Merge branch 'stack/agent-profiles-3-wire' into stack/agent-profiles-5-web-ui

recompose becomes a parent re-link: the new preset's standing mount is
ensured BEFORE the link moves, so a failed switch leaves the agent exactly as
it was — the unmount-then-restore dance (and unmountPresetFor with it) is
gone, and the restore-failure test now asserts the agent KEEPS its tools with
the source directory deleted, because the standing mount is not the file.

docs/cordis-catalog/services.md

@@ -68,14 +68,16 @@ async list(): Promise<AgentPreset[]>
 async resolve(id?: string): Promise<AgentPreset>
 
 /**
- * Compose one agent from a preset, installing it under that agent alone.
+ * Compose one agent from a preset: ensure the preset's standing mount, then
+ * parent the agent's scope key to it so the mount's registrations and
+ * listeners cover this agent.
  *
  * Call from the agent factory's `setup(agentCtx)`; a rejection there rolls
  * the agent creation back, so a broken preset never yields a half-composed
  * session.
  * @param agentCtx - the agent's scope context.
  * @param id - the preset id, or `undefined` for {@link defaultId}.
- * @returns the preset that was mounted, for the caller to record.
+ * @returns the preset that was composed, for the caller to record.
  * @throws when the preset is unknown or its composition is unusable.
  */
 async mount(agentCtx: Context, id?: string): Promise<AgentPreset>
@@ -98,26 +100,42 @@ async mount(agentCtx: Context, id?: string): Promise<AgentPreset>
 serviceFor<K extends string & keyof Context>(agent: { ctx: Context }, name: K): Context[K] | undefined
 
 /**
- * Replace the composition installed for one agent.
+ * Re-link one agent to a different preset's standing composition.
  *
  * Only valid while the agent has produced nothing: swapping tools mid
- * conversation would leave logged tool calls the new composition cannot make.
- * The CALLER owns that check — this method does not read session history.
+ * conversation would leave logged tool calls the new composition cannot
+ * make. The CALLER owns that check — this method does not read session
+ * history.
  *
- * The swap is unmount-then-mount because two compositions cannot coexist:
- * both would register the same tool names into one layer. A failed mount
- * therefore restores the previous composition rather than leaving the agent
- * with nothing.
+ * The swap is a parent re-link, not an unmount: standing mounts are shared
+ * and permanent, so the old composition stays for its other agents and the
+ * new one is ensured BEFORE the link moves. An unknown or unusable preset
+ * therefore throws with the agent exactly as it was — there is no torn-down
+ * state to restore.
  * @param agentCtx - the agent's scope context.
  * @param id - the preset to compose the agent from instead.
  * @returns the preset now installed.
- * @throws when the preset is unknown or its composition is unusable; the
- * previous composition is restored first.
+ * @throws when the preset is unknown or its composition is unusable.
  */
 async recompose(agentCtx: Context, id: string): Promise<AgentPreset>
+
+/**
+ * The standing scope key of one preset, for a host reader with no agent.
+ *
+ * A cold transcript read resolves tool presenters against the composition
+ * the session recorded, and the standing mount makes that possible without
+ * resuming anything: ensuring the mount composes plugins but starts no
+ * agent, no session, and no turn.
+ * @param id - the preset id, or `undefined` for {@link defaultId}.
+ * @returns the standing scope key readers pass as a registry view scope.
+ * @throws when the preset is unknown or its composition is unusable.
+ */
+async standingKeyFor(id?: string): Promise<ScopeKey>
 ```
 
-Source: [`packages/preset/agent-presets/src/index.ts:57`](../../packages/preset/agent-presets/src/index.ts)
+Types: [ScopeKey](../core-data-structures/scope.md)
+
+Source: [`packages/preset/agent-presets/src/index.ts:68`](../../packages/preset/agent-presets/src/index.ts)
 
 ## `ctx.agents` — `AgentRegistry`