      .then((detail) => {
-        toast(CHAT_STRINGS.workbenchSettingsAgentDetailSavedToast);
-        onRestored(detail);
-        reload();
-      })
-      .catch(() => setRestoreError(CHAT_STRINGS.workbenchSettingsAgentDetailHistoryRestoreError))
-      .finally(() => setRestoring(null));
-  }
-
-  return (
-    <div className="chat-settings-agent-block-section">
-      <h4>{CHAT_STRINGS.workbenchSettingsAgentDetailHistoryTitle}</h4>
-      <p className="chat-settings-field-hint">
-        {CHAT_STRINGS.workbenchSettingsAgentDetailHistoryHint}
-      </p>
-
-      {state.kind === "loading" ? (
-        <Skeleton className="query-skeleton" />
-      ) : state.kind === "error" ? (
-        <p className="chat-dialog-error" role="alert">
-          {state.message}
-        </p>
-      ) : state.versions.length === 0 ? (
-        <p className="chat-settings-field-hint">
-          {CHAT_STRINGS.workbenchSettingsAgentDetailHistoryEmpty}
-        </p>
-      ) : (
-        <Table>
-          <TableHeader>
-            <TableRow>
-              <TableHead>Change</TableHead>
-              <TableHead>Who</TableHead>
-              <TableHead>When</TableHead>
-              <TableHead className="text-right">Action</TableHead>
-            </TableRow>
-          </TableHeader>
-          <TableBody>
-            {collapseHistoryVersions(state.versions).map((row) => (
-              <TableRow
-                key={row.commitSha}
-                className={row.current ? "chat-settings-history-row-current" : undefined}
-              >
-                <TableCell className="text-sm" title={row.commitSha}>
-                  {row.summary}
-                  {row.repeatCount > 1 ? (
-                    <span className="chat-settings-history-repeat-count">×{row.repeatCount}</span>
-                  ) : null}
-                  {row.current ? (
-                    <span className="chat-settings-history-current-label">
-                      {CHAT_STRINGS.workbenchSettingsAgentDetailHistoryCurrent}
-                    </span>
-                  ) : null}
-                </TableCell>
-                <TableCell className="text-sm text-muted-foreground">{row.author}</TableCell>
-                <TableCell className="text-sm text-muted-foreground">
-                  {formatRelativeTime(row.committedAtIso, Date.now())}
-                </TableCell>
-                <TableCell className="text-right">
-                  <Button
-                    type="button"
-                    size="sm"
-                    variant="outline"
-                    disabled={row.current || restoring !== null}
-                    onClick={() => handleRestore(row.commitSha)}
-                  >
-                    {restoring === row.commitSha
-                      ? CHAT_STRINGS.workbenchSettingsAgentDetailHistoryRestoring
-                      : CHAT_STRINGS.workbenchSettingsAgentDetailHistoryRestore}
-                  </Button>
-                </TableCell>
-              </TableRow>
-            ))}
-          </TableBody>
-        </Table>
-      )}
-      {restoreError !== null ? (
-        <p className="chat-dialog-error" role="alert">
-          {restoreError}
-        </p>
-      ) : null}
-    </div>
-  );
-}
diff --git a/apps/web/src/chat/workbench-settings/context-window.test.ts b/apps/web/src/chat/workbench-settings/context-window.test.ts
deleted file mode 100644
index 6a41630fd..000000000
--- a/apps/web/src/chat/workbench-settings/context-window.test.ts
+++ /dev/null
@@ -1,29 +0,0 @@
-import { describe, expect, test } from "bun:test";
-
-import { contextWindowControlState, contextWindowPatchValue } from "./context-window";
-
-describe("contextWindowControlState", () => {
-  test("an inheriting workbench renders the bench-default mode with the resolved value", () => {
-    expect(contextWindowControlState({ value: 20, source: "inherit" })).toEqual({
-      mode: "inherit",
-      displayValue: 20,
-    });
-  });
-
-  test("an overriding workbench renders the override mode with its own value", () => {
-    expect(contextWindowControlState({ value: 5, source: "override" })).toEqual({
-      mode: "override",
-      displayValue: 5,
-    });
-  });
-});
-
-describe("contextWindowPatchValue", () => {
-  test("switching to inherit always clears the override to null", () => {
-    expect(contextWindowPatchValue("inherit", 5)).toBeNull();
-  });
-
-  test("override mode sends the field's own value", () => {
-    expect(contextWindowPatchValue("override", 7)).toBe(7);
-  });
-});
diff --git a/apps/web/src/chat/workbench-settings/context-window.ts b/apps/web/src/chat/workbench-settings/context-window.ts
deleted file mode 100644
index 36e56b093..000000000
--- a/apps/web/src/chat/workbench-settings/context-window.ts
+++ /dev/null
@@ -1,30 +0,0 @@
-// Conversation-memory control's own resolution, independent of React:
-// what mode the toggle should show, what value it should PATCH.
-
-export type ContextWindowMode = "inherit" | "override";
-
-/**
- * The two-state control's own resolution, independent of React: what mode
- * the toggle should show and what number the (possibly-disabled) numeric
- * field should display — the "Use bench default (N)" vs override state a
- * workbench's resolved context window folds down to.
- */
-export function contextWindowControlState(resolved: {
-  readonly value: number;
-  readonly source: "inherit" | "override";
-}): { readonly mode: ContextWindowMode; readonly displayValue: number } {
-  return { mode: resolved.source, displayValue: resolved.value };
-}
-
-/**
- * What a context-window edit should PATCH: switching to "inherit" always
- * clears the override back to `null` regardless of whatever the field shows;
- * switching to (or staying on) "override" sends the field's own value,
- * clamped and validated the same way the panel's numeric input already is.
- */
-export function contextWindowPatchValue(
-  mode: ContextWindowMode,
-  overrideValue: number,
-): number | null {
-  return mode === "inherit" ? null : overrideValue;
-}
diff --git a/apps/web/src/chat/workbench-settings/danger-section.tsx b/apps/web/src/chat/workbench-settings/danger-section.tsx
deleted file mode 100644
index a4420dcd8..000000000
--- a/apps/web/src/chat/workbench-settings/danger-section.tsx
+++ /dev/null
@@ -1,17 +0,0 @@
-// Danger zone section: archive is not wired to a real endpoint yet — same
-// callout copy the dialog shipped, just re-housed.
-
-import { CHAT_STRINGS } from "../strings";
-
-export function DangerSection() {
-  return (
-    <div className="workbench-settings-pane">
-      <div className="chat-settings-callout chat-settings-callout-danger">
-        <span className="chat-settings-callout-label">
-          {CHAT_STRINGS.workbenchSettingsArchiveTitle}
-        </span>
-        <p>{CHAT_STRINGS.workbenchSettingsArchiveBody}</p>
-      </div>
-    </div>
-  );
-}
diff --git a/apps/web/src/chat/workbench-settings/general-section.tsx b/apps/web/src/chat/workbench-settings/general-section.tsx
deleted file mode 100644
index 942d423e8..000000000
--- a/apps/web/src/chat/workbench-settings/general-section.tsx
+++ /dev/null
@@ -1,105 +0,0 @@
-// General section: identity (name, purpose) and behavior (pinned, context
-// window).
-
-import { Input, Switch } from "@corbits/react-ui";
-
-import { CHAT_STRINGS } from "../strings";
-import type { ContextWindowMode } from "./context-window";
-
-export function GeneralSection({
-  workbenchId,
-  name,
-  onNameChange,
-  purpose,
-  onPurposeChange,
-  pinned,
-  onPinnedChange,
-  contextWindowMode,
-  onContextWindowModeChange,
-  contextWindowInput,
-  onContextWindowInputChange,
-  benchDefault,
-}: {
-  readonly workbenchId: string;
-  readonly name: string;
-  readonly onNameChange: (value: string) => void;
-  readonly purpose: string;
-  readonly onPurposeChange: (value: string) => void;
-  readonly pinned: boolean;
-  readonly onPinnedChange: (value: boolean) => void;
-  readonly contextWindowMode: ContextWindowMode;
-  readonly onContextWindowModeChange: (mode: ContextWindowMode) => void;
-  readonly contextWindowInput: string;
-  readonly onContextWindowInputChange: (value: string) => void;
-  readonly benchDefault: number;
-}) {
-  return (
-    <div className="workbench-settings-pane">
-      <label className="chat-settings-field">
-        <span>{CHAT_STRINGS.workbenchSettingsNameLabel}</span>
-        <Input value={name} onChange={(event) => onNameChange(event.target.value)} />
-      </label>
-      <label className="chat-settings-field">
-        <span>{CHAT_STRINGS.workbenchSettingsPurposeLabel}</span>
-        <textarea
-          className="chat-textarea"
-          value={purpose}
-          onChange={(event) => onPurposeChange(event.target.value)}
-          placeholder={CHAT_STRINGS.workbenchSettingsPurposePlaceholder}
-          rows={2}
-        />
-      </label>
-      <label className="chat-settings-field chat-settings-field-inline">
-        <span>{CHAT_STRINGS.workbenchSettingsPinnedLabel}</span>
-        <Switch
-          checked={pinned}
-          onCheckedChange={onPinnedChange}
-          label={CHAT_STRINGS.workbenchSettingsPinnedLabel}
-        />
-      </label>
-      <p className="chat-settings-field-hint">{CHAT_STRINGS.workbenchSettingsPinnedDescription}</p>
-      <div className="chat-settings-field">
-        <span>{CHAT_STRINGS.workbenchSettingsContextWindowLabel}</span>
-        <div
-          className="chat-context-window-control"
-          role="radiogroup"
-          aria-label={CHAT_STRINGS.workbenchSettingsContextWindowLabel}
-        >
-          <label className="chat-context-window-option">
-            <input
-              type="radio"
-              name={`context-window-mode-${workbenchId}`}
-              checked={contextWindowMode === "inherit"}
-              onChange={() => onContextWindowModeChange("inherit")}
-            />
-            {CHAT_STRINGS.workbenchSettingsUseBenchDefault(benchDefault)}
-          </label>
-          <label className="chat-context-window-option">
-            <input
-              type="radio"
-              name={`context-window-mode-${workbenchId}`}
-              checked={contextWindowMode === "override"}
-              onChange={() => onContextWindowModeChange("override")}
-            />
-            {CHAT_STRINGS.workbenchSettingsUseOverride}
-          </label>
-          <Input
-            value={contextWindowInput}
-            disabled={contextWindowMode === "inherit"}
-            inputMode="numeric"
-            onChange={(event) => onContextWindowInputChange(event.target.value)}
-          />
-        </div>
-      </div>
-      <p className="chat-settings-field-hint">
-        {CHAT_STRINGS.workbenchSettingsContextWindowDescription}
-      </p>
-      <div className="chat-settings-callout">
-        <span className="chat-settings-callout-label">
-          {CHAT_STRINGS.workbenchSettingsDeliveryTitle}
-        </span>
-        <p>{CHAT_STRINGS.workbenchSettingsDeliveryBody}</p>
-      </div>
-    </div>
-  );
-}
diff --git a/apps/web/src/chat/workbench-settings/index.ts b/apps/web/src/chat/workbench-settings/index.ts
deleted file mode 100644
index 08833f567..000000000
--- a/apps/web/src/chat/workbench-settings/index.ts
+++ /dev/null
@@ -1,13 +0,0 @@
-export { WorkbenchSettingsSurface } from "./surface";
-export { contextWindowControlState, contextWindowPatchValue } from "./context-window";
-export type { ContextWindowMode } from "./context-window";
-export {
-  workbenchSettingsSections,
-  isWorkbenchSettingsSectionId,
-  WORKBENCH_SETTINGS_SECTION_IDS,
-} from "./model";
-export type {
-  WorkbenchSettingsSection,
-  WorkbenchSettingsSectionGroup,
-  WorkbenchSettingsSectionId,
-} from "./model";
diff --git a/apps/web/src/chat/workbench-settings/members-section.tsx b/apps/web/src/chat/workbench-settings/members-section.tsx
deleted file mode 100644
index 77fa3c5c7..000000000
--- a/apps/web/src/chat/workbench-settings/members-section.tsx
+++ /dev/null
@@ -1,95 +0,0 @@
-// Members section: the human participants split out from agents (see
-// AgentsSection). Each row carries a Remove affordance: a
-// second-click `ConfirmButton` that drops the member's participant
-// record server-side (`removeWorkbenchParticipant`), disabled for the
-// signed-in viewer's own row — there is no "leave" flow yet, so removing
-// yourself here would strand you outside a workbench you can't rejoin.
-
-import { useState } from "react";
-import { ConfirmButton } from "@corbits/react-ui";
-import { isAgentAddress } from "../wire/mentions";
-
-import type { ParticipantRecord } from "../api";
-import { describeChatError, removeWorkbenchParticipant } from "../api";
-import { CHAT_STRINGS } from "../strings";
-
-export function MembersSection({
-  tenantId,
-  workbenchId,
-  participants,
-  currentUserPrincipalId,
-  onParticipantsChanged,
-}: {
-  readonly tenantId: string;
-  readonly workbenchId: string;
-  readonly participants: readonly ParticipantRecord[];
-  /** The signed-in viewer's own principal id, so their own row's Remove
-   * button can be disabled — omitted, no row is treated as "you". */
-  readonly currentUserPrincipalId?: string;
-  /** Fired after a successful removal so the host can refetch the
-   * workbench's participants — this section never trusts an optimistic
-   * local edit for who still belongs to the workbench. */
-  readonly onParticipantsChanged: () => void;
-}) {
-  const [removingAddress, setRemovingAddress] = useState<string | null>(null);
-  const [rowError, setRowError] = useState<string | null>(null);
-  const people = participants.filter((p) => !isAgentAddress(p.address));
-
-  function handleRemove(address: string) {
-    setRemovingAddress(address);
-    setRowError(null);
-    removeWorkbenchParticipant(tenantId, workbenchId, address)
-      .then(() => onParticipantsChanged())
-      .catch((cause: unknown) =>
-        setRowError(describeChatError(cause, CHAT_STRINGS.workbenchSettingsRemoveError)),
-      )
-      .finally(() => setRemovingAddress(null));
-  }
-
-  return (
-    <div className="workbench-settings-pane">
-      <div className="chat-settings-field">
-        <span>{CHAT_STRINGS.workbenchSettingsPeopleLabel}</span>
-        {people.length === 0 ? (
-          <p className="chat-settings-field-hint">{CHAT_STRINGS.workbenchSettingsNoPeople}</p>
-        ) : (
-          <ul className="chat-settings-participants-list">
-            {people.map((participant) => {
-              const isSelf = participant.address === currentUserPrincipalId;
-              const busy = removingAddress === participant.address;
-              return (
-                <li key={participant.address} className="chat-settings-participant-row">
-                  <div className="chat-settings-participant-row-main">
-                    <span>{participant.handle}</span>
-                    <ConfirmButton
-                      variant="outline"
-                      size="sm"
-                      confirmLabel={CHAT_STRINGS.workbenchSettingsRemoveConfirmLabel}
-                      disabled={isSelf || busy}
-                      title={isSelf ? CHAT_STRINGS.workbenchSettingsRemoveSelfHint : undefined}
-                      onConfirm={() => handleRemove(participant.address)}
-                    >
-                      {busy
-                        ? CHAT_STRINGS.workbenchSettingsRemoving
-                        : CHAT_STRINGS.workbenchSettingsRemoveAction}
-                    </ConfirmButton>
-                  </div>
-                  <p className="chat-settings-field-hint">
-                    {isSelf
-                      ? CHAT_STRINGS.workbenchSettingsRemoveSelfHint
-                      : CHAT_STRINGS.workbenchSettingsRemoveConsequence}
-                  </p>
-                </li>
-              );
-            })}
-          </ul>
-        )}
-        {rowError !== null ? (
-          <p className="chat-dialog-error" role="alert">
-            {rowError}
-          </p>
-        ) : null}
-      </div>
-    </div>
-  );
-}
diff --git a/apps/web/src/chat/workbench-settings/model.test.ts b/apps/web/src/chat/workbench-settings/model.test.ts
deleted file mode 100644
index f7f08677c..000000000
--- a/apps/web/src/chat/workbench-settings/model.test.ts
+++ /dev/null
@@ -1,90 +0,0 @@
-import { describe, expect, test } from "bun:test";
-
-import {
-  isWorkbenchSettingsSectionId,
-  workbenchSettingsSections,
-  WORKBENCH_SETTINGS_SECTION_IDS,
-} from "./model";
-
-describe("isWorkbenchSettingsSectionId", () => {
-  test("is true for exactly the known section ids", () => {
-    for (const id of WORKBENCH_SETTINGS_SECTION_IDS) {
-      expect(isWorkbenchSettingsSectionId(id)).toBe(true);
-    }
-  });
-
-  test("is false for a value that isn't a section id", () => {
-    expect(isWorkbenchSettingsSectionId("not-a-real-section")).toBe(false);
-    expect(isWorkbenchSettingsSectionId("")).toBe(false);
-  });
-});
-
-describe("workbenchSettingsSections", () => {
-  test("workbenches expose the full settings surface: General/Agents in Shared, Notifications in Personal", () => {
-    expect(workbenchSettingsSections("workbench").map((s) => s.id)).toEqual([
-      "general",
-      "members",
-      "agents",
-      "notifications",
-      "danger",
-    ]);
-  });
-
-  test("1:1 chats trim Members and Danger zone", () => {
-    expect(workbenchSettingsSections("chat").map((s) => s.id)).toEqual([
-      "general",
-      "agents",
-      "notifications",
-    ]);
-  });
-
-  test("a DM chat additionally trims Agents — no agent participant, nothing to invite", () => {
-    expect(workbenchSettingsSections("chat", true).map((s) => s.id)).toEqual([
-      "general",
-      "notifications",
-    ]);
-  });
-
-  test("an agent chat keeps Agents when isDm is explicitly false", () => {
-    expect(workbenchSettingsSections("chat", false).map((s) => s.id)).toEqual([
-      "general",
-      "agents",
-      "notifications",
-    ]);
-  });
-
-  test("isDm is ignored for a workbench — Agents stays regardless", () => {
-    expect(workbenchSettingsSections("workbench", true).map((s) => s.id)).toEqual([
-      "general",
-      "members",
-      "agents",
-      "notifications",
-      "danger",
-    ]);
-  });
-
-  test("Myra/Keys & tools/Inference are gone as distinct nav ids", () => {
-    const ids = workbenchSettingsSections("workbench").map((s) => s.id);
-    expect(ids).not.toContain("assistant");
-    expect(ids).not.toContain("keys-tools");
-    expect(ids).not.toContain("inference");
-  });
-
-  test("Tools is global-only now — no workbench-scoped nav id", () => {
-    expect(workbenchSettingsSections("workbench").map((s) => s.id)).not.toContain("tools");
-    expect(workbenchSettingsSections("chat", true).map((s) => s.id)).not.toContain("tools");
-  });
-
-  test("Capacity is gone — sidecar placement is Interchange's own concern now", () => {
-    expect(workbenchSettingsSections("chat").map((s) => s.id)).not.toContain("capacity");
-    expect(workbenchSettingsSections("workbench").map((s) => s.id)).not.toContain("capacity");
-    expect(WORKBENCH_SETTINGS_SECTION_IDS).not.toContain(
-      "capacity" as (typeof WORKBENCH_SETTINGS_SECTION_IDS)[number],
-    );
-  });
-
-  test("groups sections Shared / Personal / Danger for the nav", () => {
-    const groups = workbenchSettingsSections("workbench").map((s) => s.group);
-    expect(groups).toEqual(["shared", "shared", "shared", "personal", "danger"]);
-  });
-});
diff --git a/apps/web/src/chat/workbench-settings/model.ts b/apps/web/src/chat/workbench-settings/model.ts
deleted file mode 100644
index acd4d6dc3..000000000
--- a/apps/web/src/chat/workbench-settings/model.ts
+++ /dev/null
@@ -1,104 +0,0 @@
-// The settings surface's own section registry. Workbenches are tenants — their
-// settings are a full stage surface (mock § Workbench settings), grouped
-// Shared / Personal / Danger zone, never a dialog with tabs.
-//
-// Agents is now the one place an agent participant's persona,
-// capabilities, and history are edited — a click-through master-detail,
-// not a separate "Myra" nav item duplicating the same editor for one
-// hardcoded agent. Keys & tools and Inference are gone as distinct
-// sections: inference provider+model assignment moves onto the Agents
-// detail view, per agent, fed from the tenant-wide provider pool.
-//
-// Tools are global-only for now (owner ruling): the workbench-scoped
-// `tools` section that used to live here is removed — connect/manage
-// tools from the bench-level Tools page instead. Per-workbench
-// credential rows written by that old section are left in place (nothing
-// reads or writes them now); see the Tools page for the surviving
-// surface.
-
-import { CHAT_STRINGS } from "../strings";
-
-export type WorkbenchSettingsSectionId =
-  | "general"
-  | "members"
-  | "agents"
-  | "notifications"
-  | "danger";
-
-/** Every `WorkbenchSettingsSectionId`, for validating a section id read
- * off a URL — a route parser needs this list to narrow untrusted input
- * without an unchecked cast; `sectionsForWorkbenchKind` below is a
- * per-kind subset that doesn't fit that job. */
-export const WORKBENCH_SETTINGS_SECTION_IDS: readonly WorkbenchSettingsSectionId[] = [
-  "general",
-  "members",
-  "agents",
-  "notifications",
-  "danger",
-];
-
-export function isWorkbenchSettingsSectionId(value: string): value is WorkbenchSettingsSectionId {
-  return (WORKBENCH_SETTINGS_SECTION_IDS as readonly string[]).includes(value);
-}
-
-export type WorkbenchSettingsSectionGroup = "shared" | "personal" | "danger";
-
-export type WorkbenchSettingsSection = {
-  readonly id: WorkbenchSettingsSectionId;
-  readonly label: string;
-  readonly group: WorkbenchSettingsSectionGroup;
-};
-
-/**
- * Sections available for a workbench kind, in nav order. 1:1 chats drop
- * Members and Danger zone so the surface stays short (owner decision /
- * mock) — the same trim `workbenchSettingsTabs` applied before this file's
- * restructure.
- *
- * `isDm` additionally trims Agents: a DM (owner decision — "a DM = a
- * two-member workbench tenancy with a trimmed settings surface") has no
- * agent participant and no agent to ever invite (its counterpart is
- * fixed at creation, exactly like an agent chat's is), so the section
- * — and the invite-agent affordance it renders — has nothing to show.
- * Defaults to `false` so every existing call site (agent chats,
- * workbenches) keeps exactly the section list it already had.
- */
-export function workbenchSettingsSections(
-  workbenchKind: string,
-  isDm = false,
-): readonly WorkbenchSettingsSection[] {
-  const sections: WorkbenchSettingsSection[] = [
-    {
-      id: "general",
-      label: CHAT_STRINGS.workbenchSettingsSectionGeneral,
-      group: "shared",
-    },
-  ];
-  if (workbenchKind !== "chat") {
-    sections.push({
-      id: "members",
-      label: CHAT_STRINGS.workbenchSettingsSectionMembers,
-      group: "shared",
-    });
-  }
-  if (!(workbenchKind === "chat" && isDm)) {
-    sections.push({
-      id: "agents",
-      label: CHAT_STRINGS.workbenchSettingsSectionAgents,
-      group: "shared",
-    });
-  }
-  sections.push({
-    id: "notifications",
-    label: CHAT_STRINGS.workbenchSettingsSectionNotifications,
-    group: "personal",
-  });
-  if (workbenchKind !== "chat") {
-    sections.push({
-      id: "danger",
-      label: CHAT_STRINGS.workbenchSettingsSectionDanger,
-      group: "danger",
-    });
-  }
-  return sections;
-}
diff --git a/apps/web/src/chat/workbench-settings/surface.tsx b/apps/web/src/chat/workbench-settings/surface.tsx
deleted file mode 100644
index 5ae5dbedf..000000000
--- a/apps/web/src/chat/workbench-settings/surface.tsx
+++ /dev/null
@@ -1,316 +0,0 @@
-// Workbench settings as a full stage surface (mock § Workbench settings):
-// workbenches are tenants, so their settings replace the whole stage — a
-// breadcrumb back to the workbench, a left nav grouped Shared / Personal /
-// Danger zone, and the active section's panel on the right. Never a dialog.
-//
-// Save still PATCHes name, purpose, pin, and context window (the General
-// section's fields); the other sections' field gaps (who-can-post,
-// retention, role selects, per-workbench grants) are separate tickets — this
-// only re-houses what the panel already rendered.
-
-import { Button, toast } from "@corbits/react-ui";
-import { isAgentAddress } from "../wire/mentions";
-import { useEffect, useState } from "react";
-
-import type { APIQuery } from "@/lib/api-query";
-import { QueryView, UnauthenticatedError, describeQueryError } from "@/lib/api-query";
-import { getBenchChatSettings, getWorkbenchSettings, patchWorkbenchSettings } from "../api";
-import type { WorkbenchSettings } from "../api";
-import { WorkbenchLoadingState } from "../loading-state";
-import { CHAT_STRINGS } from "../strings";
-import { AgentsSection } from "./agents-section";
-import { contextWindowControlState, contextWindowPatchValue } from "./context-window";
-import type { ContextWindowMode } from "./context-window";
-import { DangerSection } from "./danger-section";
-import { GeneralSection } from "./general-section";
-import { MembersSection } from "./members-section";
-import { workbenchSettingsSections } from "./model";
-import type { WorkbenchSettingsSection, WorkbenchSettingsSectionId } from "./model";
-
-type WorkbenchSettingsData = {
-  readonly data: WorkbenchSettings;
-  readonly benchDefault: number;
-};
-
-const SECTION_GROUP_ORDER = ["shared", "personal", "danger"] as const;
-
-function groupLabel(group: (typeof SECTION_GROUP_ORDER)[number]): string {
-  switch (group) {
-    case "shared":
-      return CHAT_STRINGS.workbenchSettingsGroupShared;
-    case "personal":
-      return CHAT_STRINGS.workbenchSettingsGroupPersonal;
-    case "danger":
-      return "";
-  }
-}
-
-export function WorkbenchSettingsSurface({
-  tenantId,
-  workbenchId,
-  workbenchTitle,
-  onBack,
-  onSaved,
-  section = "general",
-  onSectionChange,
-  currentUserPrincipalId,
-  entityId = null,
-  onEntityIdChange,
-}: {
-  readonly tenantId: string;
-  readonly workbenchId: string;
-  readonly workbenchTitle: string;
-  readonly onBack: () => void;
-  readonly onSaved?: (settings: WorkbenchSettings) => void;
-  /** The signed-in viewer's own principal id — threaded down to
-   * `MembersSection` so their own row's Remove button is disabled.
-   * Omitted, no row is treated as "you". */
-  readonly currentUserPrincipalId?: string;
-  /** Which section is active — host-controlled the same way `settingsOpen`
-   * is on `ChatWorkspace`: `/agents` opens straight to Agents rather than
-   * the default General, and a deep link (`/w/:id/settings/:section`)
-   * lands directly on it. */
-  readonly section?: WorkbenchSettingsSectionId;
-  /** Fired when the user picks a different tab, so the host can reflect it
-   * in the URL. Omitted, tab clicks have no effect — same contract as
-   * `onSettingsOpenChange` being omitted on `ChatWorkspace`. */
-  readonly onSectionChange?: (section: WorkbenchSettingsSectionId) => void;
-  /** Section sub-selection (`/w/:id/settings/:section/:entityId`) —
-   * currently used by Agents for the open definition id. */
-  readonly entityId?: string | null;
-  /** Fired when a section opens or closes its own detail so the host can
-   * deepen or clear the entity segment in the URL. */
-  readonly onEntityIdChange?: (entityId: string | null) => void;
-}) {
-  const [query, setQuery] = useState<APIQuery<WorkbenchSettingsData>>({
-    kind: "loading",
-  });
-  const [name, setName] = useState("");
-  const [purpose, setPurpose] = useState("");
-  const [pinned, setPinned] = useState(false);
-  const [contextWindowMode, setContextWindowMode] = useState<ContextWindowMode>("inherit");
-  const [contextWindowInput, setContextWindowInput] = useState("");
-  const [saving, setSaving] = useState(false);
-  const [saveError, setSaveError] = useState<string | null>(null);
-  const [reloadKey, setReloadKey] = useState(0);
-  const reload = () => setReloadKey((value) => value + 1);
-
-  useEffect(() => {
-    let cancelled = false;
-    setQuery({ kind: "loading" });
-    Promise.all([getWorkbenchSettings(tenantId, workbenchId), getBenchChatSettings(tenantId)])
-      .then(([settings, bench]) => {
-        if (cancelled) return;
-        const control = contextWindowControlState(settings.contextWindow);
-        const storedPurpose = settings.settings["chat/purpose"];
-        setName(settings.title);
-        setPurpose(typeof storedPurpose === "string" ? storedPurpose : "");
-        setPinned(settings.pinned);
-        setContextWindowMode(control.mode);
-        setContextWindowInput(String(control.displayValue));
-        setQuery({
-          kind: "ready",
-          data: {
-            data: settings,
-            benchDefault: bench.contextWindow,
-          },
-        });
-      })
-      .catch((cause: unknown) => {
-        if (cancelled) return;
-        if (cause instanceof UnauthenticatedError) {
-          setQuery({ kind: "unauthenticated" });
-          return;
-        }
-        setQuery({
-          kind: "error",
-          message: describeQueryError(cause),
-          retry: reload,
-        });
-      });
-    return () => {
-      cancelled = true;
-    };
-  }, [tenantId, workbenchId, reloadKey]);
-
-  const ready = query.kind === "ready" ? query.data : undefined;
-
-  // A DM (owner decision: "a DM = a two-member workbench tenancy with a
-  // trimmed settings surface") is a chat carrying no agent-shaped
-  // participant address — the same derivation the host app's sidebar
-  // uses to bucket it (`assignWorkbenchBucket`), so this trims Agents
-  // without a second signal to keep in sync.
-  const hasAgent =
-    ready !== undefined &&
-    ready.data.participants.some((participant) => isAgentAddress(participant.address));
-  const isDm = ready !== undefined && !hasAgent;
-  const sections = workbenchSettingsSections(
-    ready !== undefined ? ready.data.kind : "workbench",
-    isDm,
-  );
-  const firstSection = sections[0];
-  if (firstSection === undefined) {
-    throw new Error("workbenchSettingsSections returned no sections");
-  }
-  const activeSection: WorkbenchSettingsSection =
-    sections.find((s) => s.id === section) ?? firstSection;
-
-  const overrideValue = Number.parseInt(contextWindowInput, 10);
-  const overrideValid =
-    contextWindowMode === "inherit" || (Number.isFinite(overrideValue) && overrideValue >= 0);
-  const saveDisabled = ready === undefined || !overrideValid || saving;
-
-  function handleSave() {
-    if (saveDisabled || ready === undefined) return;
-    setSaving(true);
-    setSaveError(null);
-    patchWorkbenchSettings(tenantId, workbenchId, {
-      "chat/name": name.trim().length > 0 ? name.trim() : ready.data.title,
-      "chat/purpose": purpose,
-      "chat/pinned": pinned,
-      "chat/contextWindow": contextWindowPatchValue(
-        contextWindowMode,
-        Number.isFinite(overrideValue) ? overrideValue : 0,
-      ),
-    })
-      .then((settings) => {
-        toast(CHAT_STRINGS.workbenchSettingsSavedToast);
-        onSaved?.(settings);
-      })
-      .catch(() => setSaveError(CHAT_STRINGS.workbenchSettingsSaveError))
-      .finally(() => setSaving(false));
-  }
-
-  return (
-    <div className="workbench-settings-stage">
-      <div className="workbench-settings-topbar">
-        <div className="workbench-settings-topbar-identity">
-          <nav
-            className="workbench-settings-breadcrumb"
-            aria-label={CHAT_STRINGS.workbenchSettingsBreadcrumbLabel}
-          >
-            <button type="button" onClick={onBack}>
-              {workbenchTitle}
-            </button>
-            <span className="workbench-settings-breadcrumb-sep" aria-hidden="true">
-              /
-            </span>
-            <span className="workbench-settings-breadcrumb-current">
-              {CHAT_STRINGS.workbenchSettingsBreadcrumbCurrent}
-            </span>
-          </nav>
-          <span className="workbench-settings-section-dot" aria-hidden="true" />
-          <span className="workbench-settings-section-label">{activeSection.label}</span>
-        </div>
-        {/* One primary action visible per view where possible: the
-            Agents section has its own scoped "Save
-            instructions" action per agent, so the top-bar Save — which
-            only ever writes the General section's fields — stays hidden
-            rather than sitting alongside a second, unrelated primary. */}
-        {activeSection.id !== "agents" ? (
-          <Button
-            type="button"
-            variant="primary"
-            size="sm"
-            disabled={saveDisabled}
-            onClick={handleSave}
-          >
-            {saving ? CHAT_STRINGS.workbenchSettingsSaving : CHAT_STRINGS.workbenchSettingsSave}
-          </Button>
-        ) : null}
-      </div>
-
-      <QueryView
-        query={query}
-        label={CHAT_STRINGS.workbenchSettingsLoadError}
-        loadingContent={<WorkbenchLoadingState title="Loading workbench settings…" />}
-      >
-        {({ data, benchDefault }) => (
-          <div className="workbench-settings-shell">
-            <nav
-              className="workbench-settings-nav"
-              aria-label={CHAT_STRINGS.workbenchSettingsNavLabel}
-            >
-              {SECTION_GROUP_ORDER.map((group) => {
-                const groupSections = sections.filter((s) => s.group === group);
-                if (groupSections.length === 0) return null;
-                const label = groupLabel(group);
-                return (
-                  <div
-                    key={group}
-                    className={
-                      group === "danger"
-                        ? "workbench-settings-nav-group workbench-settings-nav-group-danger"
-                        : "workbench-settings-nav-group"
-                    }
-                  >
-                    {label !== "" ? (
-                      <div className="workbench-settings-nav-group-label">{label}</div>
-                    ) : null}
-                    {groupSections.map((s) => (
-                      <button
-                        key={s.id}
-                        type="button"
-                        className="workbench-settings-nav-item"
-                        aria-current={s.id === activeSection.id ? "page" : undefined}
-                        onClick={() => onSectionChange?.(s.id)}
-                      >
-                        {s.label}
-                      </button>
-                    ))}
-                  </div>
-                );
-              })}
-            </nav>
-
-            <div className="workbench-settings-panel-area">
-              {saveError !== null ? (
-                <p className="chat-dialog-error" role="alert">
-                  {saveError}
-                </p>
-              ) : null}
-
-              {activeSection.id === "general" ? (
-                <GeneralSection
-                  workbenchId={workbenchId}
-                  name={name}
-                  onNameChange={setName}
-                  purpose={purpose}
-                  onPurposeChange={setPurpose}
-                  pinned={pinned}
-                  onPinnedChange={setPinned}
-                  contextWindowMode={contextWindowMode}
-                  onContextWindowModeChange={setContextWindowMode}
-                  contextWindowInput={contextWindowInput}
-                  onContextWindowInputChange={setContextWindowInput}
-                  benchDefault={benchDefault}
-                />
-              ) : null}
-
-              {activeSection.id === "members" ? (
-                <MembersSection
-                  tenantId={tenantId}
-                  workbenchId={workbenchId}
-                  participants={data.participants}
-                  {...(currentUserPrincipalId !== undefined ? { currentUserPrincipalId } : {})}
-                  onParticipantsChanged={reload}
-                />
-              ) : null}
-
-              {activeSection.id === "agents" ? (
-                <AgentsSection
-                  tenantId={tenantId}
-                  workbenchId={workbenchId}
-                  entityId={entityId}
-                  {...(onEntityIdChange !== undefined ? { onEntityIdChange } : {})}
-                />
-              ) : null}
-
-              {activeSection.id === "danger" ? <DangerSection /> : null}
-            </div>
-          </div>
-        )}
-      </QueryView>
-    </div>
-  );
-}
diff --git a/apps/web/src/chat/workbench-tenants.ts b/apps/web/src/chat/workbench-tenants.ts
new file mode 100644
index 000000000..02d7456d3
--- /dev/null
+++ b/apps/web/src/chat/workbench-tenants.ts
@@ -0,0 +1,60 @@
+// A workbench is a child tenant, so listing workbenches is listing the
+// bench's children over the stock tenant routes. This is the whole
+// workbench-listing surface the rest of the app reads — the room itself
+// lives in the child tenant's mailbox (`threads-api.ts`).
+
+import { createFetchStockHub, findOwnedTenants } from "../needs-converge";
+import { listChats } from "./threads-api";
+
+export type WorkbenchKind = "workbench" | "chat";
+
+export type Workbench = {
+  readonly id: string;
+  readonly title: string;
+  readonly kind: WorkbenchKind;
+  readonly slug: string;
+  /** A workbench IS its tenant, so every row links to itself. */
+  readonly tenancy?: { readonly tenantId: string } | null;
+  readonly lastActivityAt?: string;
+};
+
+/** Shared by every workbench-listing surface so one create invalidates
+ * them all. */
+export function workbenchesQueryKeyPrefix(tenantId: string): readonly unknown[] {
+  return ["tenant", tenantId, "workbenches"];
+}
+
+export function workbenchesQueryKey(tenantId: string, kind: WorkbenchKind): readonly unknown[] {
+  return [...workbenchesQueryKeyPrefix(tenantId), kind];
+}
+
+export async function listWorkbenchTenants(tenantId: string): Promise<readonly Workbench[]> {
+  const tenants = await findOwnedTenants(createFetchStockHub());
+  return tenants
+    .filter((tenant) => tenant.parentId === tenantId)
+    .map((tenant) => ({
+      id: tenant.id,
+      title: tenant.name,
+      kind: "workbench" as const,
+      slug: tenant.slug,
+      tenancy: { tenantId: tenant.id },
+    }));
+}
+
+/** The two listing surfaces behind one call: workbenches are the bench's
+ * child tenants, chats are the person's own mail threads. */
+export async function listWorkbenches(
+  tenantId: string,
+  kind: WorkbenchKind,
+): Promise<readonly Workbench[]> {
+  if (kind === "workbench") return listWorkbenchTenants(tenantId);
+  const chats = await listChats(tenantId);
+  return chats.map((chat) => ({
+    id: chat.id,
+    title: chat.title,
+    kind: "chat" as const,
+    slug: chat.id,
+    tenancy: { tenantId },
+    lastActivityAt: chat.lastActivityAt,
+  }));
+}
diff --git a/apps/web/src/chat/workbench-timeline-view.ts b/apps/web/src/chat/workbench-timeline-view.ts
deleted file mode 100644
index 0e7894505..000000000
--- a/apps/web/src/chat/workbench-timeline-view.ts
+++ /dev/null
@@ -1,108 +0,0 @@
-// What the timeline shows: the feed's loaded mailbox, sliced by wherever
-// thread navigation has the reader standing.
-//
-// The two halves are deliberately separate — `use-workbench-feed` loads a
-// workbench's mailbox without knowing which thread is open, and
-// `use-thread-navigation` tracks which thread is open without knowing what
-// has loaded — so this is the one place that joins them. Keeping the join
-// here is also what stops the two hooks depending on each other.
-
-import { useEffect, useMemo } from "react";
-import { reportError } from "@corbits/error-sink";
-import { useQueryClient } from "@tanstack/react-query";
-import { putReadState, workbenchesQueryKeyPrefix } from "./api";
-import type { MessageItem } from "./api";
-import { selectThreadFeed, threadAffordanceMeta } from "./thread-feed";
-import type { ThreadAffordanceMeta } from "./timeline";
-import type { FeedStatus, WorkbenchFeed } from "./use-workbench-feed";
-import type { ThreadNavigation } from "./use-thread-navigation";
-
-/** What the timeline renders, as a state the view can switch on. */
-export type MessagesState =
-  | { readonly kind: "loading" }
-  | {
-      readonly kind: "error";
-      readonly message: string;
-      /** The workbench itself 404s, not just this load — retrying with the
-       * same id can never succeed, so the UI trades "Try again" for an
-       * honest way out instead. */
-      readonly workbenchNotFound: boolean;
-      /** A 401 means the session itself is gone — "Try again" would hit
-       * the same 401 forever, so the UI offers a way to sign back in
-       * instead of a retry that can never succeed. */
-      readonly isUnauthorized: boolean;
-    }
-  | { readonly kind: "ready"; readonly items: readonly MessageItem[] };
-
-export function messagesStateFor(status: FeedStatus, items: readonly MessageItem[]): MessagesState {
-  return status.kind === "ready" ? { kind: "ready", items } : status;
-}
-
-export interface WorkbenchTimelineView {
-  readonly messagesState: MessagesState;
-  readonly threadMetaByMessageId: ReadonlyMap<string, ThreadAffordanceMeta>;
-}
-
-export function useWorkbenchTimelineView(args: {
-  readonly tenantId: string;
-  readonly activeWorkbenchId: string | null;
-  readonly feed: WorkbenchFeed;
-  readonly navigation: ThreadNavigation;
-}): WorkbenchTimelineView {
-  const { tenantId, activeWorkbenchId, feed, navigation } = args;
-  const queryClient = useQueryClient();
-  const { loadedMessages, rootThreadId, threads, feedStatus } = feed;
-  const { openThreadId, openThread, pendingParentMessageId } = navigation;
-
-  // The parent a thread hangs off comes from the thread itself once it
-  // exists, and from the message the reader is replying to before it
-  // does — one value either way, so the feed never has to know which case
-  // it is in.
-  const parentMessageId = openThread?.parentMessageId ?? pendingParentMessageId ?? null;
-
-  const feedItems = useMemo(
-    () =>
-      selectThreadFeed(loadedMessages, {
-        openThreadId,
-        parentMessageId,
-        rootThreadId,
-      }),
-    [loadedMessages, openThreadId, parentMessageId, rootThreadId],
-  );
-
-  const threadMetaByMessageId = useMemo(
-    () => threadAffordanceMeta(threads, loadedMessages),
-    [threads, loadedMessages],
-  );
-
-  // Marking read follows the root feed only: a reader inside a thread
-  // hasn't seen the main timeline, so advancing the cursor there would
-  // clear an unread badge for messages they never looked at.
-  useEffect(() => {
-    if (activeWorkbenchId === null) return;
-    if (openThreadId !== null || pendingParentMessageId !== null) return;
-    const last = feedItems.at(-1);
-    if (last === undefined) return;
-    void putReadState(tenantId, activeWorkbenchId, {
-      lastSeenCreatedAt: last.createdAt,
-      lastSeenId: last.id,
-    })
-      .then(() =>
-        queryClient.invalidateQueries({
-          queryKey: workbenchesQueryKeyPrefix(tenantId),
-        }),
-      )
-      .catch((error: unknown) => {
-        reportError(error, {
-          operation: "chat.markRead",
-          tenantId,
-          roomId: activeWorkbenchId,
-        });
-      });
-  }, [tenantId, activeWorkbenchId, openThreadId, pendingParentMessageId, feedItems, queryClient]);
-
-  return {
-    messagesState: messagesStateFor(feedStatus, feedItems),
-    threadMetaByMessageId,
-  };
-}
diff --git a/apps/web/src/chat/workbenches-mutated-event.test.ts b/apps/web/src/chat/workbenches-mutated-event.test.ts
deleted file mode 100644
index 3f604d9f3..000000000
--- a/apps/web/src/chat/workbenches-mutated-event.test.ts
+++ /dev/null
@@ -1,115 +0,0 @@
-import { afterEach, describe, expect, test } from "bun:test";
-
-import { GlobalRegistrator } from "@happy-dom/global-registrator";
-import { WORKBENCHES_MUTATED_EVENT, applyStreamWorkbenchesMutated, createWorkbench } from "./api";
-
-if (typeof document === "undefined") {
-  GlobalRegistrator.register();
-}
-
-const realFetch = globalThis.fetch;
-afterEach(() => {
-  globalThis.fetch = realFetch;
-});
-
-const workbench = {
-  id: "chat-1",
-  kind: "chat",
-  title: "Myra",
-  participants: [],
-  pinned: false,
-};
-
-describe("createWorkbench mutation event", () => {
-  test("a successful create dispatches WORKBENCHES_MUTATED_EVENT with the tenant id", async () => {
-    globalThis.fetch = (() =>
-      Promise.resolve(
-        new Response(JSON.stringify(workbench), {
-          status: 200,
-          headers: { "content-type": "application/json" },
-        }),
-      )) as unknown as typeof fetch;
-    const seen: string[] = [];
-    const listener = (event: Event) => {
-      seen.push((event as CustomEvent<{ tenantId: string }>).detail.tenantId);
-    };
-    window.addEventListener(WORKBENCHES_MUTATED_EVENT, listener);
-    try {
-      await createWorkbench("tnt_1", { kind: "chat", definitionId: "def_1" });
-    } finally {
-      window.removeEventListener(WORKBENCHES_MUTATED_EVENT, listener);
-    }
-    expect(seen).toEqual(["tnt_1"]);
-  });
-
-  test("a failed create dispatches nothing", async () => {
-    globalThis.fetch = (() =>
-      Promise.resolve(
-        new Response(JSON.stringify({ error: { message: "nope" } }), {
-          status: 422,
-          headers: { "content-type": "application/json" },
-        }),
-      )) as unknown as typeof fetch;
-    let fired = 0;
-    const listener = () => {
-      fired += 1;
-    };
-    window.addEventListener(WORKBENCHES_MUTATED_EVENT, listener);
-    try {
-      await expect(
-        createWorkbench("tnt_1", { kind: "chat", definitionId: "def_1" }),
-      ).rejects.toThrow();
-    } finally {
-      window.removeEventListener(WORKBENCHES_MUTATED_EVENT, listener);
-    }
-    expect(fired).toBe(0);
-  });
-});
-
-describe("applyStreamWorkbenchesMutated", () => {
-  test("valid { tenantId } dispatches WORKBENCHES_MUTATED_EVENT with that tenantId", () => {
-    const seen: string[] = [];
-    const listener = (event: Event) => {
-      seen.push((event as CustomEvent<{ tenantId: string }>).detail.tenantId);
-    };
-    window.addEventListener(WORKBENCHES_MUTATED_EVENT, listener);
-    try {
-      applyStreamWorkbenchesMutated({ tenantId: "tnt_1" });
-    } finally {
-      window.removeEventListener(WORKBENCHES_MUTATED_EVENT, listener);
-    }
-    expect(seen).toEqual(["tnt_1"]);
-  });
-
-  test("garbage / missing tenantId does not dispatch", () => {
-    let fired = 0;
-    const listener = () => {
-      fired += 1;
-    };
-    window.addEventListener(WORKBENCHES_MUTATED_EVENT, listener);
-    try {
-      applyStreamWorkbenchesMutated(undefined);
-      applyStreamWorkbenchesMutated(null);
-      applyStreamWorkbenchesMutated({});
-      applyStreamWorkbenchesMutated({ tenantId: 1 });
-      applyStreamWorkbenchesMutated("tnt_1");
-    } finally {
-      window.removeEventListener(WORKBENCHES_MUTATED_EVENT, listener);
-    }
-    expect(fired).toBe(0);
-  });
-
-  test("extra keys in data still dispatch (forward-compatible)", () => {
-    const seen: string[] = [];
-    const listener = (event: Event) => {
-      seen.push((event as CustomEvent<{ tenantId: string }>).detail.tenantId);
-    };
-    window.addEventListener(WORKBENCHES_MUTATED_EVENT, listener);
-    try {
-      applyStreamWorkbenchesMutated({ tenantId: "tnt_1", extra: "ok" });
-    } finally {
-      window.removeEventListener(WORKBENCHES_MUTATED_EVENT, listener);
-    }
-    expect(seen).toEqual(["tnt_1"]);
-  });
-});
diff --git a/apps/web/src/command-palette-actions.test.ts b/apps/web/src/command-palette-actions.test.ts
index d0a105e43..2f3734bd8 100644
--- a/apps/web/src/command-palette-actions.test.ts
+++ b/apps/web/src/command-palette-actions.test.ts
@@ -142,66 +142,4 @@ describe("runActionCommand", () => {
     await runActionCommand("go-insights", ctx);
     expect(navigated).toEqual(["/insights"]);
   });
-
-  test("talk-to-myra does nothing without a selected bench", async () => {
-    const { ctx, navigated } = context({ path: "/", tenantId: null });
-    await runActionCommand("talk-to-myra", ctx);
-    expect(navigated).toEqual([]);
-  });
-
-  test("talk-to-myra opens Myra's DM via kind=chat + definitionId, not a title-match mint", async () => {
-    const calls: { readonly path: string; readonly init?: RequestInit }[] = [];
-    globalThis.fetch = ((input: RequestInfo | URL, init?: RequestInit) => {
-      const path = typeof input === "string" ? input : new URL(String(input)).pathname;
-      calls.push(init === undefined ? { path } : { path, init });
-      if (path.includes("/workflows/definitions")) {
-        return Promise.resolve(
-          new Response(
-            JSON.stringify({
-              data: [
-                {
-                  id: "wfd_assistant",
-                  tenantId: "tenant-1",
-                  name: "assistant",
-                  currentVersion: "1",
-                  status: "deployed",
-                  createdAt: "2026-01-01T00:00:00.000Z",
-                  updatedAt: "2026-01-01T00:00:00.000Z",
-                },
-              ],
-              nextCursor: null,
-            }),
-            { status: 200, headers: { "content-type": "application/json" } },
-          ),
-        );
-      }
-      if (path.endsWith("/chat/workbenches")) {
-        return Promise.resolve(
-          new Response(
-            JSON.stringify({
-              id: "chan_myra_dm",
-              title: "Myra",
-              kind: "chat",
-              pinned: false,
-              participants: [],
-            }),
-            { status: 200, headers: { "content-type": "application/json" } },
-          ),
-        );
-      }
-      throw new Error(`unexpected fetch: ${init?.method ?? "GET"} ${path}`);
-    }) as typeof fetch;
-
-    const { ctx, navigated } = context({ path: "/" });
-    await runActionCommand("talk-to-myra", ctx);
-
-    const createCall = calls.find((call) => call.path.endsWith("/chat/workbenches"));
-    expect(createCall?.init?.method).toBe("POST");
-    expect(JSON.parse(String(createCall?.init?.body))).toEqual({
-      kind: "chat",
-      definitionId: "wfd_assistant",
-      reuseExisting: true,
-    });
-    expect(navigated).toEqual(["/w/chan_myra_dm"]);
-  });
 });
diff --git a/apps/web/src/command-palette-actions.ts b/apps/web/src/command-palette-actions.ts
index fe43d87ca..8b627d1c1 100644
--- a/apps/web/src/command-palette-actions.ts
+++ b/apps/web/src/command-palette-actions.ts
@@ -22,9 +22,7 @@ import { createPendingDialogRequest } from "@/shell/layout";
 import { CHAT_STRINGS } from "@/chat";
 import { WORKBENCH_PATH_PREFIX } from "./workbench-path";
 import { NEW_WORKBENCH_PATH } from "./routes";
-import { listAgentDefinitions } from "./agents-api";
-import { openAgentDmChat } from "./agent-dm-launch";
-import { findMyraDefinition } from "./myra-workbench";
+import { NEW_CHAT_PATH } from "./chat-path";
 import { requestLibraryUpload } from "./library-upload";
 
 export const NEW_SKILL_EVENT = "workbench:skills:create";
@@ -142,10 +140,8 @@ export async function runActionCommand(
       return;
     }
     case "talk-to-myra": {
-      if (ctx.tenantId === null) return;
-      const myra = findMyraDefinition(await listAgentDefinitions(ctx.tenantId));
-      if (myra === undefined) return;
-      await openAgentDmChat(ctx.tenantId, myra.id, ctx.navigate);
+      // A chat with Myra is a mail thread now, composed on /chats/new.
+      ctx.navigate(NEW_CHAT_PATH);
       return;
     }
     case "go-workbenches": {
diff --git a/apps/web/src/command-palette-provider.tsx b/apps/web/src/command-palette-provider.tsx
index 3b85daa64..e74631fc2 100644
--- a/apps/web/src/command-palette-provider.tsx
+++ b/apps/web/src/command-palette-provider.tsx
@@ -1,6 +1,6 @@
 import { artifactKindLabel, CommandPalette, useCommandShortcut, useTheme } from "@corbits/react-ui";
 import type { CommandPaletteGroup } from "@corbits/react-ui";
-import { listWorkbenches } from "@/chat";
+import { listWorkbenches } from "@/chat/workbench-tenants";
 import { libraryArtifactPath } from "@/library";
 import { reportError } from "@corbits/error-sink";
 import {
diff --git a/apps/web/src/instant-agent-create.test.ts b/apps/web/src/instant-agent-create.test.ts
deleted file mode 100644
index 6f141393f..000000000
--- a/apps/web/src/instant-agent-create.test.ts
+++ /dev/null
@@ -1,202 +0,0 @@
-import { afterEach, describe, expect, test } from "bun:test";
-import { QueryClient } from "@tanstack/react-query";
-
-import {
-  createWorkbench,
-  NEW_WORKBENCH_TITLE,
-  WorkbenchPostCreateError,
-  WorkbenchPreconditionError,
-} from "./instant-agent-create";
-
-function newQueryClient(): QueryClient {
-  return new QueryClient({
-    defaultOptions: { queries: { retry: false } },
-  });
-}
-
-describe("createWorkbench", () => {
-  const realFetch = globalThis.fetch;
-
-  afterEach(() => {
-    globalThis.fetch = realFetch;
-  });
-
-  type RecordedCall = { readonly path: string; readonly init?: RequestInit };
-
-  function stubFetch(respond: (path: string) => Response): RecordedCall[] {
-    const calls: RecordedCall[] = [];
-    globalThis.fetch = ((input: RequestInfo | URL, init?: RequestInit) => {
-      const path = typeof input === "string" ? input : new URL(String(input)).pathname;
-      calls.push(init === undefined ? { path } : { path, init });
-      return Promise.resolve(respond(path));
-    }) as typeof fetch;
-    return calls;
-  }
-
-  const json = (body: unknown, status = 200) =>
-    new Response(JSON.stringify(body), {
-      status,
-      headers: { "content-type": "application/json" },
-    });
-
-  const assistantDefinitionWire = {
-    id: "def-assistant",
-    tenantId: "tnt_1",
-    name: "assistant",
-    currentVersion: "1",
-    status: "deployed",
-    createdAt: "2026-01-01T00:00:00.000Z",
-    updatedAt: "2026-01-01T00:00:00.000Z",
-    skills: [] as readonly string[],
-  };
-
-  test("mints two distinct workbenches on two calls, never reusing one", async () => {
-    let nextId = 0;
-    const navigated: string[] = [];
-    const calls = stubFetch((path) => {
-      if (path.includes("/workflows/definitions")) {
-        return json({ data: [assistantDefinitionWire], nextCursor: null });
-      }
-      if (path.endsWith("/chat/workbenches")) {
-        nextId += 1;
-        return json({
-          id: `chan-${nextId}`,
-          title: NEW_WORKBENCH_TITLE,
-          kind: "workbench",
-          pinned: false,
-          participants: [],
-        });
-      }
-      throw new Error(`unexpected fetch: ${path}`);
-    });
-
-    await createWorkbench("tnt_1", (to) => navigated.push(to), newQueryClient());
-    await createWorkbench("tnt_1", (to) => navigated.push(to), newQueryClient());
-
-    const createCalls = calls.filter((call) => call.path.endsWith("/chat/workbenches"));
-    expect(createCalls).toHaveLength(2);
-    expect(navigated).toEqual(["/w/chan-1", "/w/chan-2"]);
-    expect(navigated[0]).not.toBe(navigated[1]);
-    const body = JSON.parse(String(createCalls[0]?.init?.body));
-    expect(body.name).toBe(NEW_WORKBENCH_TITLE);
-    expect(body.kind).toBe("workbench");
-    expect(body.definitionId).toBeUndefined();
-  });
-
-  test("fails with WorkbenchPreconditionError when Myra isn't deployed yet", async () => {
-    stubFetch((path) => {
-      if (path.includes("/workflows/definitions")) {
-        return json({ data: [], nextCursor: null });
-      }
-      throw new Error(`unexpected fetch: ${path}`);
-    });
-
-    let cause: unknown;
-    try {
-      await createWorkbench("tnt_1", () => undefined, newQueryClient());
-    } catch (error) {
-      cause = error;
-    }
-    expect(cause).toBeInstanceOf(WorkbenchPreconditionError);
-    expect((cause as WorkbenchPreconditionError).kind).toBe("setup-agent-missing");
-  });
-
-  test("a first message renames the room off New Workbench via chat/name", async () => {
-    const navigated: string[] = [];
-    const calls = stubFetch((path) => {
-      if (path.includes("/workflows/definitions")) {
-        return json({ data: [assistantDefinitionWire], nextCursor: null });
-      }
-      if (path.endsWith("/chat/workbenches")) {
-        return json({
-          id: "chan-adhoc",
-          title: NEW_WORKBENCH_TITLE,
-          kind: "workbench",
-          pinned: false,
-          participants: [],
-        });
-      }
-      if (path.endsWith("/chat/workbenches/chan-adhoc/messages")) {
-        return json({
-          id: "msg-1",
-          createdAt: "2026-01-01T00:00:00.000Z",
-          sender: { name: "Sawyer", address: "principal-1" },
-          parts: [{ kind: "text", text: "Plan the Q3 launch" }],
-        });
-      }
-      if (path.endsWith("/chat/workbenches/chan-adhoc/settings")) {
-        return json({
-          id: "chan-adhoc",
-          title: "Plan the Q3 launch",
-          kind: "workbench",
-          pinned: false,
-          participants: [],
-          settings: { "chat/name": "Plan the Q3 launch" },
-          contextWindow: { value: 0, source: "inherit" },
-        });
-      }
-      throw new Error(`unexpected fetch: ${path}`);
-    });
-
-    await createWorkbench(
-      "tnt_1",
-      (to) => navigated.push(to),
-      newQueryClient(),
-      "Plan the Q3 launch",
-    );
-
-    const settingsCall = calls.find((call) =>
-      call.path.endsWith("/chat/workbenches/chan-adhoc/settings"),
-    );
-    expect(JSON.parse(String(settingsCall?.init?.body))).toEqual({
-      "chat/name": "Plan the Q3 launch",
-    });
-    expect(navigated).toEqual(["/w/chan-adhoc"]);
-  });
-
-  test("an opening-message failure leaves a minted workbench recoverable", async () => {
-    stubFetch((path) => {
-      if (path.includes("/workflows/definitions")) {
-        return json({ data: [assistantDefinitionWire], nextCursor: null });
-      }
-      if (path.endsWith("/chat/workbenches")) {
-        return json({
-          id: "chan-recoverable",
-          title: NEW_WORKBENCH_TITLE,
-          kind: "workbench",
-          pinned: false,
-          participants: [],
-        });
-      }
-      if (path.endsWith("/chat/workbenches/chan-recoverable/invite")) {
-        return json({ address: "def-assistant@tnt-1.corbits.dev", definitionId: "def-assistant" });
-      }
-      // the opening message now posts through `@corbits/mailbox`'s
-      // `POST /me/inbox/send` rather than the chat route.
-      if (path.endsWith("/mailbox/me/inbox/send")) {
-        return json({ error: "agent launch failed" }, 409);
-      }
-      throw new Error(`unexpected fetch: ${path}`);
-    });
-
-    let cause: unknown;
-    try {
-      await createWorkbench(
-        "tnt_1",
-        () => undefined,
-        newQueryClient(),
-        "Research our next partner",
-        ["def-assistant"],
-      );
-    } catch (error) {
-      cause = error;
-    }
-
-    expect(cause).toBeInstanceOf(WorkbenchPostCreateError);
-    if (!(cause instanceof WorkbenchPostCreateError)) {
-      throw new Error("expected a recoverable post-create error");
-    }
-    expect(cause.workbenchId).toBe("chan-recoverable");
-    expect(cause.stage).toBe("opening-message");
-  });
-});
diff --git a/apps/web/src/instant-agent-create.ts b/apps/web/src/instant-agent-create.ts
deleted file mode 100644
index 36fe693de..000000000
--- a/apps/web/src/instant-agent-create.ts
+++ /dev/null
@@ -1,161 +0,0 @@
-// Every "create a workbench" affordance — the sidebar's "+", the command
-// palette's "New workbench", and the zero-workbench land-hop on `/` —
-// opens the picker (`pages/new-workbench-picker.tsx`) and calls
-// `createWorkbench` below once a person hits Create. deleted
-// workbench template picking (`@workbench/templates`): a new workbench is
-// a plain tenant + Myra now (its converge path deploys Myra), so
-// this mints an empty `kind: "workbench"` channel — no host, no
-// definitionId — and, when the prompt box supplied an opening message,
-// sends it and renames the room off it. Explicitly defining a brand-new
-// agent, with its own name/purpose/model/skills chosen up front, stays
-// `CreateAgentPanel`'s job (Settings → Agents), unchanged.
-
-import type { QueryClient } from "@tanstack/react-query";
-import {
-  createWorkbench as createWorkbenchChannel,
-  inviteAgent,
-  patchWorkbenchSettings,
-  sendInboxMessage,
-  workbenchesQueryKeyPrefix,
-} from "@/chat";
-import { reportError } from "@corbits/error-sink";
-
-import { listAgentDefinitions } from "./agents-api";
-import { autoNameFromFirstMessage, NEW_WORKBENCH_TITLE } from "./auto-workbench-title";
-import { findMyraDefinition } from "./myra-workbench";
-import { workbenchPath } from "./workbench-path";
-
-export { NEW_WORKBENCH_TITLE };
-
-export function refreshWorkbenchLists(
-  queryClient: QueryClient,
-  tenantId: string,
-  workbenchId: string,
-): void {
-  void queryClient
-    .invalidateQueries({
-      queryKey: workbenchesQueryKeyPrefix(tenantId),
-    })
-    .catch((cause) => {
-      reportError(cause, {
-        operation: "refresh_workbench_lists",
-        tenantId,
-        roomId: workbenchId,
-      });
-    });
-}
-
-/**
- * Marks the bench-not-ready precondition below as intentionally
- * user-facing: its `message` is authored copy, never a raw request path
- * or schema summary, so a caller can show it verbatim. Every other throw
- * on this path (`ApiQueryError`, `ChatApiError`, or a plain `Error` from a
- * package that hasn't opted in) must go through that error type's own
- * describer instead — allow-listing safe throws, rather than denylisting
- * unsafe ones, so a new error type added later fails safe (masked)
- * instead of leaking by default.
- */
-export class WorkbenchPreconditionError extends Error {
-  readonly kind: "setup-agent-missing";
-  constructor(message: string, kind: "setup-agent-missing") {
-    super(message);
-    this.kind = kind;
-  }
-}
-
-export class WorkbenchPostCreateError extends Error {
-  constructor(
-    readonly workbenchId: string,
-    readonly stage: "opening-message" | "rename",
-    cause: unknown,
-  ) {
-    super("The workbench was created, but setup did not finish.", { cause });
-  }
-}
-
-/**
- * Consumer-language stand-in for the system precondition this bench
- * hit: "no deployed setup agent" describes an internal implementation
- * detail, never something a person signing in for the first time
- * should have to parse.
- */
-const SETUP_AGENT_MISSING_MESSAGE =
-  "Your workbench is still finishing setup. Try again in a moment.";
-
-/**
- * The picker's "Create workbench" action: mints an empty `kind:
- * "workbench"` channel with no host and no `definitionId`. Talking to an
- * agent is clicking that agent (find-or-reopen its one DM); this function
- * is the create verb for a room.
- *
- * The bench has to be past setup — its default Myra definition deployed —
- * before a room can invite anyone into it, so a bench that isn't fails
- * with `WorkbenchPreconditionError` rather than minting a room nobody can
- * join.
- *
- * `queryClient` invalidates the workbenches list once every selected
- * agent has been invited — `ChatWorkspace`'s own in-room "Invite agent"
- * dialog does the same (`workbenchesQueryKeyPrefix`,
- * `chat-workspace.tsx`'s `refreshWorkbenchLists`) so the room the invite
- * landed in never shows a participant it already has data for as if it
- * never joined. Without this, the room this function `navigate`s to can
- * start life holding a `workbenches` query cached from before the last
- * invite resolved.
- *
- * `firstMessage`, when given (the picker's prompt box), is sent as the
- * signed-in person's own opening message once the room exists, and
- * renames the room off `NEW_WORKBENCH_TITLE` via `patchWorkbenchSettings`
- * (`chat/name`), matching the sidebar rename path.
- */
-export async function createWorkbench(
-  tenantId: string,
-  navigate: (to: string) => void,
-  queryClient: QueryClient,
-  firstMessage?: string,
-  selectedAgentDefinitionIds: readonly string[] = [],
-): Promise<void> {
-  const definitions = await listAgentDefinitions(tenantId);
-  if (findMyraDefinition(definitions) === undefined) {
-    throw new WorkbenchPreconditionError(SETUP_AGENT_MISSING_MESSAGE, "setup-agent-missing");
-  }
-  const workbench = await createWorkbenchChannel(tenantId, {
-    kind: "workbench",
-    name: NEW_WORKBENCH_TITLE,
-  });
-
-  if (firstMessage !== undefined && firstMessage.trim() !== "") {
-    try {
-      const invitedAgentAddresses: string[] = [];
-      for (const definitionId of new Set(selectedAgentDefinitionIds)) {
-        const invited = await inviteAgent(tenantId, workbench.id, definitionId);
-        invitedAgentAddresses.push(invited.address);
-      }
-      if (invitedAgentAddresses.length > 0) {
-        await sendInboxMessage(tenantId, invitedAgentAddresses, firstMessage);
-      }
-    } catch (cause) {
-      throw new WorkbenchPostCreateError(workbench.id, "opening-message", cause);
-    }
-    // Blank / ad-hoc mints stay "New Workbench" until named. When the
-    // prompt box already supplied the opening message, rename via the same
-    // `chat/name` settings PATCH the sidebar rename uses.
-    const autoTitle = autoNameFromFirstMessage(workbench.title, firstMessage);
-    if (autoTitle !== undefined) {
-      try {
-        await patchWorkbenchSettings(tenantId, workbench.id, {
-          "chat/name": autoTitle,
-        });
-      } catch (cause) {
-        throw new WorkbenchPostCreateError(workbench.id, "rename", cause);
-      }
-      refreshWorkbenchLists(queryClient, tenantId, workbench.id);
-    }
-  } else if (selectedAgentDefinitionIds.length > 0) {
-    for (const definitionId of new Set(selectedAgentDefinitionIds)) {
-      await inviteAgent(tenantId, workbench.id, definitionId);
-    }
-  }
-
-  refreshWorkbenchLists(queryClient, tenantId, workbench.id);
-  navigate(workbenchPath(workbench.id));
-}
diff --git a/apps/web/src/myra-workbench.test.ts b/apps/web/src/myra-workbench.test.ts
deleted file mode 100644
index 2c7d6de28..000000000
--- a/apps/web/src/myra-workbench.test.ts
+++ /dev/null
@@ -1,127 +0,0 @@
-import { afterEach, describe, expect, test } from "bun:test";
-
-import {
-  ensureMyraWorkbench,
-  findMyraDefinition,
-  isMyraWorkbenchId,
-  MYRA_WORKBENCH_TITLE,
-  resetMyraWorkbenchCache,
-} from "./myra-workbench";
-import type { AgentDefinition } from "./agents-api";
-
-describe("myra-workbench helpers", () => {
-  afterEach(() => {
-    resetMyraWorkbenchCache();
-  });
-
-  test("isMyraWorkbenchId is false until a workbench id is cached", () => {
-    expect(isMyraWorkbenchId("chan-1")).toBe(false);
-    expect(isMyraWorkbenchId(null)).toBe(false);
-  });
-
-  test("MYRA_WORKBENCH_TITLE is Myra", () => {
-    expect(MYRA_WORKBENCH_TITLE).toBe("Myra");
-  });
-});
-
-function definition(partial: { readonly id: string; readonly name: string }): AgentDefinition {
-  return {
-    id: partial.id,
-    tenantId: "tnt_1",
-    name: partial.name,
-    currentVersion: "1",
-    status: "deployed",
-    createdAt: "2026-01-01T00:00:00.000Z",
-    updatedAt: "2026-01-01T00:00:00.000Z",
-  };
-}
-
-describe("findMyraDefinition", () => {
-  test("matches the seeded assistant asset, not a display name", () => {
-    const definitions = [
-      definition({ id: "def-echo", name: "echo" }),
-      definition({ id: "def-assistant", name: "assistant" }),
-    ];
-    expect(findMyraDefinition(definitions)?.id).toBe("def-assistant");
-  });
-
-  test("returns undefined when no assistant definition is deployed", () => {
-    expect(findMyraDefinition([definition({ id: "def-echo", name: "echo" })])).toBeUndefined();
-  });
-});
-
-describe("ensureMyraWorkbench", () => {
-  const realFetch = globalThis.fetch;
-
-  afterEach(() => {
-    globalThis.fetch = realFetch;
-    resetMyraWorkbenchCache();
-  });
-
-  type RecordedCall = { readonly path: string; readonly init?: RequestInit };
-
-  function stubFetch(respond: (path: string) => Response): RecordedCall[] {
-    const calls: RecordedCall[] = [];
-    globalThis.fetch = ((input: RequestInfo | URL, init?: RequestInit) => {
-      const path = typeof input === "string" ? input : new URL(String(input)).pathname;
-      calls.push(init === undefined ? { path } : { path, init });
-      return Promise.resolve(respond(path));
-    }) as typeof fetch;
-    return calls;
-  }
-
-  const json = (body: unknown, status = 200) =>
-    new Response(JSON.stringify(body), {
-      status,
-      headers: { "content-type": "application/json" },
-    });
-
-  test("lands on Myra by issuing exactly the definition-keyed create, with no list-by-title lookup", async () => {
-    const calls = stubFetch((path) => {
-      if (path.includes("/workflows/definitions")) {
-        return json({
-          data: [definition({ id: "def-assistant", name: "assistant" })],
-          nextCursor: null,
-        });
-      }
-      if (path.endsWith("/chat/workbenches")) {
-        return json({
-          id: "chat-1",
-          title: "Myra",
-          kind: "chat",
-          pinned: false,
-          participants: [],
-        });
-      }
-      throw new Error(`unexpected fetch: ${path}`);
-    });
-
-    const result = await ensureMyraWorkbench("tnt_1");
-
-    expect(result).toEqual({ kind: "ready", workbenchId: "chat-1" });
-    expect(calls.some((call) => call.path.includes("kind=workbench"))).toBe(false);
-    expect(calls.some((call) => call.path.includes("kind=chat"))).toBe(false);
-    const createCall = calls.find((call) => call.path.endsWith("/chat/workbenches"));
-    expect(createCall?.init?.method).toBe("POST");
-    expect(JSON.parse(String(createCall?.init?.body))).toEqual({
-      kind: "chat",
-      definitionId: "def-assistant",
-      name: "Myra",
-      reuseExisting: true,
-    });
-    expect(isMyraWorkbenchId("chat-1")).toBe(true);
-  });
-
-  test("errors when no Myra definition is deployed for the tenant", async () => {
-    stubFetch((path) => {
-      if (path.includes("/workflows/definitions")) {
-        return json({ data: [], nextCursor: null });
-      }
-      throw new Error(`unexpected fetch: ${path}`);
-    });
-
-    const result = await ensureMyraWorkbench("tnt_1");
-
-    expect(result.kind).toBe("error");
-  });
-});
diff --git a/apps/web/src/myra-workbench.ts b/apps/web/src/myra-workbench.ts
deleted file mode 100644
index dd8b706c6..000000000
--- a/apps/web/src/myra-workbench.ts
+++ /dev/null
@@ -1,56 +0,0 @@
-// Default Myra chat: the product land surface. Composition only — the
-// find-or-create logic itself is `@/chat`'s generic
-// `createDefaultAgentWorkbench`; this file's job is to name Myra as the
-// configured agent and wire it to this app's workflow-definitions fetch.
-
-import { createDefaultAgentWorkbench, findDefinitionByAssetName } from "@/chat";
-import { WORKFLOW_CATALOG } from "@corbits/workflows/catalog";
-
-import { listAgentDefinitions, type AgentDefinition } from "./agents-api";
-
-export const MYRA_WORKBENCH_TITLE = "Myra";
-
-/** The deployed workflow asset backing Myra (`myra-source.ts` /
- * `myra-deploy.ts` deploy it as `assistant`, stamped with catalog
- * displayName "Myra"). A chat's `definitionId` names this deployed
- * definition's row id, never the asset name itself. */
-const MYRA_ASSET_NAME = WORKFLOW_CATALOG.find(
-  (entry) => entry.displayName === MYRA_WORKBENCH_TITLE,
-)?.assetName;
-
-export type { EnsureDefaultAgentWorkbenchResult as EnsureMyraWorkbenchResult } from "@/chat";
-
-const myraWorkbench = createDefaultAgentWorkbench({
-  title: MYRA_WORKBENCH_TITLE,
-  assetName: MYRA_ASSET_NAME,
-});
-
-/** The last workbench id `ensureMyraWorkbench` resolved to, for the shell's
- * col2-wide derivation: "Myra is the active surface" reduces to
- * "the open workbench is the one Talk-to-Myra last landed us on". */
-export function isMyraWorkbenchId(workbenchId: string | null): boolean {
-  return myraWorkbench.isCachedWorkbenchId(workbenchId);
-}
-
-/** Test helper — drop the cached id between cases. */
-export function resetMyraWorkbenchCache(): void {
-  myraWorkbench.resetCache();
-}
-
-/** Myra's deployed agent definition, matched by the seeded `assistant`
- * asset name — never by display name, which is a UI label, not a wire
- * identifier. */
-export function findMyraDefinition(
-  definitions: readonly AgentDefinition[],
-): AgentDefinition | undefined {
-  return findDefinitionByAssetName(definitions, MYRA_ASSET_NAME);
-}
-
-/**
- * Create (or reopen) the 1:1 chat against Myra's deployed agent definition —
- * the server's `definitionId` dedupe on `POST /workbenches` is the one
- * find-or-reopen path; this call always issues that create and trusts it.
- */
-export function ensureMyraWorkbench(tenantId: string) {
-  return myraWorkbench.ensure(tenantId, listAgentDefinitions);
-}
diff --git a/apps/web/src/pages/chat-page.tsx b/apps/web/src/pages/chat-page.tsx
deleted file mode 100644
index d87b0fd01..000000000
--- a/apps/web/src/pages/chat-page.tsx
+++ /dev/null
@@ -1,235 +0,0 @@
-// Workbench surface for the main stage. `/w` and `/w/:workbenchId` (plus legacy
-// `/chat` prefixes) render the conversation here — not in the canvas.
-// Canvas stays auxiliary (profiles and similar) and opens on demand from
-// this workspace.
-
-import { libraryArtifactPath } from "@/library";
-import { describeApiError } from "@/lib/api-query";
-import { ChatWorkspace, fetchWorkbenchBlob, type Part } from "@/chat";
-import { getResolvedCatalog, hasUsableModel as computeHasUsableModel } from "@/settings/inference";
-import { useQuery, useQueryClient } from "@tanstack/react-query";
-import { useCallback, useEffect, useMemo } from "react";
-
-import { fetchArtifactDetail } from "../api";
-import { createChatApprovalActions } from "../approval-actions";
-import { useBench } from "../bench-context";
-import { useSignOut, useSessionUser } from "../navigation";
-
-import {
-  artifactContentFromBlob,
-  artifactContentFromBlobError,
-  artifactContentFromDetail,
-  artifactContentFromDetailError,
-} from "../chat-artifact-open";
-import {
-  workbenchIdFromPath,
-  workbenchPath,
-  workbenchSettingsPath,
-  workbenchSettingsSectionFromPath,
-  workbenchSettingsEntityIdFromPath,
-  isWorkbenchSettingsPath,
-} from "../workbench-path";
-import { reportWorkbenchNotFound } from "../workbench-not-found-event";
-import { recordLastWorkbenchId } from "../last-workbench";
-import { MISSION_CONTROL_PATH, NEW_WORKBENCH_PATH } from "../routes";
-import { useOpenArtifactInCanvas, useOpenProfileInCanvas } from "../shell/canvas-availability";
-import { useRegisterComposerInsert } from "../shell/composer-insertion";
-import { StageTopBar } from "../shell/stage-top-bar";
-import { tenantResolutionFromBench } from "../shell/tenant-resolution";
-
-export function ChatPage({
-  path,
-  navigate,
-}: {
-  readonly path: string;
-  readonly navigate: (to: string) => void;
-}) {
-  const bench = useBench();
-  const onSignIn = useSignOut();
-  const sessionUser = useSessionUser();
-  const workbenchId = workbenchIdFromPath(path);
-
-  const settingsOpen = isWorkbenchSettingsPath(path);
-  const settingsSection = workbenchSettingsSectionFromPath(path) ?? "general";
-  const settingsEntityId = settingsOpen
-    ? workbenchSettingsEntityIdFromPath(path, settingsSection)
-    : null;
-  const openProfile = useOpenProfileInCanvas();
-  const registerComposerInsert = useRegisterComposerInsert();
-  const openArtifactInCanvas = useOpenArtifactInCanvas();
-  const tenant = tenantResolutionFromBench(bench);
-  const principalId = bench.selectedPrincipalId ?? undefined;
-  const queryClient = useQueryClient();
-  const tenantId = bench.selectedTenantId;
-
-  // Same display name the sidebar account row already shows: the
-  // auth session's name, which sign-up seeds from the email local-part when
-  // no profile name was typed. Without this, chat-ui falls back to "Member"
-  // for the reader's own presence/message avatar.
-  const currentUser =
-    principalId === undefined
-      ? undefined
-      : {
-          principalId,
-          ...(sessionUser !== undefined
-            ? {
-                name:
-                  sessionUser.name.trim().length > 0
-                    ? sessionUser.name.trim()
-                    : (sessionUser.email.split("@")[0] ?? sessionUser.email),
-                handle: sessionUser.email,
-              }
-            : {}),
-        };
-
-  // Files' workbench-first lens reads this back to default to
-  // "this workbench" when the person just came from one.
-  useEffect(() => {
-    if (tenantId === null || workbenchId === null) return;
-    recordLastWorkbenchId(tenantId, workbenchId);
-  }, [tenantId, workbenchId]);
-
-  // Who's live in this workbench right now is derived inside `ChatWorkspace`
-  // itself now, off the same `/stream` connection as everything
-  // else — no separate `@corbits/presence` room/heartbeat for this surface
-  // any more (that stack still backs the artifact canvas's cursor sync,
-  // which has no chat stream of its own to piggyback on).
-  const approvalActions = useMemo(
-    () => (tenantId === null ? undefined : createChatApprovalActions(tenantId, queryClient)),
-    [tenantId, queryClient],
-  );
-  // The in-chat "Fix this connection" affordance's deep link — Settings
-  // is where a credential now lives (the stock credentials route), so
-  // there is no provider-specific hop left to make.
-  const handleFixConnection = useCallback(() => navigate("/settings"), [navigate]);
-
-  // whether this tenant can actually run inference — never
-  // whether a `model_provider` row merely exists, since seeding mints
-  // that row with no credential attached. The same resolved-catalog
-  // read `resolveModelSources` acts on at launch, so a model only
-  // carries an offering once a real credential backs it.
-  const resolvedCatalogQuery = useQuery({
-    queryKey: ["chat-page", "resolved-catalog", tenantId],
-    queryFn: () => getResolvedCatalog(tenantId ?? ""),
-    enabled: tenantId !== null,
-  });
-  const hasUsableModel =
-    resolvedCatalogQuery.data !== undefined
-      ? computeHasUsableModel(resolvedCatalogQuery.data)
-      : undefined;
-  const handleConnectModel = useCallback(() => {
-    navigate("/settings/connections");
-  }, [navigate]);
-
-  // A file part with an `artifactId` links back to a real Library row
-  // — this always resolves through the Library artifacts read
-  // surface for that id, the same one `LibraryRoute` reads, never raw blob
-  // bytes. Only a part with no `artifactId` (a plain human upload the
-  // platform never diverted into an artifact) falls back to reading the
-  // bytes off the chat platform's own blob route. Either path renders
-  // through the same typed renderers Library and the canvas already share.
-  const openArtifact = useCallback(
-    (part: Part & { kind: "file" }) => {
-      if (tenantId === null) return;
-      if (part.artifactId !== undefined) {
-        const artifactId = part.artifactId;
-        void fetchArtifactDetail(tenantId, artifactId)
-          .then((detail) => {
-            openArtifactInCanvas(artifactContentFromDetail(tenantId, detail));
-          })
-          .catch((err) => {
-            openArtifactInCanvas(
-              artifactContentFromDetailError(
-                part,
-                artifactId,
-                describeApiError(err, "loading this artifact"),
-              ),
-            );
-          });
-        return;
-      }
-      if (part.blobId === undefined || workbenchId === null) return;
-      const blobId = part.blobId;
-      void fetchWorkbenchBlob(tenantId, workbenchId, blobId)
-        .then((contentBase64) => {
-          openArtifactInCanvas(artifactContentFromBlob(part, blobId, contentBase64));
-        })
-        .catch((err) => {
-          openArtifactInCanvas(
-            artifactContentFromBlobError(
-              part,
-              blobId,
-              describeApiError(err, "loading this attachment"),
-            ),
-          );
-        });
-    },
-    [tenantId, workbenchId, openArtifactInCanvas],
-  );
-
-  // The chip's "Open in Library" affordance — only ever offered for a part
-  // that carries an `artifactId` (see `ArtifactChip`), so this always has a
-  // real row to deep-link to.
-  const openArtifactInLibrary = useCallback(
-    (part: Part & { kind: "file" }) => {
-      if (part.artifactId === undefined) return;
-      navigate(libraryArtifactPath(part.artifactId));
-    },
-    [navigate],
-  );
-
-  // Hub-zero T3: the room GitHub card is unbound on
-  // purpose — its state/start-reviewing routes are deleted and no native
-  // equivalent exists yet, so it renders its no-port disabled framing
-  // until a connections follow-up rebinds it. Connect/disconnect itself
-  // lives in Settings › Connections.
-  const workspace = (
-    <ChatWorkspace
-      tenant={tenant}
-      {...(currentUser !== undefined ? { currentUser } : {})}
-      workbenchId={workbenchId}
-      onWorkbenchChange={(nextWorkbenchId) => navigate(workbenchPath(nextWorkbenchId))}
-      onOpenProfile={openProfile}
-      registerComposerInsert={registerComposerInsert}
-      settingsOpen={settingsOpen}
-      onSettingsOpenChange={(open, section, entityId) => {
-        if (workbenchId === null) return;
-        navigate(
-          open
-            ? workbenchSettingsPath(workbenchId, section ?? settingsSection, entityId)
-            : workbenchPath(workbenchId),
-        );
-      }}
-      settingsSection={settingsSection}
-      onSettingsSectionChange={(section) => {
-        if (workbenchId === null) return;
-        navigate(workbenchSettingsPath(workbenchId, section));
-      }}
-      settingsEntityId={settingsEntityId}
-      onSettingsEntityIdChange={(entityId) => {
-        if (workbenchId === null) return;
-        navigate(workbenchSettingsPath(workbenchId, settingsSection, entityId ?? undefined));
-      }}
-      onOpenArtifact={openArtifact}
-      onOpenArtifactInLibrary={openArtifactInLibrary}
-      onFixConnection={handleFixConnection}
-      {...(hasUsableModel !== undefined ? { hasUsableModel } : {})}
-      onConnectModel={handleConnectModel}
-      {...(approvalActions !== undefined ? { approvalActions } : {})}
-      onWorkbenchNotFound={reportWorkbenchNotFound}
-      onGoToMissionControl={() => navigate(MISSION_CONTROL_PATH)}
-      onNewWorkbench={() => navigate(NEW_WORKBENCH_PATH)}
-      onBackToWorkbenchList={() => navigate(workbenchPath(null))}
-      {...(onSignIn !== undefined ? { onSignIn } : {})}
-      headerSlot={(chrome) => (
-        <StageTopBar
-          crumbs={chrome.crumbs}
-          {...(chrome.subtitle !== undefined ? { subtitle: chrome.subtitle } : {})}
-          {...(chrome.actions !== undefined ? { actions: chrome.actions } : {})}
-        />
-      )}
-    />
-  );
-
-  return <div className="flex h-full min-h-0 flex-col">{workspace}</div>;
-}
diff --git a/apps/web/src/pages/insights-page.tsx b/apps/web/src/pages/insights-page.tsx
index b9c1d3248..d02c37332 100644
--- a/apps/web/src/pages/insights-page.tsx
+++ b/apps/web/src/pages/insights-page.tsx
@@ -33,7 +33,7 @@ import { useEffect, useState } from "react";
 
 import { workflowRunStatuses, type WorkflowRunStatus } from "@intx/types";
 import { SignedOutNotice, type APIQuery } from "@/lib/api-query";
-import { workbenchesQueryKey, listWorkbenches } from "@/chat";
+import { workbenchesQueryKey, listWorkbenches } from "@/chat/workbench-tenants";
 
 import { useBench } from "../bench-context";
 import { resolveWorkbenchInsightsScope } from "../insights-workbench-scope";
@@ -57,7 +57,6 @@ import {
   useTenantQuery,
   type ScheduledWorkflowDefinition,
 } from "../routines-api";
-import { WorkbenchTimelineRoute } from "./workbench-timeline";
 
 export function formatWhen(iso: string): string {
   const date = new Date(iso);
@@ -630,17 +629,11 @@ export function InsightsPage({
  * tenant-scoped fetch.
  */
 function InsightsWorkbenchPage({
-  workbenchId,
   workbenchesLoading,
   resolution,
-  benchTenantId,
-  onOpenRun,
 }: {
-  readonly workbenchId: string;
   readonly workbenchesLoading: boolean;
   readonly resolution: ReturnType<typeof resolveWorkbenchInsightsScope>;
-  readonly benchTenantId: string | null;
-  readonly onOpenRun: (id: string) => void;
 }) {
   if (workbenchesLoading) {
     return (
@@ -687,10 +680,10 @@ function InsightsWorkbenchPage({
       />
       <div className="min-h-0 flex-1 overflow-y-auto">
         <PageShell width="full" className="page-fill">
-          <WorkbenchTimelineRoute
-            benchTenantId={benchTenantId}
-            workbenchId={workbenchId}
-            onOpenRun={onOpenRun}
+          <RichEmptyState
+            icon={<ChartBar />}
+            title="This workbench's activity lives in its room"
+            description="Open the workbench to read its conversation."
           />
         </PageShell>
       </div>
@@ -744,7 +737,6 @@ export function InsightsRoute({ path }: { readonly path?: string }) {
 function InsightsWorkbenchPageRoute({
   workbenchId,
   benchTenantId,
-  onOpenRun,
 }: {
   readonly workbenchId: string;
   readonly benchTenantId: string | null;
@@ -752,15 +744,7 @@ function InsightsWorkbenchPageRoute({
 }) {
   const { workbenches, chats, isLoading } = useWorkbenchAndChatLists(benchTenantId);
   const resolution = resolveWorkbenchInsightsScope([...workbenches, ...chats], workbenchId);
-  return (
-    <InsightsWorkbenchPage
-      workbenchId={workbenchId}
-      workbenchesLoading={isLoading}
-      resolution={resolution}
-      benchTenantId={benchTenantId}
-      onOpenRun={onOpenRun}
-    />
-  );
+  return <InsightsWorkbenchPage workbenchesLoading={isLoading} resolution={resolution} />;
 }
 
 function useWorkbenchAndChatLists(tenantId: string | null) {
diff --git a/apps/web/src/pages/new-workbench-picker.tsx b/apps/web/src/pages/new-workbench-picker.tsx
index cb1447b96..1cf394726 100644
--- a/apps/web/src/pages/new-workbench-picker.tsx
+++ b/apps/web/src/pages/new-workbench-picker.tsx
@@ -1,236 +1,92 @@
-// workbench template picking is gone — a new workbench is a
-// plain tenant + Myra (its converge path deploys Myra behind the
-// scenes). This screen is just the prompt box: say what you want and hit
-// Enter, or open an empty channel and add people/agents as you go.
+// A new workbench is a child tenant plus the agents you put in it. This
+// screen is the prompt box: say what you want and hit Enter, or open an
+// empty room and add people and agents as you go.
 
 import { Button, toast } from "@corbits/react-ui";
-import { useDismissablePopover } from "@corbits/react-ui/hooks/use-dismissable-popover";
 import { PaperPlaneRight } from "@/lib/icons";
-import {
-  ChatApiError,
-  CHAT_STRINGS,
-  describeChatError,
-  listTenantInvitableDefinitions,
-  WorkbenchLoadingState,
-} from "@/chat";
-import { humanizeSlug } from "@/chat/wire/display-name";
-import { useEffect, useRef, useState } from "react";
-import { useQuery, useQueryClient } from "@tanstack/react-query";
-import { ApiQueryError, describeApiError } from "@/lib/api-query";
+import { CHAT_STRINGS, WorkbenchLoadingState } from "@/chat";
+import { useRef, useState } from "react";
+import { useMutation, useQueryClient } from "@tanstack/react-query";
 import { reportError } from "@corbits/error-sink";
 
-import { CreateAgentPanel } from "./create-agent-panel";
-import { getAgentRun } from "../agents-api";
 import { useBench } from "../bench-context";
-import {
-  createWorkbench,
-  refreshWorkbenchLists,
-  WorkbenchPostCreateError,
-  WorkbenchPreconditionError,
-} from "../instant-agent-create";
+import { chatKeys } from "../chat-path";
+import { createWorkbench, WorkbenchCreateError } from "../workbench-create";
 import { useNavigate } from "../navigation";
 import { StageTopBar } from "../shell/stage-top-bar";
 import { workbenchPath } from "../workbench-path";
 
 const GENERIC_CREATE_FAILURE = "Something went wrong creating this workbench. Try again.";
 
-/**
- * Allow-lists what's safe to show verbatim, rather than denylisting
- * what to hide — a new error type `createWorkbench`'s path starts
- * throwing later lands here unrecognized and falls to the generic
- * message, not into the toast raw. Only `WorkbenchPreconditionError`
- * carries authored, always-safe copy; `ApiQueryError` and `ChatApiError`
- * both embed raw request paths and schema summaries in `.message` and
- * must go through their own describer, never shown directly.
- */
+/** Allow-lists what is safe to show verbatim: only the authored
+ * stage copy, never a raw request path or schema summary. */
 export function describeWorkbenchCreateFailure(cause: unknown, refId?: string): string {
-  if (cause instanceof WorkbenchPostCreateError) {
-    const message =
-      cause.stage === "opening-message"
-        ? "Workbench created, but we couldn't send the opening message or add the selected agent. Try again from the room."
-        : "Workbench created, but we couldn't rename it.";
-    return refId === undefined ? message : `${message} Reference: ${refId}`;
-  }
-  if (cause instanceof WorkbenchPreconditionError) return cause.message;
-  if (cause instanceof ApiQueryError) {
-    return describeApiError(cause, "creating this workbench");
-  }
-  if (cause instanceof ChatApiError) {
-    return describeChatError(cause, GENERIC_CREATE_FAILURE);
-  }
-  return GENERIC_CREATE_FAILURE;
+  if (!(cause instanceof WorkbenchCreateError)) return GENERIC_CREATE_FAILURE;
+  const message =
+    cause.stage === "opening-message"
+      ? "Workbench created, but we couldn't send the opening message. Try again from the room."
+      : cause.stage === "deploy"
+        ? "Workbench created, but its agent couldn't be deployed into it. Try again from the room."
+        : GENERIC_CREATE_FAILURE;
+  return refId === undefined ? message : `${message} Reference: ${refId}`;
 }
 
 const PROMPT_PLACEHOLDER = "What do you want your Workbench to do?";
-const AGENT_LISTBOX_ID = "new-workbench-agent-listbox";
 
-function agentDisplayName({
-  name,
-  description,
-}: {
-  readonly name: string;
-  readonly description?: string;
-}): string {
-  return description === undefined || description === "" ? humanizeSlug(name) : description;
+/** A room's name is its opening ask, trimmed — an empty room is just
+ * "Workbench" until it is renamed. */
+function workbenchName(prompt: string): string {
+  const trimmed = prompt.trim();
+  return trimmed === "" ? "Workbench" : trimmed.slice(0, 60);
 }
 
 export function NewWorkbenchPickerRoute() {
   const navigate = useNavigate();
   const queryClient = useQueryClient();
   const { selectedTenantId } = useBench();
-  const currentTenantIdRef = useRef(selectedTenantId);
-  useEffect(() => {
-    currentTenantIdRef.current = selectedTenantId;
-    return () => {
-      currentTenantIdRef.current = null;
-    };
-  }, [selectedTenantId]);
   const [prompt, setPrompt] = useState("");
-  const [selectedAgentDefinitionIds, setSelectedAgentDefinitionIds] = useState<readonly string[]>(
-    [],
-  );
-  const [agentPickerOpen, setAgentPickerOpen] = useState(false);
-  const [createAgentOpen, setCreateAgentOpen] = useState(false);
-  const [agentQuery, setAgentQuery] = useState("");
-  const [activeAgentIndex, setActiveAgentIndex] = useState(0);
-  const [creating, setCreating] = useState(false);
-  // Set only when `createWorkbench` hit the missing-setup-agent
-  // precondition — thrown only after its own native definitions read found
-  // no setup agent, so that read is the readiness check, never a guess
-  // from the error alone. Distinct from `creating`'s loader: this is a
-  // dead end until setup finishes, not a request in flight.
-  const [stillSettingUp, setStillSettingUp] = useState(false);
   const promptRef = useRef<HTMLTextAreaElement | null>(null);
-  const {
-    rootRef: agentPickerRootRef,
-    triggerRef: agentPickerTriggerRef,
-    close: dismissAgentPicker,
-  } = useDismissablePopover<HTMLDivElement, HTMLButtonElement>({
-    closeOnEscape: false,
-    open: agentPickerOpen,
-    onOpenChange: setAgentPickerOpen,
-  });
-  const invitableAgents = useQuery({
-    queryKey: ["tenant", selectedTenantId, "invitable-definitions"],
-    queryFn: () => {
-      if (selectedTenantId === null) {
-        throw new Error("An account is required to load agents.");
-      }
-      return listTenantInvitableDefinitions(selectedTenantId);
-    },
-    enabled: selectedTenantId !== null,
-  });
-  // The last attempted create, so "Try again" (both the still-setting-up
-  // dead end and a plain toast-and-retry) replays the exact same request
-  // rather than silently falling back to blank.
-  const lastAttemptRef = useRef<{
-    readonly firstMessage: string | undefined;
-    readonly selectedIds: readonly string[];
-  } | null>(null);
-
-  // The prompt box only exists in the DOM once neither dead-end state is
-  // showing — an unconditional mount-time effect would fire while a dead
-  // end renders instead, before `promptRef` has anything to focus.
-  const showingPrompt = !stillSettingUp && !creating;
-  useEffect(() => {
-    if (showingPrompt) promptRef.current?.focus();
-  }, [showingPrompt]);
 
-  useEffect(() => {
-    setAgentPickerOpen(false);
-    setCreateAgentOpen(false);
-    setAgentQuery("");
-    setActiveAgentIndex(0);
-    setSelectedAgentDefinitionIds([]);
-  }, [selectedTenantId]);
-
-  useEffect(() => {
-    if (invitableAgents.data === undefined) return;
-    const availableDefinitionIds = new Set(invitableAgents.data.map((agent) => agent.id));
-    setSelectedAgentDefinitionIds((current) => {
-      const next = current.filter((id) => availableDefinitionIds.has(id));
-      return next.length === current.length ? current : next;
-    });
-  }, [invitableAgents.data]);
-
-  const filteredAgents = (invitableAgents.data ?? []).filter((agent) => {
-    const query = agentQuery.trim().toLocaleLowerCase();
-    return (
-      query === "" ||
-      agentDisplayName(agent).toLocaleLowerCase().includes(query) ||
-      agent.name.toLocaleLowerCase().includes(query)
-    );
-  });
-  const selectedAgents = (invitableAgents.data ?? []).filter((agent) =>
-    selectedAgentDefinitionIds.includes(agent.id),
-  );
-
-  async function handleCreate(firstMessage?: string, selectedIds: readonly string[] = []) {
-    if (selectedTenantId === null || creating) return;
-    lastAttemptRef.current = { firstMessage, selectedIds };
-    setCreating(true);
-    setStillSettingUp(false);
-    try {
-      await createWorkbench(selectedTenantId, navigate, queryClient, firstMessage, selectedIds);
-    } catch (cause) {
-      if (cause instanceof WorkbenchPostCreateError) {
-        const refId = reportError(cause, {
-          operation: "workbench_post_create",
-          tenantId: selectedTenantId,
-          roomId: cause.workbenchId,
-          extra: { stage: cause.stage },
-        });
-        refreshWorkbenchLists(queryClient, selectedTenantId, cause.workbenchId);
-        navigate(workbenchPath(cause.workbenchId));
-        toast(describeWorkbenchCreateFailure(cause, refId));
-        return;
-      }
-      if (cause instanceof WorkbenchPreconditionError && cause.kind === "setup-agent-missing") {
-        setCreating(false);
-        setStillSettingUp(true);
-        return;
-      }
-      // Every remaining cause is a genuinely failed create: report it with
-      // operation context and a quotable refId rather than a log line alone.
+  const create = useMutation({
+    mutationFn: ({
+      benchTenantId,
+      openingMessage,
+    }: {
+      readonly benchTenantId: string;
+      readonly openingMessage: string | undefined;
+    }) =>
+      createWorkbench({
+        benchTenantId,
+        name: workbenchName(openingMessage ?? ""),
+        ...(openingMessage !== undefined ? { openingMessage } : {}),
+      }),
+    onSuccess: (tenantId, variables) => {
+      void queryClient.invalidateQueries({
+        queryKey: chatKeys.childTenants(variables.benchTenantId),
+      });
+      navigate(workbenchPath(tenantId));
+    },
+    onError: (cause: unknown) => {
       const refId = reportError(cause, {
         operation: "workbench_create",
-        tenantId: selectedTenantId,
+        ...(selectedTenantId !== null ? { tenantId: selectedTenantId } : {}),
       });
       toast(describeWorkbenchCreateFailure(cause, refId));
-      setCreating(false);
-    }
-  }
+    },
+  });
 
-  function retryLastAttempt() {
-    const attempt = lastAttemptRef.current;
-    if (attempt === null) return;
-    void handleCreate(attempt.firstMessage, attempt.selectedIds);
+  function startCreate(openingMessage?: string) {
+    if (selectedTenantId === null || create.isPending) return;
+    create.mutate({
+      benchTenantId: selectedTenantId,
+      ...(openingMessage !== undefined ? { openingMessage } : { openingMessage: undefined }),
+    });
   }
 
   function handlePromptSubmit() {
     const trimmed = prompt.trim();
     if (trimmed === "") return;
-    void handleCreate(trimmed, selectedAgentDefinitionIds);
-  }
-
-  function toggleAgent(definitionId: string) {
-    setSelectedAgentDefinitionIds((current) =>
-      current.includes(definitionId)
-        ? current.filter((id) => id !== definitionId)
-        : [...current, definitionId],
-    );
-  }
-
-  function closeAgentPicker() {
-    setAgentQuery("");
-    setActiveAgentIndex(0);
-    dismissAgentPicker();
-  }
-
-  function openAgentPicker() {
-    setAgentPickerOpen(true);
-    setAgentQuery("");
-    setActiveAgentIndex(0);
+    startCreate(trimmed);
   }
 
   return (
@@ -244,29 +100,15 @@ export function NewWorkbenchPickerRoute() {
         }
       />
       <div className="new-workbench-picker">
-        {stillSettingUp ? (
-          <div className="new-workbench-picker-not-ready">
-            <h3>Still setting up your workbench</h3>
-            <p className="new-workbench-picker-sub">
-              Your account&apos;s agents are finishing setup in the background. This usually takes
-              under a minute — try again in a moment.
-            </p>
-            <Button type="button" variant="outline" onClick={retryLastAttempt}>
-              Try again
-            </Button>
-          </div>
-        ) : creating ? (
-          // `delayMs={0}`: we already know this is a genuine wait the
-          // instant the person hits Enter, so the default "hold back
-          // briefly in case it resolves fast" delay only bought a blank
-          // pane here (finding #3) — show the loader outright
-          // instead of leaving a gap before it mounts.
+        {create.isPending ? (
+          // `delayMs={0}`: this is a genuine wait the instant the person
+          // hits Enter, so the default hold-back only bought a blank pane.
           <WorkbenchLoadingState delayMs={0} title="Setting up your workbench…" />
         ) : (
           <>
             <h3>What do you want your Workbench to do?</h3>
             <p className="new-workbench-picker-sub">
-              Tell it what you're trying to get done. Takes about ten seconds.
+              Tell it what you&apos;re trying to get done. Takes about ten seconds.
             </p>
 
             <form
@@ -311,139 +153,6 @@ export function NewWorkbenchPickerRoute() {
                 </div>
               </div>
               <div className="new-workbench-prompt-actions">
-                <div className="new-workbench-agent-selection">
-                  <span>In the room</span>
-                  {selectedAgents.map((agent) => (
-                    <span key={agent.id} className="new-workbench-agent-chip">
-                      {agentDisplayName(agent)}
-                      <button
-                        type="button"
-                        aria-label={`Remove ${agentDisplayName(agent)}`}
-                        onClick={() => toggleAgent(agent.id)}
-                      >
-                        ×
-                      </button>
-                    </span>
-                  ))}
-                  {invitableAgents.isLoading ? (
-                    <span className="new-workbench-agent-status">Loading agents…</span>
-                  ) : invitableAgents.isError ? (
-                    <span className="new-workbench-agent-status" role="status">
-                      Couldn&apos;t load agents. You can still start without one.
-                    </span>
-                  ) : (
-                    <div ref={agentPickerRootRef} className="new-workbench-agent-picker">
-                      <button
-                        ref={agentPickerTriggerRef}
-                        type="button"
-                        className="new-workbench-add-agent"
-                        aria-controls={AGENT_LISTBOX_ID}
-                        aria-expanded={agentPickerOpen}
-                        onClick={() => (agentPickerOpen ? closeAgentPicker() : openAgentPicker())}
-                      >
-                        + Add agent
-                      </button>
-                      {agentPickerOpen ? (
-                        <div className="new-workbench-agent-popover">
-                          <input
-                            autoFocus
-                            className="new-workbench-agent-search"
-                            type="search"
-                            placeholder="Find an agent…"
-                            value={agentQuery}
-                            role="combobox"
-                            aria-autocomplete="list"
-                            aria-controls={AGENT_LISTBOX_ID}
-                            aria-expanded="true"
-                            aria-activedescendant={
-                              filteredAgents[activeAgentIndex] === undefined
-                                ? undefined
-                                : `new-workbench-agent-${filteredAgents[activeAgentIndex].id}`
-                            }
-                            onChange={(event) => {
-                              setAgentQuery(event.target.value);
-                              setActiveAgentIndex(0);
-                            }}
-                            onKeyDown={(event) => {
-                              if (event.key === "ArrowDown") {
-                                event.preventDefault();
-                                setActiveAgentIndex((current) =>
-                                  Math.min(current + 1, filteredAgents.length - 1),
-                                );
-                              }
-                              if (event.key === "ArrowUp") {
-                                event.preventDefault();
-                                setActiveAgentIndex((current) => Math.max(current - 1, 0));
-                              }
-                              if (event.key === "Enter") {
-                                // Implicit form submission would otherwise
-                                // fire on a miss, creating a workbench the
-                                // operator did not ask for.
-                                event.preventDefault();
-                                const activeAgent = filteredAgents[activeAgentIndex];
-                                if (activeAgent !== undefined) {
-                                  toggleAgent(activeAgent.id);
-                                }
-                              }
-                              if (event.key === "Escape") {
-                                event.preventDefault();
-                                closeAgentPicker();
-                              }
-                            }}
-                          />
-                          {filteredAgents.length === 0 ? (
-                            <p className="new-workbench-agent-empty">
-                              {invitableAgents.data?.length === 0
-                                ? "No agents are available yet."
-                                : "No agents match that search."}
-                            </p>
-                          ) : (
-                            <div id={AGENT_LISTBOX_ID} role="listbox" aria-label="Available agents">
-                              {filteredAgents.map((agent, index) => {
-                                const selected = selectedAgentDefinitionIds.includes(agent.id);
-                                return (
-                                  <button
-                                    key={agent.id}
-                                    id={`new-workbench-agent-${agent.id}`}
-                                    type="button"
-                                    role="option"
-                                    aria-selected={selected}
-                                    className={
-                                      index === activeAgentIndex
-                                        ? "new-workbench-agent-option is-active"
-                                        : "new-workbench-agent-option"
-                                    }
-                                    onMouseMove={() => setActiveAgentIndex(index)}
-                                    onClick={() => toggleAgent(agent.id)}
-                                  >
-                                    <span className="new-workbench-agent-option-name">
-                                      {agentDisplayName(agent)}
-                                    </span>
-                                    <span className="new-workbench-agent-option-handle">
-                                      {agent.name}
-                                    </span>
-                                    {selected ? <span aria-hidden="true">✓</span> : null}
-                                  </button>
-                                );
-                              })}
-                            </div>
-                          )}
-                          <Button
-                            type="button"
-                            variant="ghost"
-                            className="mt-2 w-full justify-start border-t border-border"
-                            onClick={() => {
-                              closeAgentPicker();
-                              setCreateAgentOpen(true);
-                            }}
-                          >
-                            + Create agent
-                          </Button>
-                        </div>
-                      ) : null}
-                    </div>
-                  )}
-                </div>
                 <Button
                   type="submit"
                   aria-label="Start this workbench"
@@ -458,8 +167,8 @@ export function NewWorkbenchPickerRoute() {
             <button
               type="button"
               className="new-workbench-empty-channel"
-              disabled={creating || selectedTenantId === null}
-              onClick={() => void handleCreate()}
+              disabled={create.isPending || selectedTenantId === null}
+              onClick={() => startCreate()}
             >
               Or <span>just open an empty channel</span> — nobody is in it yet, add people and
               agents as you go.
@@ -467,29 +176,6 @@ export function NewWorkbenchPickerRoute() {
           </>
         )}
       </div>
-      {selectedTenantId !== null && createAgentOpen ? (
-        <CreateAgentPanel
-          key={selectedTenantId}
-          open={createAgentOpen}
-          onOpenChange={setCreateAgentOpen}
-          tenantId={selectedTenantId}
-          onCreated={(deployment) => {
-            if (currentTenantIdRef.current !== selectedTenantId) return;
-            void getAgentRun(selectedTenantId, deployment.id).then((run) => {
-              if (currentTenantIdRef.current !== selectedTenantId) return;
-              queryClient.setQueryData<Awaited<ReturnType<typeof listTenantInvitableDefinitions>>>(
-                ["tenant", selectedTenantId, "invitable-definitions"],
-                (current) => [
-                  ...(current ?? []).filter((agent) => agent.id !== run.definitionId),
-                  { id: run.definitionId, name: run.definitionName },
-                ],
-              );
-              setSelectedAgentDefinitionIds((current) => [...current, run.definitionId]);
-            });
-            promptRef.current?.focus();
-          }}
-        />
-      ) : null}
     </div>
   );
 }
diff --git a/apps/web/src/pages/tools-page.tsx b/apps/web/src/pages/tools-page.tsx
index 97bedccea..178221fd5 100644
--- a/apps/web/src/pages/tools-page.tsx
+++ b/apps/web/src/pages/tools-page.tsx
@@ -21,7 +21,7 @@ import { Plugs } from "@/lib/icons";
 import { WorkbenchLoadingState } from "@/chat";
 import { useCallback, useEffect, useState } from "react";
 
-import { listCapabilityInventory, type CapabilityInventory } from "../chat/api";
+import { listCapabilityInventory, type CapabilityInventory } from "../agents-api";
 import { useBench } from "../bench-context";
 import { StageTopBar } from "../shell/stage-top-bar";
 
diff --git a/apps/web/src/pages/workbench-room-page.tsx b/apps/web/src/pages/workbench-room-page.tsx
new file mode 100644
index 000000000..a57212247
--- /dev/null
+++ b/apps/web/src/pages/workbench-room-page.tsx
@@ -0,0 +1,246 @@
+// A workbench is a child tenant, and its room is that tenant's mailbox:
+// the timeline is the tenant's mail threads, participants are its
+// principals, and a message is addressed to every agent in the room.
+// Sub-threads are native in-reply-to chains, shown in a side panel.
+
+import { Button, EmptyState, PageShell, Textarea } from "@corbits/react-ui";
+import { WarningCircle } from "@/lib/icons";
+import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+import { useEffect, useState } from "react";
+
+import { Markdown } from "@/chat/markdown";
+import {
+  agentInitials,
+  listRoomParticipants,
+  readRoom,
+  sendToRoom,
+  subscribeToInbox,
+  type RoomMessage,
+  type RoomParticipant,
+} from "@/chat/threads-api";
+import { useBench } from "../bench-context";
+import { createFetchStockHub } from "../needs-converge";
+import { roomKeys } from "../chat-path";
+import { StageTopBar } from "../shell/stage-top-bar";
+import { workbenchIdFromPath } from "../workbench-path";
+
+function errorText(cause: unknown): string {
+  return cause instanceof Error ? cause.message : String(cause);
+}
+
+function RoomComposer({
+  placeholder,
+  busy,
+  onSend,
+}: {
+  readonly placeholder: string;
+  readonly busy: boolean;
+  readonly onSend: (text: string) => void;
+}) {
+  const [text, setText] = useState("");
+  const send = () => {
+    const trimmed = text.trim();
+    if (trimmed === "" || busy) return;
+    setText("");
+    onSend(trimmed);
+  };
+  return (
+    <div className="chat-composer">
+      <Textarea
+        value={text}
+        rows={3}
+        placeholder={placeholder}
+        aria-label={placeholder}
+        onChange={(event) => setText(event.target.value)}
+        onKeyDown={(event) => {
+          if (event.key === "Enter" && !event.shiftKey) {
+            event.preventDefault();
+            send();
+          }
+        }}
+      />
+      <Button variant="primary" disabled={busy || text.trim() === ""} onClick={send}>
+        {busy ? "Sending…" : "Send"}
+      </Button>
+    </div>
+  );
+}
+
+function RoomMessageRow({
+  message,
+  onOpenReplies,
+}: {
+  readonly message: RoomMessage;
+  readonly onOpenReplies: (message: RoomMessage) => void;
+}) {
+  return (
+    <div className="chat-thread-message" data-author={message.author}>
+      <span className="shell-ch-avatar">
+        <span className="shell-ch-initial" aria-hidden="true">
+          {message.author === "me" ? "You" : agentInitials(message.authorName)}
+        </span>
+      </span>
+      <div className="chat-thread-body">
+        <Markdown text={message.body} />
+        {message.replies.length === 0 ? null : (
+          <button
+            type="button"
+            className="room-replies-link"
+            onClick={() => onOpenReplies(message)}
+          >
+            {message.replies.length === 1 ? "1 reply" : `${String(message.replies.length)} replies`}
+          </button>
+        )}
+      </div>
+    </div>
+  );
+}
+
+function ParticipantList({ participants }: { readonly participants: readonly RoomParticipant[] }) {
+  return (
+    <ul className="room-participants" aria-label="In this workbench">
+      {participants.map((participant) => (
+        <li key={participant.id} data-kind={participant.kind}>
+          <span className="shell-ch-avatar">
+            <span className="shell-ch-initial" aria-hidden="true">
+              {agentInitials(participant.name)}
+            </span>
+          </span>
+          {participant.name}
+        </li>
+      ))}
+    </ul>
+  );
+}
+
+function Room({ roomTenantId }: { readonly roomTenantId: string }) {
+  const queryClient = useQueryClient();
+  const [openThread, setOpenThread] = useState<string | null>(null);
+
+  const tenant = useQuery({
+    queryKey: roomKeys.tenant(roomTenantId),
+    queryFn: () => createFetchStockHub().getTenant(roomTenantId),
+  });
+  const participants = useQuery({
+    queryKey: roomKeys.participants(roomTenantId),
+    queryFn: () => listRoomParticipants(roomTenantId),
+  });
+  const timeline = useQuery({
+    queryKey: roomKeys.timeline(roomTenantId),
+    queryFn: () => readRoom(roomTenantId),
+  });
+
+  // The room mailbox stream is the only signal that an agent answered; it
+  // carries no thread identity, so it invalidates rather than patches.
+  useEffect(
+    () =>
+      subscribeToInbox(roomTenantId, () => {
+        void queryClient.invalidateQueries({ queryKey: roomKeys.scope(roomTenantId) });
+      }),
+    [roomTenantId, queryClient],
+  );
+
+  const agents = (participants.data ?? []).filter((participant) => participant.kind === "agent");
+  const send = useMutation({
+    mutationFn: ({
+      content,
+      inReplyTo,
+    }: {
+      readonly content: string;
+      readonly inReplyTo?: string;
+    }) =>
+      sendToRoom({
+        roomTenantId,
+        agents,
+        content,
+        ...(inReplyTo !== undefined ? { inReplyTo } : {}),
+      }),
+    onSuccess: () => queryClient.invalidateQueries({ queryKey: roomKeys.scope(roomTenantId) }),
+  });
+
+  const messages = timeline.data ?? [];
+  const opened = messages.find((message) => message.id === openThread);
+  const failure: unknown = timeline.error ?? participants.error;
+
+  if (failure !== null && failure !== undefined && timeline.data === undefined) {
+    return (
+      <PageShell width="full" className="page-fill">
+        <EmptyState
+          icon={<WarningCircle />}
+          title="Couldn't open this workbench"
+          description={errorText(failure)}
+        />
+      </PageShell>
+    );
+  }
+
+  return (
+    <div className="flex h-full min-h-0 flex-col">
+      <StageTopBar crumbs={[{ label: tenant.data?.name ?? "Workbench" }]} />
+      <div className="room-layout">
+        <PageShell width="prose" className="page-fill">
+          <ParticipantList participants={participants.data ?? []} />
+          <div className="chat-thread-messages">
+            {messages.map((message) => (
+              <RoomMessageRow
+                key={message.id}
+                message={message}
+                onOpenReplies={(target) => setOpenThread(target.id)}
+              />
+            ))}
+          </div>
+          {send.error === null ? null : (
+            <p className="chat-thread-error">{errorText(send.error)}</p>
+          )}
+          <RoomComposer
+            placeholder="Message this workbench"
+            busy={send.isPending}
+            onSend={(text) => send.mutate({ content: text })}
+          />
+        </PageShell>
+        {opened === undefined ? null : (
+          <aside className="room-subthread" aria-label="Replies">
+            <div className="room-subthread-head">
+              <h2>Replies</h2>
+              <Button variant="ghost" size="sm" onClick={() => setOpenThread(null)}>
+                Close
+              </Button>
+            </div>
+            <div className="chat-thread-messages">
+              {[opened, ...opened.replies].map((message) => (
+                <RoomMessageRow
+                  key={message.id}
+                  message={message}
+                  onOpenReplies={() => undefined}
+                />
+              ))}
+            </div>
+            <RoomComposer
+              placeholder="Reply in this thread"
+              busy={send.isPending}
+              onSend={(text) => send.mutate({ content: text, inReplyTo: opened.messageId })}
+            />
+          </aside>
+        )}
+      </div>
+    </div>
+  );
+}
+
+export function WorkbenchRoomRoute({ path }: { readonly path: string }) {
+  const { selectedTenantId } = useBench();
+  const roomTenantId = workbenchIdFromPath(path);
+
+  if (selectedTenantId === null || roomTenantId === null) {
+    return (
+      <PageShell width="full" className="page-fill">
+        <EmptyState
+          icon={<WarningCircle />}
+          title="No workbench selected"
+          description="Pick a workbench from the sidebar, or start a new one."
+        />
+      </PageShell>
+    );
+  }
+  return <Room roomTenantId={roomTenantId} />;
+}
diff --git a/apps/web/src/pages/workbench-timeline.tsx b/apps/web/src/pages/workbench-timeline.tsx
deleted file mode 100644
index 016fa5239..000000000
--- a/apps/web/src/pages/workbench-timeline.tsx
+++ /dev/null
@@ -1,250 +0,0 @@
-// Per-workbench Insights view: one wall-clock spine merging chat
-// messages, thread forks, and approvals for a single workbench
-// (== workbench, per docs/GLOSSARY.md), oldest to newest with day dividers.
-// No new backend — every fetch here is an existing route this app already
-// reads elsewhere (chat-ui, api.ts); the new work is
-// `../workbench-timeline-merge.ts`'s pure merge, plus this render.
-
-import { Badge, RichEmptyState, Skeleton } from "@corbits/react-ui";
-import { listMessages, listThreads } from "@/chat";
-import { Clock } from "@/lib/icons";
-import { useMemo, useState } from "react";
-
-import { usePendingApprovals } from "../pending-approvals";
-import { useTenantQuery } from "../routines-api";
-import { tenantKeys } from "../query-client";
-import {
-  computeTimelineDayKpis,
-  filterTimelineEvents,
-  groupTimelineByDay,
-  mergeTimelineEvents,
-  toApprovalEvents,
-  toMessageEvents,
-  toThreadForkEvents,
-  type TimelineEvent,
-  type TimelineFilter,
-} from "../workbench-timeline-merge";
-
-const FILTERS: readonly {
-  readonly id: TimelineFilter;
-  readonly label: string;
-}[] = [
-  { id: "all", label: "All" },
-  { id: "messages", label: "Messages" },
-  { id: "approvals", label: "Approvals" },
-];
-
-function timeOfDay(iso: string): string {
-  const date = new Date(iso);
-  if (Number.isNaN(date.getTime())) return "—";
-  return date.toLocaleTimeString(undefined, {
-    hour: "numeric",
-    minute: "2-digit",
-  });
-}
-
-function markerClass(event: TimelineEvent): string {
-  switch (event.kind) {
-    case "message":
-      return event.isAgent
-        ? "workbench-timeline-marker-primary"
-        : "workbench-timeline-marker-neutral";
-    case "thread-fork":
-      return "workbench-timeline-marker-neutral";
-    case "approval":
-      return "workbench-timeline-marker-warn";
-  }
-}
-
-function TimelineRowBody({ event }: { readonly event: TimelineEvent }) {
-  switch (event.kind) {
-    case "message":
-      return (
-        <div className="workbench-timeline-entry-body">
-          <strong>{event.senderName}</strong>
-          <span className="workbench-timeline-entry-excerpt">{event.excerpt}</span>
-        </div>
-      );
-    case "thread-fork":
-      return (
-        <div className="workbench-timeline-entry-body">
-          <span>
-            Forked {event.threadKind === "delivery" ? "delivery" : "reply"} thread · {event.title}
-          </span>
-        </div>
-      );
-    case "approval":
-      return (
-        <div className="workbench-timeline-entry-body">
-          <span>
-            {event.agentName} needs your approval · {event.headline}
-          </span>
-          <Badge tone="warning">pending</Badge>
-        </div>
-      );
-  }
-}
-
-function TimelineRow({ event }: { readonly event: TimelineEvent }) {
-  const indented = event.kind === "thread-fork";
-  return (
-    <li
-      className="workbench-timeline-entry"
-      data-indented={indented}
-      data-ctx-timeline-event={event.id}
-    >
-      <span className={`workbench-timeline-marker ${markerClass(event)}`} aria-hidden="true" />
-      <span className="workbench-timeline-entry-time">{timeOfDay(event.at)}</span>
-      <TimelineRowBody event={event} />
-    </li>
-  );
-}
-
-function DayKpiRow({ kpi }: { readonly kpi: ReturnType<typeof computeTimelineDayKpis>[number] }) {
-  return (
-    <div className="workbench-timeline-kpi-day">
-      <h4>{kpi.label}</h4>
-      <dl>
-        <div>
-          <dt>Messages</dt>
-          <dd>{kpi.messages}</dd>
-        </div>
-        <div>
-          <dt>Agent turns</dt>
-          <dd>{kpi.agentTurns}</dd>
-        </div>
-        <div>
-          <dt>Approvals</dt>
-          <dd>{kpi.approvals}</dd>
-        </div>
-      </dl>
-    </div>
-  );
-}
-
-export function WorkbenchTimelineView({
-  events,
-  loading,
-}: {
-  readonly events: readonly TimelineEvent[];
-  readonly loading: boolean;
-}) {
-  const [filter, setFilter] = useState<TimelineFilter>("all");
-  const filtered = useMemo(() => filterTimelineEvents(events, filter), [events, filter]);
-  const dayGroups = useMemo(() => groupTimelineByDay(filtered), [filtered]);
-  const kpis = useMemo(() => computeTimelineDayKpis(events), [events]);
-
-  if (loading) {
-    return <Skeleton className="h-48 w-full" />;
-  }
-
-  if (events.length === 0) {
-    return (
-      <RichEmptyState
-        icon={<Clock />}
-        title="Nothing on this workbench's timeline yet"
-        description="Messages and approvals will show up here as they happen."
-      />
-    );
-  }
-
-  return (
-    <div className="workbench-timeline">
-      <div className="workbench-timeline-filters" role="group" aria-label="Timeline filter">
-        {FILTERS.map((option) => (
-          <button
-            key={option.id}
-            type="button"
-            aria-pressed={filter === option.id}
-            data-active={filter === option.id}
-            className="workbench-timeline-filter-option"
-            onClick={() => setFilter(option.id)}
-          >
-            {option.label}
-          </button>
-        ))}
-      </div>
-      <div className="workbench-timeline-body">
-        <div className="workbench-timeline-spine">
-          {dayGroups.length === 0 ? (
-            <p className="insights-note">No events match this filter.</p>
-          ) : (
-            dayGroups.map((day) => (
-              <section key={day.day} className="workbench-timeline-day">
-                <div className="workbench-timeline-day-divider">
-                  <span>{day.label}</span>
-                </div>
-                <ol className="workbench-timeline-rail">
-                  {day.events.map((event) => (
-                    <TimelineRow key={`${event.kind}-${event.id}`} event={event} />
-                  ))}
-                </ol>
-              </section>
-            ))
-          )}
-        </div>
-        <aside className="workbench-timeline-kpis">
-          <h3>Daily activity</h3>
-          {kpis.map((kpi) => (
-            <DayKpiRow key={kpi.day} kpi={kpi} />
-          ))}
-        </aside>
-      </div>
-    </div>
-  );
-}
-
-/**
- * Fetch composition for one workbench's Timeline. `benchTenantId` is the
- * owning bench — chat's own workbench-tenancy keeps messages/threads
- * addressed at the parent bench's tenant id even though the workbench also
- * mints its own workbench tenant (see docs/workbench-tenancy.md) — while
- * `workbenchId` is the workbench's own id, resolved to that workbench tenant
- * one level up in `InsightsWorkbenchPage` (`../insights-workbench-scope.ts`)
- * for the tenant-scoped Insights endpoints; this component only ever reads
- * messages/threads/approvals off the owning bench.
- */
-export function WorkbenchTimelineRoute({
-  benchTenantId,
-  workbenchId,
-}: {
-  readonly benchTenantId: string | null;
-  readonly workbenchId: string;
-  readonly onOpenRun: (runId: string) => void;
-}) {
-  const messagesQuery = useTenantQuery(
-    benchTenantId === null
-      ? ["tenant", "none", "chat", "workbenches", workbenchId, "messages"]
-      : tenantKeys.workbenchMessages(benchTenantId, workbenchId),
-    benchTenantId !== null,
-    () => listMessages(benchTenantId as string, workbenchId).then((page) => page.items),
-  );
-  const threadsQuery = useTenantQuery(
-    benchTenantId === null
-      ? ["tenant", "none", "chat", "workbenches", workbenchId, "threads"]
-      : tenantKeys.workbenchThreads(benchTenantId, workbenchId),
-    benchTenantId !== null,
-    () => listThreads(benchTenantId as string, workbenchId).then((page) => page.items),
-  );
-  const approvalsQuery = usePendingApprovals(benchTenantId);
-
-  const loading =
-    messagesQuery.kind === "loading" ||
-    threadsQuery.kind === "loading" ||
-    approvalsQuery.kind === "loading";
-
-  const messages = messagesQuery.kind === "ready" ? messagesQuery.data : [];
-  const threads = threadsQuery.kind === "ready" ? threadsQuery.data : [];
-  // An approval carries no workbench id (a known v1 gap — see
-  // workbench-timeline-merge.ts's toApprovalEvents), so this is every
-  // pending approval on the owning bench, not just this workbench's own.
-  const approvals = approvalsQuery.kind === "ready" ? approvalsQuery.data : [];
-
-  const events = mergeTimelineEvents({
-    messages: toMessageEvents(messages),
-    threadForks: toThreadForkEvents(threads),
-    approvals: toApprovalEvents(approvals),
-  });
-
-  return <WorkbenchTimelineView events={events} loading={loading} />;
-}
diff --git a/apps/web/src/profile-relations.test.ts b/apps/web/src/profile-relations.test.ts
deleted file mode 100644
index 3a8c2d73e..000000000
--- a/apps/web/src/profile-relations.test.ts
+++ /dev/null
@@ -1,48 +0,0 @@
-import { describe, expect, test } from "bun:test";
-import type { ProfileSubject } from "@/chat";
-
-import { dmCreateInputFor } from "./profile-relations";
-
-function subject(overrides: Partial<ProfileSubject>): ProfileSubject {
-  return {
-    kind: "member",
-    address: "usr_alice@bench.dev",
-    handle: "alice",
-    displayName: "Alice",
-    initials: "AL",
-    ...overrides,
-  };
-}
-
-describe("dmCreateInputFor", () => {
-  test("a person subject creates a chat by principalId, derived from the address local part", () => {
-    const input = dmCreateInputFor(subject({}), null);
-    expect(input).toEqual({
-      kind: "chat",
-      principalId: "usr_alice",
-      name: "Alice",
-    });
-  });
-
-  test("an agent subject creates a chat by the definitionId of its running instance", () => {
-    const input = dmCreateInputFor(
-      subject({
-        kind: "agent",
-        address: "ins_42@bench.dev",
-        handle: "myra",
-        displayName: "@myra",
-      }),
-      "def_myra",
-    );
-    expect(input).toEqual({
-      kind: "chat",
-      definitionId: "def_myra",
-      name: "@myra",
-    });
-  });
-
-  test("an agent subject with no matching running instance has no create input", () => {
-    const input = dmCreateInputFor(subject({ kind: "agent", address: "ins_42@bench.dev" }), null);
-    expect(input).toBeNull();
-  });
-});
diff --git a/apps/web/src/profile-relations.ts b/apps/web/src/profile-relations.ts
deleted file mode 100644
index 2a56250f2..000000000
--- a/apps/web/src/profile-relations.ts
+++ /dev/null
@@ -1,106 +0,0 @@
-// What the profile card's Message action and shared-workbenches list need,
-// resolved against real bench data. Generalizes
-// `myra-workbench.ts`'s ensure-style reuse — find an existing 1:1 by
-// participant instead of by a fixed title, and fall back to creating one —
-// to any profile subject rather than one hardcoded agent.
-
-import { localPartOf } from "@/chat/wire/agent-address";
-import {
-  createWorkbench,
-  findDirectWorkbenchWith,
-  listWorkbenches,
-  sharedWorkbenchesWith,
-  type CreateWorkbenchInput,
-  type ProfileSubject,
-  type SharedWorkbenchSummary,
-} from "@/chat";
-
-import { listAgentInstances } from "./agents-api";
-
-export async function loadSharedWorkbenches(
-  tenantId: string,
-  viewerPrincipalId: string,
-  subject: ProfileSubject,
-): Promise<readonly SharedWorkbenchSummary[]> {
-  const [workbenches, chats] = await Promise.all([
-    listWorkbenches(tenantId, "workbench"),
-    listWorkbenches(tenantId, "chat"),
-  ]);
-  return sharedWorkbenchesWith([...workbenches, ...chats], viewerPrincipalId, subject.address);
-}
-
-/**
- * The chat `POST /workbenches` body for starting a 1:1 with `subject` — a
- * person's chat is keyed by principalId (the address local part, per
- * `timeline.tsx`'s `CurrentUser` doc comment); an agent's chat is keyed by
- * the definitionId of whichever running instance owns `subject.address`,
- * which the caller resolves via `listAgentInstances` and passes in as
- * `agentDefinitionId`. `null` means no such running instance was found —
- * there is nothing honest to create a chat against.
- */
-export function dmCreateInputFor(
-  subject: ProfileSubject,
-  agentDefinitionId: string | null,
-): CreateWorkbenchInput | null {
-  if (subject.kind === "agent") {
-    if (agentDefinitionId === null) return null;
-    return {
-      kind: "chat",
-      definitionId: agentDefinitionId,
-      name: subject.displayName,
-    };
-  }
-  return {
-    kind: "chat",
-    principalId: localPartOf(subject.address),
-    name: subject.displayName,
-  };
-}
-
-export type EnsureProfileDmResult =
-  | { readonly kind: "ready"; readonly workbenchId: string }
-  | { readonly kind: "error"; readonly message: string };
-
-/**
- * Open-or-create the direct workbench with `subject`: reuse a chat or
- * workbench `subject.address` already participates in, else create a fresh
- * chat.
- */
-export async function ensureProfileDm(
-  tenantId: string,
-  subject: ProfileSubject,
-): Promise<EnsureProfileDmResult> {
-  try {
-    const [workbenches, chats] = await Promise.all([
-      listWorkbenches(tenantId, "workbench"),
-      listWorkbenches(tenantId, "chat"),
-    ]);
-    const existing =
-      findDirectWorkbenchWith(chats, subject.address) ??
-      findDirectWorkbenchWith(workbenches, subject.address);
-    if (existing !== undefined) {
-      return { kind: "ready", workbenchId: existing.id };
-    }
-
-    let agentDefinitionId: string | null = null;
-    if (subject.kind === "agent") {
-      const instances = await listAgentInstances(tenantId);
-      const instance = instances.find((candidate) => candidate.address === subject.address);
-      agentDefinitionId = instance?.definitionId ?? null;
-    }
-    const input = dmCreateInputFor(subject, agentDefinitionId);
-    if (input === null) {
-      return {
-        kind: "error",
-        message: `No running agent found for @${subject.handle}.`,
-      };
-    }
-    const created = await createWorkbench(tenantId, input);
-    return { kind: "ready", workbenchId: created.id };
-  } catch (cause) {
-    return {
-      kind: "error",
-      message: cause instanceof Error ? cause.message : String(cause),
-    };
-  }
-}
diff --git a/apps/web/src/query-client.ts b/apps/web/src/query-client.ts
index 3775e7736..0bb5e98fd 100644
--- a/apps/web/src/query-client.ts
+++ b/apps/web/src/query-client.ts
@@ -5,8 +5,8 @@
 import { MutationCache, QueryCache, QueryClient } from "@tanstack/react-query";
 
 import { ApiQueryError, UnauthenticatedError } from "@/lib/api-query";
-import { workbenchesQueryKey } from "@/chat";
-import type { WorkbenchKind } from "@/chat";
+import { workbenchesQueryKey } from "@/chat/workbench-tenants";
+import type { WorkbenchKind } from "@/chat/workbench-tenants";
 
 /**
  * Retry policy shared by every query in the app: no session and a
diff --git a/apps/web/src/routes.tsx b/apps/web/src/routes.tsx
index bbeebacb0..4e575e8c4 100644
--- a/apps/web/src/routes.tsx
+++ b/apps/web/src/routes.tsx
@@ -63,8 +63,8 @@ const MissionControlRoute = lazy(async () => ({
 const NewWorkbenchPickerRoute = lazy(async () => ({
   default: (await import("./pages/new-workbench-picker")).NewWorkbenchPickerRoute,
 }));
-const ChatPage = lazy(async () => ({
-  default: (await import("./pages/chat-page")).ChatPage,
+const WorkbenchRoomRoute = lazy(async () => ({
+  default: (await import("./pages/workbench-room-page")).WorkbenchRoomRoute,
 }));
 const ChatThreadRoute = lazy(async () => ({
   default: (await import("./pages/chat-thread-page")).ChatThreadRoute,
@@ -275,9 +275,7 @@ export const APP_ROUTES: readonly AppRoute[] = [
     path: WORKBENCH_PATH_PREFIX,
     label: "Workbenches",
     icon: <ChatCircle />,
-    render: (path: string, navigate: (to: string) => void) => (
-      <ChatPage path={path} navigate={navigate} />
-    ),
+    render: (path: string) => <WorkbenchRoomRoute path={path} />,
   },
   {
     path: "/inbox",
diff --git a/apps/web/src/shell/bench-activity.ts b/apps/web/src/shell/bench-activity.ts
index 02b44b076..3e1fab446 100644
--- a/apps/web/src/shell/bench-activity.ts
+++ b/apps/web/src/shell/bench-activity.ts
@@ -1,30 +1,14 @@
-// The sidebar's one data source: everything happening in the currently
-// selected bench right now. Workbenches and chats come from
-// `@/chat`'s own validated fetches; running routines come through
-// the seam in `./routine-activity.ts`. Notifications have no backing
-// feature in the hub yet, so they are not fetched here at all — the
-// column renders an honest empty state for that section instead of a
-// query with nowhere to point.
-//
-// `useBenchActivity` may be mounted more than once per navigation (the
-// sidebar's `WorkbenchList` in `./workbench-list.tsx`), so every listing
-// below goes through `useQuery` keyed with the shared `tenantKeys`
-// factories — both mounts subscribe to the same cached queries instead of
-// each firing its own fetch. This uses `useQuery` directly rather than the
-// app's `useTenantQuery` wrapper because that wrapper's `toAPIQuery` maps a
-// failure onto generic copy; this band shows the real error text instead
-// (the mock's error states are diagnostic, not decorative).
+// Everything happening in the selected bench right now, over stock
+// listings only: workbenches are the bench's child tenants, chats are the
+// person's mail threads, agents are the bench's workflow definitions, and
+// running routines come through the seam in `./routine-activity.ts`.
+// Notifications have no backing feature in the hub, so nothing is fetched
+// for them — the column renders an honest empty state instead.
 
-import { useEffect } from "react";
-import { useQuery, useQueryClient } from "@tanstack/react-query";
-import {
-  WORKBENCHES_MUTATED_EVENT,
-  workbenchesQueryKeyPrefix,
-  listWorkbenches,
-  listVisibleAgentDefinitions,
-} from "@/chat";
-import type { Workbench, VisibleAgentDefinition } from "@/chat";
+import { useQuery } from "@tanstack/react-query";
+import { listWorkbenches, type Workbench } from "@/chat/workbench-tenants";
 
+import { listAgentDefinitions, type AgentDefinition } from "../agents-api";
 import { tenantKeys } from "../query-client";
 import { listRoutineActivity } from "./routine-activity";
 import type { RoutineActivityItem } from "./routine-activity";
@@ -37,7 +21,7 @@ export type BenchActivityQuery =
       readonly kind: "ready";
       readonly workbenches: readonly Workbench[];
       readonly chats: readonly Workbench[];
-      readonly agents: readonly VisibleAgentDefinition[];
+      readonly agents: readonly AgentDefinition[];
       readonly routines: readonly RoutineActivityItem[];
     };
 
@@ -45,29 +29,12 @@ function errorMessage(cause: unknown): string {
   return cause instanceof Error ? cause.message : String(cause);
 }
 
-/** Bench-scoped live activity for the second column, refetched whenever the
- * selected bench changes — nothing here is page-scoped, so a route change
- * alone never triggers a refetch. */
+/** Bench-scoped live activity for the second column, refetched whenever
+ * the selected bench changes — nothing here is page-scoped, so a route
+ * change alone never triggers a refetch. */
 export function useBenchActivity(tenantId: string | null): BenchActivityQuery {
   const enabled = tenantId !== null;
   const key = tenantId ?? "";
-  const queryClient = useQueryClient();
-
-  // A conversation minted anywhere (picker dialog, agent launch, the
-  // land-hop) announces itself via `WORKBENCHES_MUTATED_EVENT`; without
-  // this, the sidebar's cached listing only catches up on the next
-  // unrelated refetch and a fresh workbench is invisible until then.
-  useEffect(() => {
-    const onMutated = (event: Event) => {
-      const detail = (event as CustomEvent<{ tenantId?: string }>).detail;
-      if (detail?.tenantId === undefined) return;
-      void queryClient.invalidateQueries({
-        queryKey: workbenchesQueryKeyPrefix(detail.tenantId),
-      });
-    };
-    window.addEventListener(WORKBENCHES_MUTATED_EVENT, onMutated);
-    return () => window.removeEventListener(WORKBENCHES_MUTATED_EVENT, onMutated);
-  }, [queryClient]);
 
   const workbenchesQuery = useQuery({
     queryKey: tenantKeys.workbenches(key, "workbench"),
@@ -82,18 +49,12 @@ export function useBenchActivity(tenantId: string | null): BenchActivityQuery {
   const routinesQuery = useQuery({
     queryKey: tenantKeys.routineActivity(key),
     enabled,
-    // `listRoutineActivity` resolves no items without fetching
-    // (the `feed=fires` route is deleted and the native listing has no
-    // fires equivalent), so this query never fires a request — the
-    // column keeps the shared key and renders the seam's honest empty
-    // state. Rewire `listRoutineActivity` (not this key) when a native
-    // fires equivalent exists.
     queryFn: () => listRoutineActivity(),
   });
   const agentsQuery = useQuery({
     queryKey: tenantKeys.visibleAgents(key),
     enabled,
-    queryFn: () => listVisibleAgentDefinitions(key),
+    queryFn: () => listAgentDefinitions(key),
   });
 
   if (tenantId === null) return { kind: "empty" };
diff --git a/apps/web/src/shell/canvas-column.tsx b/apps/web/src/shell/canvas-column.tsx
index 775c2f23d..729cf52e9 100644
--- a/apps/web/src/shell/canvas-column.tsx
+++ b/apps/web/src/shell/canvas-column.tsx
@@ -30,14 +30,12 @@ import {
   type ProfileCardChannel,
 } from "@corbits/react-ui";
 import { ArtifactRenderer, ArtifactTextEditor, type ArtifactSaveState } from "@/library";
-import type { ProfileSubject, SharedWorkbenchSummary } from "@/chat";
+import type { ProfileSubject } from "@/chat";
 import { ArrowsIn, ArrowsOut, ArrowSquareOut, CaretLeft, UserCircle, X } from "@/lib/icons";
-import { useEffect, useState } from "react";
 import type { ReactNode } from "react";
 
 import { useBench } from "../bench-context";
-import { workbenchPath } from "../workbench-path";
-import { ensureProfileDm, loadSharedWorkbenches } from "../profile-relations";
+import { NEW_CHAT_PATH } from "../chat-path";
 import type { CanvasArtifactContent, RoutinePanelSubject } from "./canvas-availability";
 import { useInsertIntoComposer } from "./composer-insertion";
 
@@ -103,36 +101,22 @@ export function CanvasColumn({
   );
 }
 
-/**
- * Open-or-create the DM with `profile` and land on it. `tenantId === null`
- * (bench not resolved yet) has nothing to message against — an honest toast,
- * matching `mentionAction`'s pattern, rather than a silent no-op. The panel
- * only closes once the DM is actually resolved: `setPending` drives the
- * button's in-flight label so a slow create isn't mistaken for nothing
- * having happened.
- */
+/** Messaging someone is composing a chat thread with them: land on the
+ * composer rather than minting anything here. */
 function messageAction(
   tenantId: string | null,
   profile: ProfileSubject,
   onNavigate: (path: string) => void,
   onClose: () => void,
-  setPending: (pending: boolean) => void,
 ): () => void {
   return () => {
     if (tenantId === null) {
       toast(`Open a workbench to message @${profile.handle}`);
       return;
     }
-    setPending(true);
-    void ensureProfileDm(tenantId, profile).then((result) => {
-      setPending(false);
-      if (result.kind === "ready") {
-        onNavigate(workbenchPath(result.workbenchId));
-        onClose();
-      } else {
-        toast(result.message);
-      }
-    });
+    // A DM is a chat thread now: compose it on /chats/new.
+    onNavigate(NEW_CHAT_PATH);
+    onClose();
   };
 }
 
@@ -239,14 +223,12 @@ function profileActions(
   onClose: () => void,
   onNavigate: (path: string) => void,
   insertIntoComposer: (text: string) => boolean,
-  messagePending: boolean,
-  setMessagePending: (pending: boolean) => void,
 ): readonly ProfileCardAction[] {
   const message: ProfileCardAction = {
     id: "message",
-    label: messagePending ? "Messaging…" : "Message",
+    label: "Message",
     tone: "primary",
-    onClick: messageAction(tenantId, profile, onNavigate, onClose, setMessagePending),
+    onClick: messageAction(tenantId, profile, onNavigate, onClose),
   };
   const mention: ProfileCardAction = {
     id: "mention",
@@ -303,46 +285,10 @@ function profileActions(
   ];
 }
 
-function toProfileCardWorkbenches(
-  workbenches: readonly SharedWorkbenchSummary[],
-): readonly ProfileCardChannel[] {
-  return workbenches.map((workbench) => ({
-    id: workbench.id,
-    name: workbench.title,
-    href: workbenchPath(workbench.id),
-  }));
-}
-
-/** Shared workbenches between the viewer and `profile` — refetched
- * whenever the open profile changes, dropped if a later change races past
- * an in-flight fetch. Pinned skills are intentionally never populated: no
- * agent carries any real skill-attachment data yet (tracked in), so
- * showing them would be fabricated, not deferred. */
-function useSharedWorkbenches(
-  tenantId: string | null,
-  viewerPrincipalId: string | null,
-  profile: ProfileSubject,
-): readonly SharedWorkbenchSummary[] {
-  const [workbenches, setWorkbenches] = useState<readonly SharedWorkbenchSummary[]>([]);
-
-  useEffect(() => {
-    setWorkbenches([]);
-    if (tenantId === null || viewerPrincipalId === null) return;
-    let cancelled = false;
-    void loadSharedWorkbenches(tenantId, viewerPrincipalId, profile).then(
-      (result) => {
-        if (!cancelled) setWorkbenches(result);
-      },
-      () => {
-        if (!cancelled) setWorkbenches([]);
-      },
-    );
-    return () => {
-      cancelled = true;
-    };
-  }, [tenantId, viewerPrincipalId, profile.address]);
-
-  return workbenches;
+/** Shared workbenches are not listed: membership of another principal in
+ * a room has no stock read, so the card shows none rather than guessing. */
+function useSharedWorkbenches(): readonly ProfileCardChannel[] {
+  return [];
 }
 
 function ProfileCanvasPane({
@@ -358,14 +304,9 @@ function ProfileCanvasPane({
   readonly onToggleFocus: () => void;
   readonly onNavigate: (path: string) => void;
 }) {
-  const { selectedTenantId, selectedPrincipalId } = useBench();
+  const { selectedTenantId } = useBench();
   const insertIntoComposer = useInsertIntoComposer();
-  const [messagePending, setMessagePending] = useState(false);
-  // A new subject means any in-flight "Messaging…" belonged to the last one.
-  useEffect(() => {
-    setMessagePending(false);
-  }, [profile.address]);
-  const sharedWorkbenches = useSharedWorkbenches(selectedTenantId, selectedPrincipalId, profile);
+  const sharedWorkbenches = useSharedWorkbenches();
 
   return (
     <div className="shell-profile-pane">
@@ -376,16 +317,8 @@ function ProfileCanvasPane({
         initials={profile.initials}
         statusLabel={profile.kind === "agent" ? "Agent" : "Member"}
         avatarTone={profile.kind === "agent" ? "agent" : "neutral"}
-        actions={profileActions(
-          profile,
-          selectedTenantId,
-          onClose,
-          onNavigate,
-          insertIntoComposer,
-          messagePending,
-          setMessagePending,
-        )}
-        sharedChannels={toProfileCardWorkbenches(sharedWorkbenches)}
+        actions={profileActions(profile, selectedTenantId, onClose, onNavigate, insertIntoComposer)}
+        sharedChannels={sharedWorkbenches}
       />
     </div>
   );
diff --git a/apps/web/src/shell/context-menu/items.test.tsx b/apps/web/src/shell/context-menu/items.test.tsx
deleted file mode 100644
index 26deee27b..000000000
--- a/apps/web/src/shell/context-menu/items.test.tsx
+++ /dev/null
@@ -1,298 +0,0 @@
-import { beforeEach, describe, expect, mock, spyOn, test } from "bun:test";
-
-import { spyOnReactUiToast } from "../../react-ui-toast-mock";
-import type { ContextMenuEntry } from "@/shell/context-menu/lib";
-import { WORKBENCHES_MUTATED_EVENT } from "@/chat";
-import * as errorSink from "@corbits/error-sink";
-
-const toastMock = spyOnReactUiToast();
-
-import { shellContextMenuFor } from "./items";
-import type { ShellContextMenuActions } from "./items";
-import type { ShellContextMenuTarget } from "./targets";
-import { LIBRARY_BULK_OPERATION_IDS } from "../library-artifacts";
-
-function itemIds(entries: readonly ContextMenuEntry[]): readonly string[] {
-  return entries
-    .filter((entry): entry is Extract<ContextMenuEntry, { kind: "item" }> => entry.kind === "item")
-    .map((entry) => entry.id);
-}
-
-function findItem(entries: readonly ContextMenuEntry[], id: string) {
-  const entry = entries.find((candidate) => candidate.kind === "item" && candidate.id === id);
-  if (entry === undefined || entry.kind !== "item") {
-    throw new Error(`no item "${id}" in menu`);
-  }
-  return entry;
-}
-
-function actions(overrides: Partial<ShellContextMenuActions> = {}): ShellContextMenuActions {
-  return {
-    tenantId: "tenant-1",
-    navigate: mock(() => undefined),
-    openProfile: mock(() => undefined),
-    cycleTheme: mock(() => undefined),
-    signOut: mock(() => undefined),
-    onRoutineRan: mock((_tenantId: string) => undefined),
-    ...overrides,
-  };
-}
-
-beforeEach(() => {
-  Object.defineProperty(navigator, "clipboard", {
-    configurable: true,
-    value: { writeText: mock(() => Promise.resolve()) },
-  });
-  toastMock.mockClear();
-});
-
-describe("shellContextMenuFor: workbench", () => {
-  const target: ShellContextMenuTarget = {
-    type: "workbench",
-    id: "ch-1",
-    title: "Launch Planning",
-    pinned: false,
-  };
-
-  test("offers rename, pin, and copy-link with a tenant selected", () => {
-    const menu = shellContextMenuFor(target, actions());
-    expect(itemIds(menu.entries)).toEqual(["rename", "pin", "copy-link"]);
-    expect(findItem(menu.entries, "pin").label).toBe("Pin workbench");
-  });
-
-  test("labels the pin item Unpin for an already-pinned workbench", () => {
-    const menu = shellContextMenuFor({ ...target, pinned: true }, actions());
-    expect(findItem(menu.entries, "pin").label).toBe("Unpin workbench");
-  });
-
-  test("drops the pin item without a selected tenant", () => {
-    const menu = shellContextMenuFor(target, actions({ tenantId: null }));
-    expect(itemIds(menu.entries)).toEqual(["rename", "copy-link"]);
-  });
-
-  test("pin dispatches WORKBENCHES_MUTATED_EVENT so the sidebar list refetches", async () => {
-    const realFetch = globalThis.fetch;
-    // `patchWorkbenchSettings` validates against WorkbenchSettingsResponse —
-    // a partial body rejects and the success path (event + toast) never runs.
-    globalThis.fetch = mock(() =>
-      Promise.resolve(
-        new Response(
-          JSON.stringify({
-            id: "ch-1",
-            title: "Launch Planning",
-            kind: "workbench",
-            pinned: true,
-            participants: [],
-            settings: { "chat/pinned": true },
-            contextWindow: { value: 0, source: "inherit" },
-          }),
-          { status: 200, headers: { "content-type": "application/json" } },
-        ),
-      ),
-    ) as unknown as typeof fetch;
-    const events: Event[] = [];
-    const listener = (event: Event) => events.push(event);
-    window.addEventListener(WORKBENCHES_MUTATED_EVENT, listener);
-    try {
-      const menu = shellContextMenuFor(target, actions());
-      findItem(menu.entries, "pin").onSelect();
-      // request() awaits fetch then response.json() before the success
-      // .then (event + toast) runs — a few microtasks alone fall short.
-      for (let i = 0; i < 10 && events.length === 0; i++) {
-        await Promise.resolve();
-      }
-      if (events.length === 0) {
-        await new Promise((resolve) => setTimeout(resolve, 0));
-      }
-      expect(events).toHaveLength(1);
-      expect((events[0] as CustomEvent<{ tenantId: string }>).detail).toEqual({
-        tenantId: "tenant-1",
-      });
-      expect(toastMock).toHaveBeenCalledWith("Workbench pinned");
-    } finally {
-      window.removeEventListener(WORKBENCHES_MUTATED_EVENT, listener);
-      globalThis.fetch = realFetch;
-    }
-  });
-
-  test("copy-link writes the workbench's canonical URL to the clipboard", async () => {
-    const menu = shellContextMenuFor(target, actions());
-    findItem(menu.entries, "copy-link").onSelect();
-    await Promise.resolve();
-    expect(navigator.clipboard.writeText).toHaveBeenCalledWith(`${window.location.origin}/w/ch-1`);
-    expect(toastMock).toHaveBeenCalledWith("Launch Planning link copied");
-  });
-
-  test("copy-link surfaces a toast instead of throwing when the clipboard write fails", async () => {
-    Object.defineProperty(navigator, "clipboard", {
-      configurable: true,
-      value: { writeText: mock(() => Promise.reject(new Error("denied"))) },
-    });
-    const menu = shellContextMenuFor(target, actions());
-
-    expect(() => findItem(menu.entries, "copy-link").onSelect()).not.toThrow();
-    await Promise.resolve();
-    await Promise.resolve();
-
-    expect(toastMock).toHaveBeenCalledWith("Couldn't copy the link");
-  });
-});
-
-describe("shellContextMenuFor: profile", () => {
-  test("offers exactly one open-profile item", () => {
-    const target: ShellContextMenuTarget = {
-      type: "profile",
-      address: "agent:echo",
-      handle: "echo",
-    };
-    const openProfile = mock(() => undefined);
-    const menu = shellContextMenuFor(target, actions({ openProfile }));
-    expect(itemIds(menu.entries)).toEqual(["open-profile"]);
-    findItem(menu.entries, "open-profile").onSelect();
-    expect(openProfile).toHaveBeenCalledTimes(1);
-  });
-});
-
-describe("shellContextMenuFor: routine", () => {
-  const target: ShellContextMenuTarget = {
-    type: "routine",
-    id: "rt-1",
-    name: "Nightly Digest",
-  };
-
-  test("offers open, run-now, and copy-link with a tenant selected", () => {
-    const menu = shellContextMenuFor(target, actions());
-    expect(itemIds(menu.entries)).toEqual(["open", "run-now", "copy-link"]);
-  });
-
-  test("drops run-now without a selected tenant", () => {
-    const menu = shellContextMenuFor(target, actions({ tenantId: null }));
-    expect(itemIds(menu.entries)).toEqual(["open", "copy-link"]);
-  });
-
-  test("open navigates to the routine's canonical route", () => {
-    const navigate = mock((_to: string) => undefined);
-    const menu = shellContextMenuFor(target, actions({ navigate }));
-    findItem(menu.entries, "open").onSelect();
-    expect(navigate).toHaveBeenCalledWith("/workflows/rt-1");
-  });
-
-  // `runScheduledWorkflowNow` no longer calls a hub route at all
-  // (`@corbits/workflows`'s scheduled-workflow routes are deleted — see
-  // `apps/web/src/routines-api.ts`'s file header) — it always rejects. The
-  // former "run starts" success-path test asserted an outcome that is no
-  // longer reachable through any fetch response and is deleted rather
-  // than adapted; the failure path below still holds, just without a
-  // mocked fetch to drive it.
-  test("run-now surfaces a toast and reports the error, since it has no stock route yet", async () => {
-    const report = spyOn(errorSink, "reportError").mockReturnValue("ref_test");
-    const onRoutineRan = mock((_tenantId: string) => undefined);
-    try {
-      const menu = shellContextMenuFor(target, actions({ onRoutineRan }));
-      findItem(menu.entries, "run-now").onSelect();
-      for (let i = 0; i < 10 && toastMock.mock.calls.length === 0; i++) {
-        await Promise.resolve();
-      }
-      expect(onRoutineRan).not.toHaveBeenCalled();
-      expect(report).toHaveBeenCalled();
-      expect(report.mock.calls[0]?.[1]).toEqual({
-        operation: "scheduled_workflow_run_now",
-        tenantId: "tenant-1",
-      });
-    } finally {
-      report.mockRestore();
-    }
-  });
-});
-
-describe("shellContextMenuFor: insights-run", () => {
-  test("offers open and copy-link, pointed at the run's canonical route", () => {
-    const target: ShellContextMenuTarget = {
-      type: "insights-run",
-      id: "run-1",
-    };
-    const navigate = mock((_to: string) => undefined);
-    const menu = shellContextMenuFor(target, actions({ navigate }));
-    expect(itemIds(menu.entries)).toEqual(["open", "copy-link"]);
-    findItem(menu.entries, "open").onSelect();
-    expect(navigate).toHaveBeenCalledWith("/insights/runs/run-1");
-  });
-});
-
-describe("shellContextMenuFor: artifact", () => {
-  test("a single right-clicked file offers exactly the Files bulk action bar's operation set", () => {
-    const target: ShellContextMenuTarget = {
-      type: "artifact",
-      id: "art_1",
-      ids: ["art_1"],
-    };
-    const menu = shellContextMenuFor(target, actions());
-    // Parity, not eyeballing: the context menu and the bulk action bar are
-    // driven off the exact same constant.
-    expect(itemIds(menu.entries)).toEqual([...LIBRARY_BULK_OPERATION_IDS]);
-    expect(findItem(menu.entries, "copy-link").label).toBe("Copy link");
-  });
-
-  test("right-clicking inside a multi-select still offers the same operation set, pluralized", () => {
-    const target: ShellContextMenuTarget = {
-      type: "artifact",
-      id: "art_2",
-      ids: ["art_1", "art_2", "art_3"],
-    };
-    const menu = shellContextMenuFor(target, actions());
-    expect(itemIds(menu.entries)).toEqual([...LIBRARY_BULK_OPERATION_IDS]);
-    expect(findItem(menu.entries, "copy-link").label).toBe("Copy 3 links");
-  });
-
-  test("copy-link writes every acted-on file's canonical link, newline-joined", async () => {
-    const target: ShellContextMenuTarget = {
-      type: "artifact",
-      id: "art_1",
-      ids: ["art_1", "art_2"],
-    };
-    const menu = shellContextMenuFor(target, actions());
-    findItem(menu.entries, "copy-link").onSelect();
-    await Promise.resolve();
-    await Promise.resolve();
-    expect(navigator.clipboard.writeText).toHaveBeenCalledWith(
-      `${window.location.origin}/artifacts/a/art_1\n${window.location.origin}/artifacts/a/art_2`,
-    );
-    expect(toastMock).toHaveBeenCalledWith("2 links copied");
-  });
-});
-
-describe("shellContextMenuFor: account", () => {
-  test("offers settings and sign-out, never a bare destructive gesture", () => {
-    const menu = shellContextMenuFor({ type: "account" }, actions());
-    expect(itemIds(menu.entries)).toEqual(["settings", "sign-out"]);
-  });
-
-  test("settings navigates to the settings route", () => {
-    const navigate = mock((_to: string) => undefined);
-    const menu = shellContextMenuFor({ type: "account" }, actions({ navigate }));
-    findItem(menu.entries, "settings").onSelect();
-    expect(navigate).toHaveBeenCalledWith("/settings");
-  });
-
-  test("sign-out only fires from its own explicit menu item", () => {
-    const signOut = mock(() => undefined);
-    const menu = shellContextMenuFor({ type: "account" }, actions({ signOut }));
-    expect(signOut).not.toHaveBeenCalled();
-    findItem(menu.entries, "sign-out").onSelect();
-    expect(signOut).toHaveBeenCalledTimes(1);
-  });
-});
-
-describe("shellContextMenuFor: shell", () => {
-  test("offers search, workbenches, and theme", () => {
-    const menu = shellContextMenuFor({ type: "shell" }, actions());
-    expect(itemIds(menu.entries)).toEqual(["search", "workbenches", "theme"]);
-  });
-
-  test("theme item calls cycleTheme", () => {
-    const cycleTheme = mock(() => undefined);
-    const menu = shellContextMenuFor({ type: "shell" }, actions({ cycleTheme }));
-    findItem(menu.entries, "theme").onSelect();
-    expect(cycleTheme).toHaveBeenCalledTimes(1);
-  });
-});
diff --git a/apps/web/src/shell/context-menu/items.tsx b/apps/web/src/shell/context-menu/items.tsx
index f45e9bbee..706cafea3 100644
--- a/apps/web/src/shell/context-menu/items.tsx
+++ b/apps/web/src/shell/context-menu/items.tsx
@@ -3,11 +3,7 @@
 // whose mock counterpart had no working backend (mark-read, mute, archive,
 // share) simply has no builder and so contributes no items.
 
-import {
-  patchWorkbenchSettings,
-  profileSubjectFromParticipant,
-  WORKBENCHES_MUTATED_EVENT,
-} from "@/chat";
+import { profileSubjectFromParticipant } from "@/chat";
 import type { ProfileSubject } from "@/chat";
 import { contextMenuItem, contextMenuSeparator } from "@/shell/context-menu/lib";
 import type { ContextMenu, ContextMenuEntry } from "@/shell/context-menu/lib";
@@ -20,8 +16,6 @@ import {
   MoonStars,
   PencilSimple,
   PlayCircle,
-  PushPin,
-  PushPinSlash,
   SignOut,
   SlidersHorizontal,
   UserCircle,
@@ -64,7 +58,6 @@ async function copyLink(path: string, label: string): Promise<void> {
 
 function workbenchMenu(
   target: Extract<ShellContextMenuTarget, { type: "workbench" }>,
-  actions: ShellContextMenuActions,
 ): ContextMenu {
   const entries: ContextMenuEntry[] = [
     contextMenuItem({
@@ -74,34 +67,6 @@ function workbenchMenu(
       onSelect: () => requestWorkbenchRename(target.id),
     }),
   ];
-  if (actions.tenantId !== null) {
-    const tenantId = actions.tenantId;
-    entries.push(
-      contextMenuItem({
-        id: "pin",
-        label: target.pinned ? "Unpin workbench" : "Pin workbench",
-        icon: target.pinned ? <PushPinSlash /> : <PushPin />,
-        onSelect: () => {
-          void patchWorkbenchSettings(tenantId, target.id, {
-            "chat/pinned": !target.pinned,
-          }).then(
-            () => {
-              // Settings persist without this, but the sidebar list caches
-              // its workbench fetch — without a mutation signal the pin
-              // has zero visible effect (no reorder, no glyph refresh).
-              window.dispatchEvent(
-                new CustomEvent(WORKBENCHES_MUTATED_EVENT, {
-                  detail: { tenantId },
-                }),
-              );
-              toast(target.pinned ? "Workbench unpinned" : "Workbench pinned");
-            },
-            () => toast("Couldn't update the workbench"),
-          );
-        },
-      }),
-    );
-  }
   entries.push(
     contextMenuSeparator,
     contextMenuItem({
@@ -287,7 +252,7 @@ export function shellContextMenuFor(
 ): ContextMenu {
   switch (target.type) {
     case "workbench":
-      return workbenchMenu(target, actions);
+      return workbenchMenu(target);
     case "profile":
       return profileMenu(target, actions);
     case "routine":
diff --git a/apps/web/src/shell/tenant-resolution.test.ts b/apps/web/src/shell/tenant-resolution.test.ts
deleted file mode 100644
index ed8bd4d4c..000000000
--- a/apps/web/src/shell/tenant-resolution.test.ts
+++ /dev/null
@@ -1,51 +0,0 @@
-import { describe, expect, test } from "bun:test";
-
-import { tenantResolutionFromBench } from "./tenant-resolution";
-
-describe("tenantResolutionFromBench", () => {
-  test("passes through loading memberships", () => {
-    expect(
-      tenantResolutionFromBench({
-        memberships: { kind: "loading" },
-        selectedTenantId: null,
-      }),
-    ).toEqual({ kind: "loading" });
-  });
-
-  test("passes through error memberships", () => {
-    expect(
-      tenantResolutionFromBench({
-        memberships: {
-          kind: "error",
-          message: "offline",
-          retry: () => undefined,
-        },
-        selectedTenantId: "tnt_1",
-      }),
-    ).toMatchObject({ kind: "error", message: "offline" });
-  });
-
-  test("ready with no selection is empty", () => {
-    expect(
-      tenantResolutionFromBench({
-        memberships: {
-          kind: "ready",
-          data: { data: [], nextCursor: null },
-        },
-        selectedTenantId: null,
-      }),
-    ).toEqual({ kind: "empty" });
-  });
-
-  test("ready with a selection yields that tenant id", () => {
-    expect(
-      tenantResolutionFromBench({
-        memberships: {
-          kind: "ready",
-          data: { data: [], nextCursor: null },
-        },
-        selectedTenantId: "tnt_acme",
-      }),
-    ).toEqual({ kind: "ready", tenantId: "tnt_acme" });
-  });
-});
diff --git a/apps/web/src/shell/tenant-resolution.ts b/apps/web/src/shell/tenant-resolution.ts
deleted file mode 100644
index 820852a51..000000000
--- a/apps/web/src/shell/tenant-resolution.ts
+++ /dev/null
@@ -1,19 +0,0 @@
-// Single place that turns the bench context into chat-ui's TenantResolution.
-// Chat mounts (main-pane fallback and canvas column) share this so they never
-// diverge on empty/loading/ready handling.
-
-import type { TenantResolution } from "@/chat";
-
-import type { useBench } from "../bench-context";
-
-type BenchSlice = Pick<ReturnType<typeof useBench>, "memberships" | "selectedTenantId">;
-
-export function tenantResolutionFromBench(bench: BenchSlice): TenantResolution {
-  if (bench.memberships.kind !== "ready") {
-    return bench.memberships;
-  }
-  if (bench.selectedTenantId === null) {
-    return { kind: "empty" };
-  }
-  return { kind: "ready", tenantId: bench.selectedTenantId };
-}
diff --git a/apps/web/src/workbench-create.ts b/apps/web/src/workbench-create.ts
new file mode 100644
index 000000000..cd4858433
--- /dev/null
+++ b/apps/web/src/workbench-create.ts
@@ -0,0 +1,98 @@
+// Creating a workbench is creating a child tenant and deploying an agent
+// into it: the stock member invite only takes a real user's email, and a
+// child tenant's deploy route rejects the parent's inherited asset, so an
+// agent joins a room by being deployed there — with the child's own
+// resolved offering, which does inherit.
+
+import { listRoomParticipants, sendToRoom } from "@/chat/threads-api";
+import { deployMyraSource } from "./myra-deploy";
+import { createFetchStockHub } from "./needs-converge";
+import { resolveExistingOffering } from "./onboarding/provider-connect-step";
+import { publishToolPackageRegistry } from "./tools/registry-publish";
+
+export class WorkbenchCreateError extends Error {
+  constructor(
+    message: string,
+    readonly stage: "create" | "deploy" | "opening-message",
+  ) {
+    super(message);
+    this.name = "WorkbenchCreateError";
+  }
+}
+
+/** Slugs are tenant-unique and immutable, so a name alone cannot mint one:
+ * the timestamp suffix is what keeps two rooms of the same name apart. */
+function workbenchSlug(name: string): string {
+  const base = name
+    .toLocaleLowerCase()
+    .replace(/[^a-z0-9]+/g, "-")
+    .replace(/^-|-$/g, "")
+    .slice(0, 32);
+  return `${base === "" ? "workbench" : base}-${Date.now().toString(36)}`;
+}
+
+function failure(cause: unknown, stage: WorkbenchCreateError["stage"]): WorkbenchCreateError {
+  return new WorkbenchCreateError(cause instanceof Error ? cause.message : String(cause), stage);
+}
+
+export type CreateWorkbenchInput = {
+  readonly benchTenantId: string;
+  readonly name: string;
+  readonly openingMessage?: string;
+};
+
+/** Returns the new room's tenant id — its deep link is `/w/<id>`. */
+export async function createWorkbench(input: CreateWorkbenchInput): Promise<string> {
+  const hub = createFetchStockHub();
+
+  let tenantId: string;
+  let domain: string;
+  try {
+    const created = await hub.createTenant({
+      name: input.name,
+      slug: workbenchSlug(input.name),
+      parentId: input.benchTenantId,
+    });
+    tenantId = created.id;
+    domain = created.domain;
+  } catch (cause) {
+    throw failure(cause, "create");
+  }
+
+  try {
+    // Myra's tool pins resolve from the room's own registry, so the
+    // packages have to be there before her definition deploys.
+    await publishToolPackageRegistry(tenantId);
+    const offering = await resolveExistingOffering(tenantId);
+    if (offering === null) {
+      throw new Error("Connect a model provider in Settings before starting a workbench.");
+    }
+    const deployInput = await deployMyraSource({
+      tenantId,
+      tenantDomain: domain,
+      sourceOfferingIds: offering.sourceOfferingIds,
+      defaultSourceOfferingId: offering.defaultSourceOfferingId,
+      declaredSources: offering.declaredSources,
+    });
+    await hub.deployWorkflow(tenantId, deployInput);
+  } catch (cause) {
+    throw failure(cause, "deploy");
+  }
+
+  if (input.openingMessage !== undefined && input.openingMessage !== "") {
+    try {
+      const participants = await listRoomParticipants(tenantId);
+      const agents = participants.filter((participant) => participant.kind === "agent");
+      // A deployment's run address exists only once the deploy settles; a
+      // room whose agent has not surfaced yet keeps the opening message
+      // for the person to send from the room itself.
+      if (agents.length > 0) {
+        await sendToRoom({ roomTenantId: tenantId, agents, content: input.openingMessage });
+      }
+    } catch (cause) {
+      throw failure(cause, "opening-message");
+    }
+  }
+
+  return tenantId;
+}
diff --git a/apps/web/src/workbench-path.ts b/apps/web/src/workbench-path.ts
index f26115ef4..bfa815c88 100644
--- a/apps/web/src/workbench-path.ts
+++ b/apps/web/src/workbench-path.ts
@@ -8,9 +8,16 @@
 // `/settings/:section` and `settingsEntityIdFromPath` for the app-level
 // Settings page.
 
-import { isWorkbenchSettingsSectionId, type WorkbenchSettingsSectionId } from "@/chat";
 import { decodedOrNull } from "@corbits/url-path";
 
+/** The settings sub-paths a workbench deep link still resolves. */
+export const WORKBENCH_SETTINGS_SECTION_IDS = ["general", "members", "agents", "danger"] as const;
+export type WorkbenchSettingsSectionId = (typeof WORKBENCH_SETTINGS_SECTION_IDS)[number];
+
+function isWorkbenchSettingsSectionId(value: string): value is WorkbenchSettingsSectionId {
+  return (WORKBENCH_SETTINGS_SECTION_IDS as readonly string[]).includes(value);
+}
+
 export const WORKBENCH_PATH_PREFIX = "/w";
 const LEGACY_CHAT_PATH_PREFIX = "/chat";
 const SETTINGS_SUFFIX = "/settings";
diff --git a/apps/web/src/workbench-timeline-merge.test.ts b/apps/web/src/workbench-timeline-merge.test.ts
deleted file mode 100644
index 701d80716..000000000
--- a/apps/web/src/workbench-timeline-merge.test.ts
+++ /dev/null
@@ -1,256 +0,0 @@
-import { describe, expect, test } from "bun:test";
-import type { WorkbenchThread, MessageItem } from "@/chat";
-
-import type { PendingApproval } from "./pending-approvals";
-import {
-  computeTimelineDayKpis,
-  filterTimelineEvents,
-  groupTimelineByDay,
-  mergeTimelineEvents,
-  toApprovalEvents,
-  toMessageEvents,
-  toThreadForkEvents,
-  type TimelineEvent,
-} from "./workbench-timeline-merge";
-
-function message(overrides: Partial<MessageItem> = {}): MessageItem {
-  return {
-    id: "msg-1",
-    createdAt: "2026-08-17T10:00:00.000Z",
-    parts: [{ kind: "text", text: "hello there" }],
-    sender: { name: "Sawyer", address: "sawyer@bench-1" },
-    ...overrides,
-  } as MessageItem;
-}
-
-function thread(overrides: Partial<WorkbenchThread> = {}): WorkbenchThread {
-  return {
-    id: "thread-1",
-    kind: "reply",
-    parentMessageId: "msg-1",
-    parentThreadId: null,
-    runRef: null,
-    title: "A fork",
-    createdAt: "2026-08-17T10:05:00.000Z",
-    ...overrides,
-  } as WorkbenchThread;
-}
-
-function approval(overrides: Partial<PendingApproval> = {}): PendingApproval {
-  return {
-    id: "approval-1",
-    agentName: "Researcher",
-    benchName: "Acme",
-    headline: "Send the email",
-    arguments: {},
-    status: "pending",
-    createdAt: "2026-08-17T12:00:00.000Z",
-    ...overrides,
-  } as PendingApproval;
-}
-
-describe("toMessageEvents", () => {
-  test("joins text parts and truncates the excerpt at 120 chars", () => {
-    const long = "a".repeat(200);
-    const [event] = toMessageEvents([message({ parts: [{ kind: "text", text: long }] })]);
-    expect(event?.excerpt.length).toBe(121);
-    expect(event?.excerpt.endsWith("…")).toBe(true);
-  });
-
-  test("falls back to the sender's local part, never the raw address", () => {
-    const [event] = toMessageEvents([
-      message({ sender: { name: null, address: "echo@workbench-1" } }),
-    ]);
-    expect(event?.senderName).toBe("echo");
-  });
-
-  test("marks an agent sender via its @-shaped address", () => {
-    const [event] = toMessageEvents([
-      message({ sender: { name: null, address: "researcher@workbench-1" } }),
-    ]);
-    expect(event?.isAgent).toBe(true);
-  });
-
-  test("marks a human sender (no @) as not an agent", () => {
-    const [event] = toMessageEvents([
-      message({ sender: { name: "Sawyer", address: "principal-123" } }),
-    ]);
-    expect(event?.isAgent).toBe(false);
-  });
-
-  test("empty parts render an honest placeholder, never a blank excerpt", () => {
-    const [event] = toMessageEvents([message({ parts: [] })]);
-    expect(event?.excerpt).toBe("(no text)");
-  });
-});
-
-describe("toThreadForkEvents", () => {
-  test("drops the root thread", () => {
-    const events = toThreadForkEvents([
-      thread({ id: "root-1", kind: "root" }),
-      thread({ id: "fork-1", kind: "reply" }),
-    ]);
-    expect(events.map((e) => e.id)).toEqual(["fork-1"]);
-  });
-
-  test("titles a fork with no title 'Thread'", () => {
-    const [event] = toThreadForkEvents([thread({ title: null })]);
-    expect(event?.title).toBe("Thread");
-  });
-});
-
-describe("toApprovalEvents", () => {
-  test("carries every pending approval through unfiltered", () => {
-    const events = toApprovalEvents([approval()]);
-    expect(events).toEqual([
-      {
-        kind: "approval",
-        id: "approval-1",
-        at: "2026-08-17T12:00:00.000Z",
-        agentName: "Researcher",
-        headline: "Send the email",
-      },
-    ]);
-  });
-});
-
-describe("mergeTimelineEvents", () => {
-  test("sorts every kind onto one oldest-first spine", () => {
-    const merged = mergeTimelineEvents({
-      messages: toMessageEvents([message({ id: "m1", createdAt: "2026-08-17T10:00:00.000Z" })]),
-      threadForks: toThreadForkEvents([
-        thread({ id: "f1", createdAt: "2026-08-17T09:30:00.000Z" }),
-      ]),
-      approvals: toApprovalEvents([approval({ id: "a1", createdAt: "2026-08-17T12:00:00.000Z" })]),
-    });
-    expect(merged.map((e) => e.id)).toEqual(["f1", "m1", "a1"]);
-  });
-
-  test("drops an event with an unparseable timestamp instead of sorting it arbitrarily", () => {
-    const merged = mergeTimelineEvents({
-      messages: toMessageEvents([message({ id: "m1", createdAt: "not-a-date" })]),
-      threadForks: [],
-      approvals: [],
-    });
-    expect(merged).toEqual([]);
-  });
-});
-
-describe("groupTimelineByDay", () => {
-  test("buckets an already-sorted spine by UTC calendar day, oldest day first", () => {
-    const events: TimelineEvent[] = [
-      {
-        kind: "message",
-        id: "m1",
-        at: "2026-08-16T23:00:00.000Z",
-        senderName: "A",
-        excerpt: "x",
-        isAgent: false,
-      },
-      {
-        kind: "message",
-        id: "m2",
-        at: "2026-08-17T01:00:00.000Z",
-        senderName: "A",
-        excerpt: "y",
-        isAgent: false,
-      },
-      {
-        kind: "message",
-        id: "m3",
-        at: "2026-08-17T02:00:00.000Z",
-        senderName: "A",
-        excerpt: "z",
-        isAgent: false,
-      },
-    ];
-    const groups = groupTimelineByDay(events);
-    expect(groups.map((g) => g.day)).toEqual(["2026-08-16", "2026-08-17"]);
-    expect(groups[0]?.events.map((e) => e.id)).toEqual(["m1"]);
-    expect(groups[1]?.events.map((e) => e.id)).toEqual(["m2", "m3"]);
-  });
-});
-
-describe("computeTimelineDayKpis", () => {
-  test("counts messages, agent turns, and approvals per day", () => {
-    const events: TimelineEvent[] = [
-      {
-        kind: "message",
-        id: "m1",
-        at: "2026-08-17T09:00:00.000Z",
-        senderName: "A",
-        excerpt: "x",
-        isAgent: false,
-      },
-      {
-        kind: "message",
-        id: "m2",
-        at: "2026-08-17T09:05:00.000Z",
-        senderName: "researcher",
-        excerpt: "y",
-        isAgent: true,
-      },
-      {
-        kind: "approval",
-        id: "a1",
-        at: "2026-08-17T09:15:00.000Z",
-        agentName: "Researcher",
-        headline: "Do it",
-      },
-      {
-        kind: "thread-fork",
-        id: "f1",
-        at: "2026-08-17T09:25:00.000Z",
-        threadKind: "reply",
-        title: "Fork",
-        parentMessageId: null,
-      },
-    ];
-    const [kpi] = computeTimelineDayKpis(events);
-    expect(kpi).toMatchObject({
-      messages: 2,
-      agentTurns: 1,
-      approvals: 1,
-    });
-  });
-});
-
-describe("filterTimelineEvents", () => {
-  const events: TimelineEvent[] = [
-    {
-      kind: "message",
-      id: "m1",
-      at: "2026-08-17T09:00:00.000Z",
-      senderName: "A",
-      excerpt: "x",
-      isAgent: false,
-    },
-    {
-      kind: "thread-fork",
-      id: "f1",
-      at: "2026-08-17T09:01:00.000Z",
-      threadKind: "reply",
-      title: "Fork",
-      parentMessageId: null,
-    },
-    {
-      kind: "approval",
-      id: "a1",
-      at: "2026-08-17T09:04:00.000Z",
-      agentName: "Researcher",
-      headline: "Do it",
-    },
-  ];
-
-  test("all keeps everything", () => {
-    expect(filterTimelineEvents(events, "all")).toHaveLength(3);
-  });
-
-  test("messages keeps messages and thread forks", () => {
-    expect(filterTimelineEvents(events, "messages").map((e) => e.id)).toEqual(["m1", "f1"]);
-  });
-
-  test("approvals keeps only approvals", () => {
-    expect(filterTimelineEvents(events, "approvals").map((e) => e.id)).toEqual(["a1"]);
-  });
-});
diff --git a/apps/web/src/workbench-timeline-merge.ts b/apps/web/src/workbench-timeline-merge.ts
deleted file mode 100644
index a7872b4a2..000000000
--- a/apps/web/src/workbench-timeline-merge.ts
+++ /dev/null
@@ -1,222 +0,0 @@
-// Pure merge over the event kinds a per-workbench Timeline draws from
-// (chat messages, thread forks, approvals) — one wall-clock spine, oldest
-// first, with day dividers and KPI rollups derived from the same merged
-// array. No new backend: every input here is already fetched by an
-// existing page (chat-ui, api.ts).
-
-import { isAgentAddress } from "@/chat/wire/mentions";
-import { localPartOf } from "@/chat/wire/agent-address";
-import type { WorkbenchThread, MessageItem } from "@/chat";
-
-import type { PendingApproval } from "./pending-approvals";
-
-export type TimelineMessageEvent = {
-  readonly kind: "message";
-  readonly id: string;
-  readonly at: string;
-  readonly senderName: string;
-  readonly excerpt: string;
-  readonly isAgent: boolean;
-};
-
-export type TimelineThreadForkEvent = {
-  readonly kind: "thread-fork";
-  readonly id: string;
-  readonly at: string;
-  readonly threadKind: "reply" | "delivery";
-  readonly title: string;
-  readonly parentMessageId: string | null;
-};
-
-export type TimelineApprovalEvent = {
-  readonly kind: "approval";
-  readonly id: string;
-  readonly at: string;
-  readonly agentName: string;
-  readonly headline: string;
-};
-
-export type TimelineEvent = TimelineMessageEvent | TimelineThreadForkEvent | TimelineApprovalEvent;
-
-const EXCERPT_LIMIT = 120;
-
-function messageExcerpt(item: MessageItem): string {
-  const text = item.parts
-    .filter((part) => part.kind === "text")
-    .map((part) => part.text)
-    .join(" ")
-    .trim();
-  if (text === "") return "(no text)";
-  return text.length > EXCERPT_LIMIT ? `${text.slice(0, EXCERPT_LIMIT)}…` : text;
-}
-
-/** Never the raw address (a per-workbench local id shape) — falls back to
- * its friendly local part when the sender has no display name. */
-function senderDisplayName(sender: MessageItem["sender"]): string {
-  return sender.name ?? localPartOf(sender.address);
-}
-
-export function toMessageEvents(items: readonly MessageItem[]): readonly TimelineMessageEvent[] {
-  return items.map((item) => ({
-    kind: "message",
-    id: item.id,
-    at: item.createdAt,
-    senderName: senderDisplayName(item.sender),
-    excerpt: messageExcerpt(item),
-    isAgent: isAgentAddress(item.sender.address),
-  }));
-}
-
-/** Every fork off the workbench's root thread — the root itself (the plain
- * workbench timeline) never renders as its own spine entry. */
-export function toThreadForkEvents(
-  threads: readonly WorkbenchThread[],
-): readonly TimelineThreadForkEvent[] {
-  return threads
-    .filter((thread) => thread.kind !== "root")
-    .map((thread) => ({
-      kind: "thread-fork",
-      id: thread.id,
-      at: thread.createdAt,
-      threadKind: thread.kind === "reply" ? "reply" : "delivery",
-      title: thread.title ?? "Thread",
-      parentMessageId: thread.parentMessageId,
-    }));
-}
-
-/**
- * An approval carries no workbench id (a known v1 gap — see
- * workbench-timeline.tsx), so every pending approval for the owning bench
- * shows up here, not just this workbench's own.
- */
-export function toApprovalEvents(
-  items: readonly PendingApproval[],
-): readonly TimelineApprovalEvent[] {
-  return items.map((item) => ({
-    kind: "approval",
-    id: item.id,
-    at: item.createdAt,
-    agentName: item.agentName,
-    headline: item.headline,
-  }));
-}
-
-export type TimelineEventGroups = {
-  readonly messages: readonly TimelineMessageEvent[];
-  readonly threadForks: readonly TimelineThreadForkEvent[];
-  readonly approvals: readonly TimelineApprovalEvent[];
-};
-
-/** One wall-clock spine, oldest first. An event with an unparseable
- * timestamp is dropped rather than sorted arbitrarily. */
-export function mergeTimelineEvents(groups: TimelineEventGroups): readonly TimelineEvent[] {
-  const all: TimelineEvent[] = [...groups.messages, ...groups.threadForks, ...groups.approvals];
-  return all
-    .filter((event) => !Number.isNaN(Date.parse(event.at)))
-    .sort((a, b) => {
-      const delta = Date.parse(a.at) - Date.parse(b.at);
-      return delta !== 0 ? delta : a.id.localeCompare(b.id);
-    });
-}
-
-export type TimelineDayGroup = {
-  readonly day: string;
-  readonly label: string;
-  readonly events: readonly TimelineEvent[];
-};
-
-function utcDayKey(iso: string): string {
-  const d = new Date(iso);
-  const y = d.getUTCFullYear();
-  const m = String(d.getUTCMonth() + 1).padStart(2, "0");
-  const day = String(d.getUTCDate()).padStart(2, "0");
-  return `${y}-${m}-${day}`;
-}
-
-function dayLabel(key: string): string {
-  const [y, m, d] = key.split("-").map(Number) as [number, number, number];
-  return new Date(Date.UTC(y, m - 1, d)).toLocaleDateString(undefined, {
-    month: "long",
-    day: "numeric",
-    year: "numeric",
-    timeZone: "UTC",
-  });
-}
-
-/** Buckets an already-sorted (oldest first) spine by UTC calendar day,
- * preserving that order across day boundaries. */
-export function groupTimelineByDay(events: readonly TimelineEvent[]): readonly TimelineDayGroup[] {
-  const order: string[] = [];
-  const buckets = new Map<string, TimelineEvent[]>();
-  for (const event of events) {
-    const key = utcDayKey(event.at);
-    let bucket = buckets.get(key);
-    if (bucket === undefined) {
-      bucket = [];
-      buckets.set(key, bucket);
-      order.push(key);
-    }
-    bucket.push(event);
-  }
-  return order.map((key) => ({
-    day: key,
-    label: dayLabel(key),
-    events: buckets.get(key) as TimelineEvent[],
-  }));
-}
-
-export type TimelineDayKpi = {
-  readonly day: string;
-  readonly label: string;
-  readonly messages: number;
-  readonly agentTurns: number;
-  readonly approvals: number;
-};
-
-/** The right rail's per-day KPI list — counts only, computed straight off
- * the merged spine so it can never disagree with what's rendered. */
-export function computeTimelineDayKpis(
-  events: readonly TimelineEvent[],
-): readonly TimelineDayKpi[] {
-  return groupTimelineByDay(events).map((group) => {
-    let messages = 0;
-    let agentTurns = 0;
-    let approvals = 0;
-    for (const event of group.events) {
-      switch (event.kind) {
-        case "message":
-          messages += 1;
-          if (event.isAgent) agentTurns += 1;
-          break;
-        case "approval":
-          approvals += 1;
-          break;
-        case "thread-fork":
-          break;
-      }
-    }
-    return {
-      day: group.day,
-      label: group.label,
-      messages,
-      agentTurns,
-      approvals,
-    };
-  });
-}
-
-export type TimelineFilter = "all" | "messages" | "approvals";
-
-export function filterTimelineEvents(
-  events: readonly TimelineEvent[],
-  filter: TimelineFilter,
-): readonly TimelineEvent[] {
-  switch (filter) {
-    case "all":
-      return events;
-    case "messages":
-      return events.filter((event) => event.kind === "message" || event.kind === "thread-fork");
-    case "approvals":
-      return events.filter((event) => event.kind === "approval");
-  }
-}