diff --git a/packages/chat-ui/src/api.ts b/packages/chat-ui/src/api.ts
index 511a578a7..9eb52adbd 100644
--- a/packages/chat-ui/src/api.ts
+++ b/packages/chat-ui/src/api.ts
@@ -54,6 +54,7 @@ const WorkbenchWire = type({
   pinned: "boolean",
   "definitionId?": "string | null",
   participants: "unknown[]",
+  "owner?": type({ address: "string", handle: "string" }).or("null"),
   "legacy?": "boolean",
   // Row signals `GET /workbenches` annotates when it can resolve a
   // workbench's mailbox (see `packages/chat/src/routes.ts`): absent,
diff --git a/packages/chat-ui/src/chat-members.tsx b/packages/chat-ui/src/chat-members.tsx
new file mode 100644
index 000000000..37ad89b76
--- /dev/null
+++ b/packages/chat-ui/src/chat-members.tsx
@@ -0,0 +1,194 @@
+import { useId } from "react";
+import {
+  Avatar,
+  Button,
+  Menu,
+  MenuContent,
+  MenuItem,
+  MenuTrigger,
+  useDismissablePopover,
+} from "@corbits/react-ui";
+import { CaretDown, DotsThree, Plus } from "@corbits/icons";
+
+import type { WorkbenchAgent } from "./api";
+import { CorbitAvatar } from "./avatar";
+import type { TeamAvatarEntry } from "./chat-workspace";
+import { localPartOf } from "./timeline";
+
+export function ChatMembers({
+  members,
+  agents,
+  currentUserPrincipalId,
+  onInvite,
+  onEditAgent,
+}: {
+  readonly members: readonly TeamAvatarEntry[];
+  readonly agents: readonly WorkbenchAgent[];
+  readonly currentUserPrincipalId: string | undefined;
+  readonly onInvite: (() => void) | undefined;
+  readonly onEditAgent: ((definitionId: string) => void) | undefined;
+}) {
+  const { open, setOpen, rootRef, triggerRef, close } = useDismissablePopover<
+    HTMLDivElement,
+    HTMLButtonElement
+  >();
+  const panelId = useId();
+  const agentCount = members.filter((member) => member.tone === "agent").length;
+  const peopleCount = members.length - agentCount;
+  const representatives = [
+    members.find((member) => member.tone === "agent"),
+    members.find((member) => member.tone === "neutral"),
+  ].filter((member) => member !== undefined);
+
+  const preview =
+    representatives.length === 2 ? representatives : members.slice(0, 2);
+
+  return (
+    <div ref={rootRef} className="relative">
+      <Button
+        ref={triggerRef}
+        variant="ghost"
+        className="gap-3 rounded-lg bg-muted px-3"
+        aria-expanded={open}
+        aria-controls={panelId}
+        aria-label={`${members.length} ${members.length === 1 ? "member" : "members"}`}
+        onClick={() => setOpen(!open)}
+      >
+        <span
+          className="chat-member-stack flex items-center"
+          aria-hidden="true"
+        >
+          {preview.map((member, index) => (
+            <span
+              key={member.key}
+              title={member.label}
+              data-agent={member.tone === "agent" ? "true" : undefined}
+              className={`member-avatar relative flex size-6 shrink-0 items-center justify-center ${index === 0 ? "z-10" : "-ml-1.5"}`}
+            >
+              {member.tone === "agent" ? (
+                <CorbitAvatar
+                  size="sm"
+                  ariaLabel={member.label}
+                  className="[&_svg]:!size-full"
+                />
+              ) : (
+                <Avatar
+                  size="sm"
+                  initials={member.initials}
+                  label={member.label}
+                  className={`rounded-full ${member.avatarClassName ?? ""}`}
+                />
+              )}
+            </span>
+          ))}
+        </span>
+        <span className="border-l border-border pl-3 text-sm font-normal">
+          {members.length} {members.length === 1 ? "member" : "members"}
+        </span>
+        <CaretDown
+          aria-hidden="true"
+          className="size-4 text-muted-foreground"
+        />
+      </Button>
+      {open ? (
+        <section
+          id={panelId}
+          aria-label="Members"
+          className="fixed inset-x-4 z-50 mt-2 sm:absolute sm:inset-x-auto sm:right-0 sm:top-full sm:w-80 rounded-xl border border-border bg-popover p-4 text-popover-foreground shadow-lg"
+        >
+          <h2 className="text-base font-semibold">Members</h2>
+          <p className="text-sm text-muted-foreground">
+            {peopleCount} {peopleCount === 1 ? "person" : "people"} ·{" "}
+            {agentCount} {agentCount === 1 ? "agent" : "agents"}
+          </p>
+          <ul className="my-3 max-h-72 overflow-y-auto">
+            {members.map((member) => {
+              const self =
+                member.tone === "neutral" &&
+                localPartOf(member.key) === currentUserPrincipalId;
+              const agent = agents.find(
+                (candidate) => candidate.address === member.key,
+              );
+              const editable = agent !== undefined && onEditAgent !== undefined;
+              return (
+                <li
+                  key={member.key}
+                  className="chat-member-row flex items-start gap-3 rounded-md px-2 py-2 transition-colors hover:bg-muted focus-within:bg-muted"
+                >
+                  {member.tone === "agent" ? (
+                    <CorbitAvatar size="lg" ariaLabel={member.label} />
+                  ) : (
+                    <Avatar
+                      size="lg"
+                      initials={member.initials}
+                      label={member.label}
+                      className={`rounded-full ${member.avatarClassName ?? ""}`}
+                    />
+                  )}
+                  <div className="min-w-0 flex-1">
+                    <p className="truncate text-sm font-semibold">
+                      {member.label}
+                    </p>
+                    <p className="text-sm text-muted-foreground">
+                      {self
+                        ? "You"
+                        : member.tone === "agent"
+                          ? "Agent"
+                          : "Member"}
+                    </p>
+                  </div>
+                  {editable ? (
+                    <Menu>
+                      <MenuTrigger asChild>
+                        <button
+                          type="button"
+                          aria-label={`Actions for ${member.label}`}
+                          className="flex min-h-10 w-10 shrink-0 cursor-pointer items-center justify-center rounded-md border-0 bg-transparent text-muted-foreground transition-colors hover:bg-muted hover:text-foreground focus-visible:outline-2 focus-visible:outline-ring"
+                        >
+                          <DotsThree aria-hidden="true" className="size-5" />
+                        </button>
+                      </MenuTrigger>
+                      <MenuContent
+                        align="start"
+                        onEscapeKeyDown={(event) => event.stopPropagation()}
+                        onCloseAutoFocus={(event) => {
+                          if (open) return;
+                          event.preventDefault();
+                          triggerRef.current?.focus();
+                        }}
+                        onPointerDown={(event) => event.stopPropagation()}
+                      >
+                        <MenuItem
+                          onSelect={() => {
+                            close();
+                            onEditAgent(agent.definitionId);
+                          }}
+                        >
+                          Edit agent
+                        </MenuItem>
+                      </MenuContent>
+                    </Menu>
+                  ) : null}
+                </li>
+              );
+            })}
+          </ul>
+          {onInvite !== undefined ? (
+            <div className="border-t border-border pt-3">
+              <Button
+                className="w-full"
+                onClick={() => {
+                  close();
+                  onInvite();
+                }}
+              >
+                <Plus aria-hidden="true" />
+                Add member
+              </Button>
+            </div>
+          ) : null}
+        </section>
+      ) : null}
+    </div>
+  );
+}
diff --git a/packages/chat-ui/src/chat-workspace.test.ts b/packages/chat-ui/src/chat-workspace.test.ts
index 247112953..c1f89f6c8 100644
--- a/packages/chat-ui/src/chat-workspace.test.ts
+++ b/packages/chat-ui/src/chat-workspace.test.ts
@@ -66,6 +66,28 @@ describe("buildMemberAvatarStack", () => {
     expect(stack.map((entry) => entry.initials)).toEqual(["A"]);
   });
 
+  test("includes the native owner missing from the mention roster, never the viewer", () => {
+    const stack = buildMemberAvatarStack(
+      [{ address: "myra@agents.example", handle: "myra" }],
+      undefined,
+      { principalId: "prn_bob", name: "Bob" },
+      { address: "prn_alice", handle: "Alice" },
+    );
+    expect(stack.map((entry) => entry.label)).toEqual(["Myra", "Alice"]);
+  });
+
+  test("does not duplicate an owner already in the roster and protects that row", () => {
+    const owner = { address: "prn_alice", handle: "Alice" };
+    const stack = buildMemberAvatarStack(
+      [owner],
+      undefined,
+      { principalId: "prn_alice", name: "Alice Smith" },
+      owner,
+    );
+    expect(stack).toHaveLength(1);
+    expect(stack[0]?.label).toBe("Alice Smith");
+  });
+
   test("prefers resolved agent display names over handle slugs (CL-6424)", () => {
     const participants: readonly ParticipantRecord[] = [
       { address: "run_myra@dana.localhost", handle: "myra" },
diff --git a/packages/chat-ui/src/chat-workspace.tsx b/packages/chat-ui/src/chat-workspace.tsx
index fbe4ec088..32dd9881a 100644
--- a/packages/chat-ui/src/chat-workspace.tsx
+++ b/packages/chat-ui/src/chat-workspace.tsx
@@ -19,7 +19,6 @@ import {
   CaretDown,
   ChatCircle,
   SlidersHorizontal,
-  UserPlus,
   WarningCircle,
 } from "@corbits/icons";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
@@ -116,8 +115,8 @@ import {
   applyStreamReaction,
   useWorkbenchFeed,
 } from "./use-workbench-feed";
-import { CorbitAvatar, avatarClassForPrincipal } from "./avatar";
-import { useWorkbenchPresenceRoster } from "./workbench-presence";
+import { avatarClassForPrincipal } from "./avatar";
+import { ChatMembers } from "./chat-members";
 import { type } from "arktype";
 import {
   ChatMessageEventData,
@@ -153,22 +152,8 @@ export type TenantResolution =
   | { readonly kind: "empty" }
   | { readonly kind: "ready"; readonly tenantId: string };
 
-/**
- * One live presence entry for the workbench's who's-here stack (CL-6328) —
- * 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. */
+ * human, normalized for the member control and popover. */
 export interface TeamAvatarEntry {
   readonly key: string;
   readonly initials: string;
@@ -177,11 +162,6 @@ export interface TeamAvatarEntry {
   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 = {
@@ -206,8 +186,7 @@ const WORKBENCHES_LIST_CHROME: ChatHeaderChrome = {
  * 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 (CL-6779) — 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.
+ * signed-in human as a participant before any live update arrives.
  *
  * Each person gets a stable generated color keyed by address. Human labels
  * prefer `currentUser.name` when the roster entry
@@ -217,7 +196,13 @@ export function buildMemberAvatarStack(
   participants: readonly ParticipantRecord[],
   displayNames?: AgentDisplayNames,
   currentUser?: CurrentUser,
+  owner?: ParticipantRecord | null,
 ): readonly TeamAvatarEntry[] {
+  const roster =
+    owner != null &&
+    !participants.some((participant) => participant.address === owner.address)
+      ? [...participants, owner]
+      : participants;
   const agents = participants
     .filter((participant) => isAgentAddress(participant.address))
     .map((participant) => {
@@ -232,12 +217,12 @@ export function buildMemberAvatarStack(
       };
     });
 
-  const humans = participants
+  const humans = roster
     .filter((participant) => !isAgentAddress(participant.address))
     .map((participant) => {
       const label = typingLabel(
         localPartOf(participant.address),
-        participants,
+        roster,
         currentUser,
       );
       return {
@@ -896,8 +881,6 @@ function ChatWorkspaceInner({
   } = 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
@@ -953,7 +936,6 @@ function ChatWorkspaceInner({
       handleTypingEvent(eventType, data);
       handleStreamingReplyEvent(eventType, data);
       handleTurnActivityEvent(eventType, data);
-      handlePresenceEvent(eventType, data);
       if (activeWorkbenchId === null) return;
       switch (eventType) {
         case "chat.message": {
@@ -1323,43 +1305,13 @@ function ChatWorkspaceInner({
     !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 (CL-6328), 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.
+  // Membership includes offline participants.
   const memberStack = buildMemberAvatarStack(
     activeWorkbench?.participants ?? [],
     agentDisplayNames,
     currentUser,
+    activeWorkbench?.owner,
   );
-  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" &&
@@ -1417,78 +1369,22 @@ function ChatWorkspaceInner({
           </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}
-      {offerInviteControl ? (
-        <Button
-          variant="outline"
-          size="sm"
-          onClick={() => setInviteDialogOpen(true)}
-        >
-          <UserPlus />
-          {CHAT_STRINGS.inviteAgentAction}
-        </Button>
+      {activeWorkbenchId !== null &&
+      (memberStack.length > 0 || offerInviteControl) ? (
+        <ChatMembers
+          key={activeWorkbenchId}
+          members={memberStack}
+          agents={workbenchAgentsQuery.data ?? []}
+          currentUserPrincipalId={currentUser?.principalId}
+          onInvite={
+            offerInviteControl ? () => setInviteDialogOpen(true) : undefined
+          }
+          onEditAgent={
+            onSettingsOpenChange !== undefined
+              ? (definitionId) => openWorkbenchSettings("agents", definitionId)
+              : undefined
+          }
+        />
       ) : null}
       <div className="chat-workbench-settings-slot">
         <Button
diff --git a/packages/chat-ui/src/index.ts b/packages/chat-ui/src/index.ts
index 0215c5cec..8d908b234 100644
--- a/packages/chat-ui/src/index.ts
+++ b/packages/chat-ui/src/index.ts
@@ -1,7 +1,6 @@
 export { ChatWorkspace } from "./chat-workspace";
 export type {
   TenantResolution,
-  PresenceMember,
   ChatHeaderChrome,
   ChatHeaderCrumb,
 } from "./chat-workspace";
diff --git a/packages/chat-ui/src/strings.ts b/packages/chat-ui/src/strings.ts
index 9fc74fcdd..343991d8a 100644
--- a/packages/chat-ui/src/strings.ts
+++ b/packages/chat-ui/src/strings.ts
@@ -113,9 +113,6 @@ export const CHAT_STRINGS = {
 
   inviteAgentAction: "Invite agent",
   workbenchMembersLabel: "Members",
-  workbenchPresenceLabel: "Live",
-  teamStackOverflow: (count: number) =>
-    `${count} more ${count === 1 ? "member" : "members"}`,
   threadsMenuCount: (count: number) =>
     `${count} ${count === 1 ? "thread" : "threads"}`,
   inviteAgentDialogTitle: "Invite an agent",
diff --git a/packages/chat-ui/src/styles.css b/packages/chat-ui/src/styles.css
index efd372994..758428780 100644
--- a/packages/chat-ui/src/styles.css
+++ b/packages/chat-ui/src/styles.css
@@ -3126,35 +3126,6 @@
   text-underline-offset: 2px;
 }
 
-.chat-member-stack {
-  display: flex;
-  align-items: center;
-}
-
-.member-avatar,
-.chat-member-stack-overflow {
-  display: grid;
-  place-items: center;
-  width: 1.5rem;
-  height: 1.5rem;
-  flex-shrink: 0;
-  border-radius: 0;
-  border: 1.5px solid var(--background);
-  margin-left: -0.35rem;
-  font-size: 0.625rem;
-  font-weight: 700;
-  line-height: 1;
-}
-
-.member-avatar:first-child {
-  margin-left: 0;
-}
-
-.chat-member-stack-overflow {
-  background: var(--muted);
-  color: var(--muted-foreground);
-}
-
 /* Settings sits apart from the quiet New routine / Insights pair — a hairline
    divider keeps it reading as the header's one persistent, always-available
    control rather than a third peer in that group. */
@@ -3166,40 +3137,6 @@
   border-left: 1px solid var(--border);
 }
 
-/* Who's live in this workbench right now, beyond the static member stack
-   above — round (vs. the member stack's square avatars) and colored per
-   principal (server-assigned, see @corbits/presence) so "live" reads at a
-   glance without any extra chrome or a status dot. */
-.chat-presence-stack {
-  display: flex;
-  align-items: center;
-  margin-left: 0.35rem;
-}
-
-.chat-presence-avatar,
-.chat-presence-stack-overflow {
-  display: grid;
-  place-items: center;
-  width: 1.5rem;
-  height: 1.5rem;
-  flex-shrink: 0;
-  border-radius: 50%;
-  border: 1.5px solid var(--background);
-  margin-left: -0.35rem;
-  font-size: 0.625rem;
-  font-weight: 700;
-  line-height: 1;
-}
-
-.chat-presence-avatar:first-child {
-  margin-left: 0;
-}
-
-.chat-presence-stack-overflow {
-  background: var(--muted);
-  color: var(--muted-foreground);
-}
-
 /* Message body column: bubble/parts + reaction/pin row share one flex
    column so chips sit under the bubble instead of as a loose sibling of
    the whole header+bubble cluster (CL-6661). Each direct child is a
diff --git a/packages/chat-ui/src/workbench-presence.ts b/packages/chat-ui/src/workbench-presence.ts
deleted file mode 100644
index 2ff07464e..000000000
--- a/packages/chat-ui/src/workbench-presence.ts
+++ /dev/null
@@ -1,117 +0,0 @@
-// A workbench's live "who's here" roster, driven off the same `/stream`
-// connection as every other live update (CL-6328) — 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/packages/chat-ui/test/chat-members.test.tsx b/packages/chat-ui/test/chat-members.test.tsx
new file mode 100644
index 000000000..f33490d6b
--- /dev/null
+++ b/packages/chat-ui/test/chat-members.test.tsx
@@ -0,0 +1,186 @@
+import { afterEach, expect, test } from "bun:test";
+import { act } from "react";
+import { createRoot } from "react-dom/client";
+import { ChatMembers } from "../src/chat-members";
+
+const container = document.createElement("div");
+let root: ReturnType<typeof createRoot>;
+afterEach(() => {
+  act(() => root.unmount());
+  container.remove();
+});
+
+function mount(overrides: Partial<Parameters<typeof ChatMembers>[0]> = {}) {
+  document.body.appendChild(container);
+  root = createRoot(container);
+  act(() =>
+    root.render(
+      <ChatMembers
+        members={[
+          {
+            key: "myra@agents.example",
+            initials: "",
+            label: "Myra",
+            tone: "agent",
+          },
+          { key: "prn_alice", initials: "A", label: "Alice", tone: "neutral" },
+        ]}
+        agents={[
+          {
+            address: "myra@agents.example",
+            handle: "myra",
+            definitionId: "def_myra",
+            definitionAssetId: "asset_myra",
+            displayName: "Myra",
+          },
+        ]}
+        currentUserPrincipalId="prn_alice"
+        onInvite={() => {}}
+        onEditAgent={() => {}}
+        {...overrides}
+      />,
+    ),
+  );
+  click("2 members");
+}
+
+function button(label: string) {
+  const match = Array.from(document.querySelectorAll("button")).find(
+    (node) =>
+      node.getAttribute("aria-label") === label ||
+      node.textContent?.trim() === label,
+  );
+  if (match === undefined) throw new Error(`Missing button: ${label}`);
+  return match;
+}
+function click(label: string) {
+  const match = Array.from(
+    document.querySelectorAll("button, [role='menuitem']"),
+  ).find(
+    (node) =>
+      node.getAttribute("aria-label") === label ||
+      node.textContent?.trim() === label,
+  );
+  if (!(match instanceof HTMLElement)) {
+    throw new Error(`Missing clickable control: ${label}`);
+  }
+  act(() => match.click());
+}
+function actions() {
+  act(() =>
+    button("Actions for Myra").dispatchEvent(
+      new PointerEvent("pointerdown", { bubbles: true, button: 0 }),
+    ),
+  );
+}
+
+test("shows counts, identities, self label, and closes the action menu on Escape", () => {
+  mount();
+  expect(container.textContent).toContain("1 person · 1 agent");
+  expect(container.textContent).toContain("Alice");
+  expect(container.textContent).toContain("You");
+  expect(
+    container.querySelector('[aria-label="Actions for Alice"]'),
+  ).toBeNull();
+  actions();
+  expect(document.querySelector('[role="menu"]')).not.toBeNull();
+  expect(document.querySelector("summary")).toBeNull();
+  expect(
+    Array.from(document.querySelectorAll('[role="menuitem"]')).some(
+      (item) => item.textContent?.trim() === "Remove",
+    ),
+  ).toBe(false);
+  const menu = document.querySelector('[role="menu"]');
+  expect(menu).not.toBeNull();
+  act(() =>
+    menu?.dispatchEvent(
+      new KeyboardEvent("keydown", { key: "Escape", bubbles: true }),
+    ),
+  );
+  expect(container.querySelector("section")).not.toBeNull();
+  expect(document.querySelector('[role="menu"]')).toBeNull();
+});
+
+test("keeps trigger avatars equal and highlights each member row", () => {
+  mount();
+
+  const triggerAvatars = Array.from(
+    container.querySelectorAll(".member-avatar"),
+  );
+  expect(triggerAvatars).toHaveLength(2);
+  expect(
+    triggerAvatars.every((avatar) => avatar.classList.contains("size-6")),
+  ).toBe(true);
+  const renderedAvatars = Array.from(
+    container.querySelectorAll('.chat-member-stack [role="img"]'),
+  );
+  expect(renderedAvatars).toHaveLength(2);
+  expect(
+    renderedAvatars.every((avatar) => avatar.classList.contains("size-6")),
+  ).toBe(true);
+
+  const memberRows = Array.from(container.querySelectorAll(".chat-member-row"));
+  expect(memberRows).toHaveLength(2);
+  expect(
+    memberRows.every(
+      (row) =>
+        row.classList.contains("hover:bg-muted") &&
+        row.classList.contains("focus-within:bg-muted"),
+    ),
+  ).toBe(true);
+});
+
+test("edits by definition ID and closes before invoking the existing editor", () => {
+  let edited = "";
+  mount({
+    onEditAgent: (id) => {
+      edited = id;
+    },
+  });
+  actions();
+  expect(document.querySelector('[role="menu"]')).not.toBeNull();
+  click("Edit agent");
+  expect(edited).toBe("def_myra");
+  expect(container.querySelector("section")).toBeNull();
+});
+
+test("opens the existing invite flow and preserves fixed-chat controls", () => {
+  let invited = false;
+  mount({
+    onInvite: () => {
+      invited = true;
+    },
+  });
+  expect(container.textContent).not.toContain("Remove");
+  click("Add member");
+  expect(invited).toBe(true);
+  expect(container.querySelector("section")).toBeNull();
+});
+
+test("does not offer unavailable invite or unresolved agent editing", () => {
+  mount({ onInvite: undefined, agents: [] });
+  expect(container.textContent).not.toContain("Add member");
+  expect(document.querySelector('[aria-label="Actions for Myra"]')).toBeNull();
+});
+
+test("does not offer actions for the native owner", () => {
+  mount({
+    currentUserPrincipalId: "prn_bob",
+    members: [
+      {
+        key: "myra@agents.example",
+        initials: "",
+        label: "Myra",
+        tone: "agent",
+      },
+      {
+        key: "prn_alice",
+        initials: "A",
+        label: "Alice",
+        tone: "neutral",
+      },
+    ],
+  });
+  expect(container.textContent).toContain("Alice");
+  expect(document.querySelector('[aria-label="Actions for Alice"]')).toBeNull();
+});
diff --git a/packages/chat-ui/test/chat-workspace.test.tsx b/packages/chat-ui/test/chat-workspace.test.tsx
index abd00694a..6db38af05 100644
--- a/packages/chat-ui/test/chat-workspace.test.tsx
+++ b/packages/chat-ui/test/chat-workspace.test.tsx
@@ -2007,7 +2007,7 @@ describe("Workbench header polish (CL-6106)", () => {
     harness.unmount();
   });
 
-  test("agent participant chips live in the square member stack, naming the agent by display name (CL-6424 supersedes the raw-handle tooltip)", async () => {
+  test("member preview names the agent by display name", async () => {
     stubFetch(undefined, WORKBENCH_WITH_AGENT_WIRE);
     const harness = await mount({
       tenant: { kind: "ready", tenantId: "tnt_1" },
@@ -2254,7 +2254,7 @@ describe("Invite control visibility (CL-6781)", () => {
     harness.unmount();
   });
 
-  test("shows Invite agent once at least one definition is invitable", async () => {
+  test("offers Add member in the popover once a definition is invitable", async () => {
     globalThis.EventSource = StubEventSource as unknown as typeof EventSource;
     globalThis.fetch = (async (
       input: RequestInfo | URL,
@@ -2308,7 +2308,12 @@ describe("Invite control visibility (CL-6781)", () => {
     await harness.settle();
     await harness.settle();
 
-    expect(harness.container.textContent).toContain("Invite agent");
+    const trigger = harness.container.querySelector<HTMLButtonElement>(
+      'button[aria-controls][aria-label$="members"]',
+    );
+    expect(trigger).not.toBeNull();
+    act(() => trigger?.click());
+    expect(harness.container.textContent).toContain("Add member");
     harness.unmount();
   });
 });
diff --git a/packages/chat-ui/test/presence-stack.test.tsx b/packages/chat-ui/test/presence-stack.test.tsx
deleted file mode 100644
index 23645ba77..000000000
--- a/packages/chat-ui/test/presence-stack.test.tsx
+++ /dev/null
@@ -1,222 +0,0 @@
-// The workbench header's live who's-here stack (CL-5958), now driven off
-// the workbench's own `/stream` connection (CL-6328) rather than a plain
-// `presenceMembers` prop: nothing rendered until a `chat.presence.snapshot`
-// arrives, one avatar per member from there, colored deterministically per
-// principal. Mirrors chat-workspace.test.tsx's stub-fetch/mount harness.
-
-import { afterEach, describe, expect, test } from "bun:test";
-import { act, createElement } from "react";
-import { createRoot } from "react-dom/client";
-import type { Root } from "react-dom/client";
-import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
-
-const realFetch = globalThis.fetch;
-const realEventSource = globalThis.EventSource;
-
-class StubEventSource {
-  static instances: StubEventSource[] = [];
-  onopen: (() => void) | null = null;
-  onerror: (() => void) | null = null;
-  readyState = 1;
-  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);
-  }
-
-  close() {
-    this.readyState = 2;
-  }
-}
-
-afterEach(() => {
-  globalThis.fetch = realFetch;
-  globalThis.EventSource = realEventSource;
-  StubEventSource.instances = [];
-});
-
-const WORKBENCH_WIRE = {
-  id: "ch_1",
-  title: "Launch Planning",
-  kind: "workbench",
-  pinned: false,
-  participants: [] as { address: string; handle: string }[],
-};
-
-function stubFetch() {
-  globalThis.EventSource = StubEventSource as unknown as typeof EventSource;
-  globalThis.fetch = (async (input: RequestInfo | URL) => {
-    const path = typeof input === "string" ? input : String(input);
-    const json = (body: unknown) =>
-      new Response(JSON.stringify(body), {
-        status: 200,
-        headers: { "content-type": "application/json" },
-      });
-    if (/\/chat\/workbenches\?kind=workbench$/.test(path)) {
-      return json({ items: [WORKBENCH_WIRE] });
-    }
-    if (/\/chat\/workbenches\?kind=chat$/.test(path))
-      return json({ items: [] });
-    if (/\/chat\/workbenches\/[^/]+\/threads$/.test(path)) {
-      return json({ rootThreadId: "", items: [] });
-    }
-    if (/\/chat\/workbenches\/[^/]+\/messages/.test(path))
-      return json({ items: [] });
-    if (/\/chat\/workbenches\/[^/]+\/read-state$/.test(path)) return json({});
-    if (/\/chat\/workbenches\/[^/]+\/invitable$/.test(path))
-      return json({ items: [] });
-    throw new Error(`unstubbed fetch: ${path}`);
-  }) as typeof fetch;
-}
-
-const { ChatWorkspace, TEAM_AVATAR_STACK_LIMIT } =
-  await import("../src/chat-workspace");
-
-const sleep = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));
-
-function mount(props: Parameters<typeof ChatWorkspace>[0]) {
-  const container = document.createElement("div");
-  document.body.appendChild(container);
-  const root: Root = createRoot(container);
-  const queryClient = new QueryClient({
-    defaultOptions: { queries: { retry: false, gcTime: 0, staleTime: 0 } },
-  });
-  act(() => {
-    root.render(
-      createElement(
-        QueryClientProvider,
-        { client: queryClient },
-        createElement(ChatWorkspace, props),
-      ),
-    );
-  });
-  return {
-    container,
-    settle: () => act(() => sleep(30)),
-    unmount: () => root.unmount(),
-  };
-}
-
-function firstStream(): StubEventSource {
-  const instance = StubEventSource.instances[0];
-  if (instance === undefined) throw new Error("no stream connected");
-  return instance;
-}
-
-describe("workbench header presence stack", () => {
-  test("renders nothing before a presence snapshot arrives", async () => {
-    stubFetch();
-    const harness = mount({
-      tenant: { kind: "ready", tenantId: "tnt_1" },
-      workbenchId: "ch_1",
-    });
-    await harness.settle();
-
-    expect(harness.container.querySelector(".chat-presence-stack")).toBeNull();
-    harness.unmount();
-  });
-
-  test("renders one colored avatar per member in the stream's presence snapshot", async () => {
-    stubFetch();
-    const harness = mount({
-      tenant: { kind: "ready", tenantId: "tnt_1" },
-      workbenchId: "ch_1",
-    });
-    await harness.settle();
-
-    act(() => {
-      firstStream().emit("chat.presence.snapshot", {
-        members: [
-          { principalId: "prn_alice", lastActiveAt: "2026-01-01T00:00:00Z" },
-          { principalId: "prn_bob", lastActiveAt: "2026-01-01T00:00:00Z" },
-        ],
-      });
-    });
-    await harness.settle();
-
-    const avatars = harness.container.querySelectorAll(".chat-presence-avatar");
-    expect(avatars).toHaveLength(2);
-    expect(
-      harness.container.querySelector(".chat-presence-stack"),
-    ).not.toBeNull();
-    expect(harness.container.querySelector(".chat-member-stack")).toBeNull();
-    harness.unmount();
-  });
-
-  test("chat.presence deltas add and remove members without a snapshot", async () => {
-    stubFetch();
-    const harness = mount({
-      tenant: { kind: "ready", tenantId: "tnt_1" },
-      workbenchId: "ch_1",
-    });
-    await harness.settle();
-
-    act(() => {
-      firstStream().emit("chat.presence", {
-        principalId: "prn_alice",
-        state: "online",
-        lastActiveAt: "2026-01-01T00:00:00Z",
-      });
-    });
-    await harness.settle();
-    expect(
-      harness.container.querySelectorAll(".chat-presence-avatar"),
-    ).toHaveLength(1);
-
-    act(() => {
-      firstStream().emit("chat.presence", {
-        principalId: "prn_alice",
-        state: "offline",
-        lastActiveAt: "2026-01-01T00:01:00Z",
-      });
-    });
-    await harness.settle();
-    expect(
-      harness.container.querySelectorAll(".chat-presence-avatar"),
-    ).toHaveLength(0);
-    harness.unmount();
-  });
-
-  test("collapses anything past the member-stack limit into a +N chip", async () => {
-    stubFetch();
-    const harness = mount({
-      tenant: { kind: "ready", tenantId: "tnt_1" },
-      workbenchId: "ch_1",
-    });
-    await harness.settle();
-
-    const liveCount = TEAM_AVATAR_STACK_LIMIT + 4;
-    act(() => {
-      firstStream().emit("chat.presence.snapshot", {
-        members: Array.from({ length: liveCount }, (_, index) => ({
-          principalId: `prn_${String(index)}`,
-          lastActiveAt: "2026-01-01T00:00:00Z",
-        })),
-      });
-    });
-    await harness.settle();
-
-    expect(
-      harness.container.querySelectorAll(".chat-presence-avatar"),
-    ).toHaveLength(TEAM_AVATAR_STACK_LIMIT);
-    const overflow = harness.container.querySelector(
-      ".chat-presence-stack-overflow",
-    );
-    expect(overflow).not.toBeNull();
-    expect(overflow?.textContent).toBe("+4");
-    harness.unmount();
-  });
-});
diff --git a/packages/chat-ui/test/team-avatar-stack.test.tsx b/packages/chat-ui/test/team-avatar-stack.test.tsx
index 57847e697..8d96aabdb 100644
--- a/packages/chat-ui/test/team-avatar-stack.test.tsx
+++ b/packages/chat-ui/test/team-avatar-stack.test.tsx
@@ -1,8 +1,7 @@
 // The workbench header's static member stack: every agent participant on
-// the workbench plus every human on the roster, square avatars, collapsing
-// anything past TEAM_AVATAR_STACK_LIMIT into a "+N" chip. Live presence is
-// a separate round stack (see presence-stack.test.tsx).
-// Mirrors presence-stack.test.tsx's stub-fetch/mount harness.
+// the workbench plus every human on the roster, a compact avatar preview
+// alongside the full member count. The member control is the only header
+// identity surface; live presence must not add another avatar stack.
 
 import { afterEach, describe, expect, test } from "bun:test";
 import { act, createElement } from "react";
@@ -125,12 +124,6 @@ function mount(props: Parameters<typeof ChatWorkspace>[0]) {
   };
 }
 
-function firstStream(): StubEventSource {
-  const instance = StubEventSource.instances[0];
-  if (instance === undefined) throw new Error("no stream connected");
-  return instance;
-}
-
 /** A human participant whose bare address (no `@`, so `isAgentAddress`
  * reads it as human) IS its own principal id — this is what lets the
  * presence roster's bare `principalId` resolve back to a display name
@@ -140,7 +133,7 @@ function humanParticipant(principalId: string, handle: string) {
 }
 
 describe("workbench header member avatar stack", () => {
-  test("renders every agent participant and every roster human in the square member stack", async () => {
+  test("previews agent and human membership without a duplicate live stack", async () => {
     stubFetch({
       participants: [
         { address: "myra@agents.example", handle: "Myra" },
@@ -152,14 +145,6 @@ describe("workbench header member avatar stack", () => {
       workbenchId: "ch_1",
     });
     await harness.settle();
-    act(() => {
-      firstStream().emit("chat.presence.snapshot", {
-        members: [
-          { principalId: "prn_alice", lastActiveAt: "2026-01-01T00:00:00Z" },
-        ],
-      });
-    });
-    await harness.settle();
 
     const memberStack = harness.container.querySelector(".chat-member-stack");
     expect(memberStack).not.toBeNull();
@@ -176,13 +161,10 @@ describe("workbench header member avatar stack", () => {
     expect(agentAvatar.querySelector('[data-corbit="true"]')).not.toBeNull();
     expect(memberHumans).toHaveLength(1);
     expect((memberHumans[0] as HTMLElement).title).toBe("Alice");
-    const liveStack = harness.container.querySelector(".chat-presence-stack");
-    expect(liveStack).not.toBeNull();
-    const liveAvatars = harness.container.querySelectorAll(
-      ".chat-presence-avatar",
-    );
-    expect(liveAvatars).toHaveLength(1);
-    expect((liveAvatars[0] as HTMLElement).title).toBe("Alice");
+    expect(harness.container.querySelector(".chat-presence-stack")).toBeNull();
+    expect(
+      harness.container.querySelectorAll(".chat-presence-avatar"),
+    ).toHaveLength(0);
     expect(
       harness.container.querySelector(".chat-member-stack-overflow"),
     ).toBeNull();
@@ -243,7 +225,7 @@ describe("workbench header member avatar stack", () => {
     harness.unmount();
   });
 
-  test("collapses anything past the limit into a +N chip", async () => {
+  test("shows the full member count with a compact avatar preview", async () => {
     const humanNames = ["Alice", "Bob", "Carla", "Dana", "Eve", "Finn"];
     const humanParticipants = humanNames.map((name, index) =>
       humanParticipant(`prn_${index}`, name),
@@ -259,29 +241,16 @@ describe("workbench header member avatar stack", () => {
       workbenchId: "ch_1",
     });
     await harness.settle();
-    act(() => {
-      firstStream().emit("chat.presence.snapshot", {
-        members: humanNames.map((_, index) => ({
-          principalId: `prn_${index}`,
-          lastActiveAt: "2026-01-01T00:00:00Z",
-        })),
-      });
-    });
-    await harness.settle();
-
-    // 1 agent + 6 humans = 7 total, limit is 6, so one overflows.
-    const overflow = harness.container.querySelector(
-      ".chat-member-stack-overflow",
+    expect(harness.container.querySelectorAll(".member-avatar")).toHaveLength(
+      2,
     );
-    expect(overflow).not.toBeNull();
-    expect(overflow?.textContent).toBe("+1");
+    expect(
+      harness.container.querySelector('button[aria-label="7 members"]'),
+    ).not.toBeNull();
     harness.unmount();
   });
 
-  test("own presence avatar uses currentUser.name, never Member (CL-6655)", async () => {
-    // The signed-in reader is live in presence but not yet on the workbench
-    // participants list (or has no handle there) — without currentUser.name
-    // the stack title falls back to "Member".
+  test("does not render a duplicate live avatar (CL-6655)", async () => {
     stubFetch({
       participants: [{ address: "myra@agents.example", handle: "Myra" }],
     });
@@ -291,22 +260,11 @@ describe("workbench header member avatar stack", () => {
       currentUser: { principalId: "prn_self", name: "sawyer" },
     });
     await harness.settle();
-    act(() => {
-      firstStream().emit("chat.presence.snapshot", {
-        members: [
-          { principalId: "prn_self", lastActiveAt: "2026-01-01T00:00:00Z" },
-        ],
-      });
-    });
-    await harness.settle();
 
-    const presenceAvatars = harness.container.querySelectorAll(
-      ".chat-presence-avatar",
-    );
-    expect(presenceAvatars).toHaveLength(1);
-    expect((presenceAvatars[0] as HTMLElement).title).toBe("sawyer");
-    expect((presenceAvatars[0] as HTMLElement).title).not.toBe("Member");
-    expect(presenceAvatars[0]?.textContent).toBe("S");
+    expect(harness.container.querySelector(".chat-presence-stack")).toBeNull();
+    expect(
+      harness.container.querySelectorAll(".chat-presence-avatar"),
+    ).toHaveLength(0);
     harness.unmount();
   });
 
diff --git a/packages/chat-ui/test/workbench-presence.test.ts b/packages/chat-ui/test/workbench-presence.test.ts
deleted file mode 100644
index 38d42b21b..000000000
--- a/packages/chat-ui/test/workbench-presence.test.ts
+++ /dev/null
@@ -1,110 +0,0 @@
-// Pure-logic tests for the who's-here roster's state machine (CL-6328):
-// `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 "../src/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/packages/chat/src/routes.ts b/packages/chat/src/routes.ts
index 92c1cd595..f00bfc83c 100644
--- a/packages/chat/src/routes.ts
+++ b/packages/chat/src/routes.ts
@@ -942,31 +942,44 @@ const MoveWorkbenchBody = type({
 
 export { findExistingAgentChat };
 
-/** Annotates a workbench view with its native child-tenancy — the
- * `tenancy` field every workbench created after this rollout carries,
- * never `null` unless a caller reaches a route that skips the
- * annotation (there are none; `GET /workbenches` handles the one place a
- * link can be legitimately missing itself, via its own `legacy`
- * branch). */
-function withTenancy(
-  view: ReturnType<typeof workbenchView>,
-  link: { tenantId: string; parentTenantId: string; slug: string },
-): ReturnType<typeof workbenchView> & {
-  tenancy: { tenantId: string; parentTenantId: string; slug: string };
-  legacy: false;
-} {
-  return {
-    ...view,
-    tenancy: {
-      tenantId: link.tenantId,
-      parentTenantId: link.parentTenantId,
-      slug: link.slug,
-    },
-    legacy: false,
-  };
-}
-
 export function createChatRoutes(deps: CreateChatRoutesDeps): Hono<TenantEnv> {
+  async function withTenancy(
+    view: ReturnType<typeof workbenchView>,
+    link: { tenantId: string; parentTenantId: string; slug: string },
+    owningTenantId: string,
+  ) {
+    const ownerUserId = await deps.tenancy.getWorkbenchOwnerUserId(
+      link.tenantId,
+    );
+    const ownerPrincipal =
+      ownerUserId === undefined
+        ? undefined
+        : await deps.tenancy.getTenantPrincipalByRefId(
+            owningTenantId,
+            ownerUserId,
+          );
+    const owner =
+      ownerPrincipal?.kind === "user" && ownerPrincipal.status === "active"
+        ? {
+            address: ownerPrincipal.id,
+            handle:
+              (await deps.resolvePrincipalName?.(
+                owningTenantId,
+                ownerPrincipal.id,
+              )) ?? "Member",
+          }
+        : null;
+    return {
+      ...view,
+      tenancy: {
+        tenantId: link.tenantId,
+        parentTenantId: link.parentTenantId,
+        slug: link.slug,
+      },
+      legacy: false,
+      owner,
+    };
+  }
   const app = new Hono<TenantEnv>();
   const registry =
     deps.workbenchSubscribers ?? createWorkbenchSubscriberRegistry();
@@ -1053,7 +1066,7 @@ export function createChatRoutes(deps: CreateChatRoutesDeps): Hono<TenantEnv> {
           );
           return c.json(
             link !== undefined
-              ? withTenancy(workbenchView(existing), link)
+              ? await withTenancy(workbenchView(existing), link, tenant.id)
               : { ...workbenchView(existing), tenancy: null, legacy: true },
             200,
           );
@@ -1309,9 +1322,10 @@ export function createChatRoutes(deps: CreateChatRoutesDeps): Hono<TenantEnv> {
         });
 
         return c.json(
-          withTenancy(
+          await withTenancy(
             workbenchView({ workbenchId, settings: finalSettings }),
             workbenchTenant,
+            tenant.id,
           ),
           201,
         );
@@ -1380,9 +1394,10 @@ export function createChatRoutes(deps: CreateChatRoutesDeps): Hono<TenantEnv> {
               : joined.settings;
 
           return c.json(
-            withTenancy(
+            await withTenancy(
               workbenchView({ workbenchId, settings: finalSettings }),
               workbenchTenant,
+              tenant.id,
             ),
             201,
           );
@@ -1415,7 +1430,10 @@ export function createChatRoutes(deps: CreateChatRoutesDeps): Hono<TenantEnv> {
         }
       }
 
-      return c.json(withTenancy(workbenchView(row), workbenchTenant), 201);
+      return c.json(
+        await withTenancy(workbenchView(row), workbenchTenant, tenant.id),
+        201,
+      );
     },
   );
 
@@ -1478,31 +1496,33 @@ export function createChatRoutes(deps: CreateChatRoutesDeps): Hono<TenantEnv> {
         roomMessages: deps.roomMessages,
       });
 
-      const ownItems = rows.map((row, index) => {
-        const link = links[index];
-        const view =
-          link !== undefined
-            ? withTenancy(workbenchView(row), link)
-            : { ...workbenchView(row), tenancy: null, legacy: true };
-        const activity = activityByWorkbenchId[row.workbenchId];
-        const withLiveState = {
-          ...view,
-          live: liveState.get(row.workbenchId),
-        };
-        if (activity === undefined) return withLiveState;
-        const withUnread = {
-          ...withLiveState,
-          unreadCount: activity.unreadCount,
-        };
-        if (activity.lastActivityAt === undefined) return withUnread;
-        const withActivity = {
-          ...withUnread,
-          lastActivityAt: activity.lastActivityAt,
-        };
-        return activity.preview === undefined
-          ? withActivity
-          : { ...withActivity, preview: activity.preview };
-      });
+      const ownItems = await Promise.all(
+        rows.map(async (row, index) => {
+          const link = links[index];
+          const view =
+            link !== undefined
+              ? await withTenancy(workbenchView(row), link, tenant.id)
+              : { ...workbenchView(row), tenancy: null, legacy: true };
+          const activity = activityByWorkbenchId[row.workbenchId];
+          const withLiveState = {
+            ...view,
+            live: liveState.get(row.workbenchId),
+          };
+          if (activity === undefined) return withLiveState;
+          const withUnread = {
+            ...withLiveState,
+            unreadCount: activity.unreadCount,
+          };
+          if (activity.lastActivityAt === undefined) return withUnread;
+          const withActivity = {
+            ...withUnread,
+            lastActivityAt: activity.lastActivityAt,
+          };
+          return activity.preview === undefined
+            ? withActivity
+            : { ...withActivity, preview: activity.preview };
+        }),
+      );
 
       // Workbenches a sibling tenant projected into this one (CL-5882) —
       // a UNION with this tenant's own rows above, never a replacement.
diff --git a/packages/chat/test/workbench-owner.test.ts b/packages/chat/test/workbench-owner.test.ts
new file mode 100644
index 000000000..1e62c2554
--- /dev/null
+++ b/packages/chat/test/workbench-owner.test.ts
@@ -0,0 +1,39 @@
+import { expect, test } from "bun:test";
+import { createChatRoutes } from "../src/routes";
+import { createInMemoryWorkbenchTenancyStore } from "../src/workbench-tenancy";
+import { buildDeps, createWorkbench, mountAs, TENANT } from "./test-support";
+
+test("the native owner is projected identically for owner and nonmember viewers", async () => {
+  const tenancy = createInMemoryWorkbenchTenancyStore();
+  tenancy.registerPrincipal(TENANT.id, {
+    id: "prn_alice",
+    refId: "prn_alice",
+    kind: "user",
+    status: "active",
+  });
+  const deps = buildDeps({
+    tenancy,
+    resolvePrincipalName: async () => "Alice",
+  });
+  const routes = createChatRoutes(deps);
+  const alice = mountAs(routes, "prn_alice");
+  await createWorkbench(alice, { kind: "workbench" });
+  for (const viewer of [alice, mountAs(routes, "prn_bob")]) {
+    const response = await viewer.request("/workbenches?kind=workbench");
+    expect(response.status).toBe(200);
+    expect(await response.json()).toMatchObject({
+      items: [
+        { owner: { address: "prn_alice", handle: "Alice" }, participants: [] },
+      ],
+    });
+  }
+});
+
+test("an unresolved owner does not invent a participant", async () => {
+  const app = mountAs(createChatRoutes(buildDeps()), "prn_alice");
+  await createWorkbench(app, { kind: "workbench" });
+  const response = await app.request("/workbenches?kind=workbench");
+  expect(await response.json()).toMatchObject({
+    items: [{ owner: null, participants: [] }],
+  });
+});