Port Pi extension UI, commands, and model settings to the RPC bridge

apps/server/src/services/skills/builtin-skills/bb-cli/SKILL.md

@@ -342,6 +342,11 @@ environment pull-request show <id>`. Diff commands require an explicit target
   (alias `--host`) or `--environment <id>` to inspect the machine where work
   will run; the selectors cannot be combined. With neither selector they
   intentionally inspect the primary machine.
+- Pi's native cycling preference is available through `bb pi models list`,
+  `bb pi models set <model-id...>`, and `bb pi models enable-all`. Each accepts
+  optional `--machine <id-or-name>` and `--json`; without a machine it targets
+  the primary host. These commands update Pi's global `enabledModels` and do
+  not accept a cwd.
 - Known ACP agents can appear automatically when their CLI is installed on the
   host; for example `opencode`, `omp`, Grok Build's `grok` CLI, or Hermes'
   `hermes` CLI on PATH appears as provider `acp-opencode`, `acp-omp`,

docs/configuration.md

@@ -384,6 +384,35 @@ so a configured agent shows the generic tool glyph, and bb drops the field when
 it reads the old array. A setting entry wins over a config entry with the same
 `id`.
 
+## Pi enabled models
+
+Settings → Plugins → Pi provider → Models edits Pi's global `enabledModels` on
+the primary machine. The editor lists authenticated models, supports search
+and per-model switches, and updates BB's picker and model cycling immediately
+after Save. **Enable all** removes the native preference; **Reset** restores the
+last saved selection.
+
+For CLI use:
+
+```sh
+bb pi models list [--machine <id-or-name>] [--json]
+bb pi models set <model-id...> [--machine <id-or-name>] [--json]
+bb pi models enable-all [--machine <id-or-name>] [--json]
+```
+
+Without `--machine`, the command targets the primary machine. SDK clients call
+the Pi plugin through `sdk.plugins.callRpc` with plugin id `provider-pi` and
+method `readModelSettings` or `writeModelSettings`; each input carries
+`hostId`, writes also carry `enabledModelIds` (`string[]` or `null`), and the
+call supplies an `outputSchema` for the snapshot as required by
+`sdk.plugins.callRpc`. Neither CLI nor SDK accepts a cwd because this editor
+changes Pi's global
+preference, not a workspace settings file.
+
+This preference controls ordinary picker/cycling visibility, not execution
+authorization. A model already selected by a thread remains available as a
+selected-only model.
+
 ## Custom Models
 
 Register extra picker models by editing top-level `customModels` in

docs/model-preferences-policy.md

@@ -0,0 +1,102 @@
+# Provider-native model preferences
+
+Status: accepted and implemented for Pi
+
+## Decision
+
+Pi's global `enabledModels` setting remains the authority for Pi's preferred
+model set. BB exposes a product editor for that native preference; it does not
+create a second BB model-policy document.
+
+The editor lists authenticated models on the host selected by Settings. It
+shows model switches, search, enabled count, **Enable all**, **Reset**, and
+**Save**. Host routing is supplied by the Settings host context. The editor
+never asks for a machine, cwd, file path, pattern, revision, or conflict
+resolution.
+
+The CLI offers the same global operation through `bb pi models`; its optional
+`--machine` flag follows BB's remote-targeting convention. SDK clients use the
+Pi plugin's `readModelSettings` and `writeModelSettings` RPC methods through
+`sdk.plugins.callRpc`. Neither surface accepts cwd.
+
+## Invariants
+
+### Preferences are not authorization
+
+`enabledModels` controls Pi's picker and model cycling. It does not authorize
+execution. A selected thread model outside the preferred set remains in BB's
+selected-only catalog and can continue to run.
+
+A future execution restriction would be a separate BB-owned policy with an
+explicit denial result. It must not reuse this preference.
+
+### Pi owns matching
+
+Pi model identifiers and `enabledModels` patterns are opaque outside the Pi
+bridge. The bridge uses Pi's native resolver, including ordered patterns,
+globs, bare IDs, aggregator IDs containing slashes or colons, and thinking
+suffixes. Core model contracts carry only ordinary model IDs and never gain Pi
+pattern fields.
+
+The product editor intentionally writes exact authenticated model IDs. Existing
+native patterns are resolved internally to switch state but are never exposed
+or rewritten until the user saves a changed selection.
+
+### Empty resolution is unrestricted
+
+Pi treats absent or empty `enabledModels` as unrestricted. It also treats a
+configured pattern set that resolves no models as unrestricted rather than
+deny-all. BB preserves that behavior: the picker cannot become empty because a
+stale native pattern stopped matching.
+
+**Enable all** removes the global `enabledModels` field. The editor prevents a
+user from disabling the final authenticated model.
+
+### Selected-only models remain available
+
+Model discovery partitions the authenticated catalog:
+
+- models selected by Pi's native preference appear in `models`, in Pi's
+  resolved order;
+- authenticated models outside that preference appear in
+  `selectedOnlyModels`;
+- duplicate IDs are not introduced.
+
+The distinction preserves an existing thread's selection without presenting
+that model during ordinary cycling.
+
+### Hosts are isolated
+
+The selected host determines credentials, authenticated models, and the global
+Pi settings file. A host with no authenticated models reports that state; it
+must never show another host's cached catalog.
+
+Saving clears the server's model-catalog memo and broadcasts a model change so
+web and mobile picker queries refetch immediately. The Pi bridge reloads native
+settings before every model-list resolution, so a save does not require a BB
+restart.
+
+### Writes preserve the settings document
+
+The Pi bridge updates only global `enabledModels`. It takes the same
+host-local lock Pi uses (`proper-lockfile` on the settings path), preserves
+unrelated JSON fields and file mode, writes a temporary file beside the real
+file (through a symlinked `settings.json`, not over the link), and atomically
+renames it over the settings file. Invalid settings or write failures fail the
+save rather than replacing unknown content; a settings file pi could not load
+is reported and read as empty for listings, so the picker keeps working.
+
+The bridge reads only the global file. A project's `.pi/settings.json`
+`enabledModels` applies in pi only once the project is trusted, a decision
+the bridge cannot see, and a repository must not be able to steer the picker.
+
+## Ownership
+
+| Concern                                      | Owner                                        |
+| -------------------------------------------- | -------------------------------------------- |
+| Authenticate and enumerate Pi models         | Pi model runtime in the Pi bridge            |
+| Resolve native `enabledModels` semantics     | Pi native resolver in the Pi bridge          |
+| Atomically update global Pi settings         | Pi bridge on the selected host               |
+| Route the selected host                      | BB Settings context / CLI machine resolution |
+| Cache invalidation and client notification   | BB server provider plugin API                |
+| Search, draft, reset, save, and empty states | Pi provider plugin app                       |

packages/templates/src/templates/bb-guide-providers.md

@@ -13,6 +13,12 @@ Providers are agent backends (e.g., codex, claude-code). Each supports different
                                           List available providers
   bb provider models [providerId] [--machine <id-or-name> | --environment <id>]
                                           List models for a provider
+  bb pi models list [--machine <id-or-name>] [--json]
+                                          List authenticated Pi models and enabled state
+  bb pi models set <model-id...> [--machine <id-or-name>] [--json]
+                                          Replace Pi's global enabled models
+  bb pi models enable-all [--machine <id-or-name>] [--json]
+                                          Enable every authenticated Pi model
 
 Use these before spawning threads if you are unsure which provider or model to use.
 `--host` is an alias for `--machine`. Machine and environment selectors are

plugins/provider-pi/app.css

@@ -0,0 +1,44 @@
+.pi-extension-state {
+  display: grid;
+  gap: 0.5rem;
+  min-width: 0;
+  color: var(--foreground);
+  font-size: var(--text-xs);
+  line-height: var(--text-xs--line-height);
+}
+
+.pi-extension-state__metadata,
+.pi-extension-state__widget {
+  display: grid;
+  gap: 0.375rem;
+  min-width: 0;
+  padding: 0.625rem 0.75rem;
+  border: 1px solid var(--border);
+  border-radius: 0.625rem;
+  background: var(--surface-recessed);
+}
+
+.pi-extension-state__title {
+  overflow: hidden;
+  font-weight: 600;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.pi-extension-state__status {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  min-width: 0;
+  overflow: hidden;
+  color: var(--muted-foreground);
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.pi-extension-state__widget {
+  overflow-x: auto;
+  font-family: var(--font-mono);
+  line-height: 1.45;
+  white-space: pre;
+}