feat(web): rewrite subagent conversations for FIFO activation

packages/client/runtime/src/client/sessions/manager.ts

@@ -153,7 +153,7 @@ export class SessionManager {
   selectSubagent(address: SubagentAddress): void {
     const catalog = this.catalogs.get(address.parentSessionId)
     const entry = catalog?.entries.find(candidate => candidate.id === address.childSessionId)
-    if (entry === undefined || entry.kind !== 'child') {
+    if (entry === undefined || entry.kind !== 'child' || entry.mode !== address.mode) {
       throw new Error(`sessions.selectSubagent: ${address.childSessionId} is not a healthy catalog child`)
     }
     this.addresses.set(address.childSessionId, address)
@@ -625,7 +625,7 @@ export class SessionManager {
       case 'host/session-removed': {
         this.recordMutation({ kind: 'remove', sessionId: frame.sessionId })
         if (this.addresses.has(frame.sessionId)) {
-          // A continuable activation detaching is not durable child deletion:
+          // An Activation detaching is not durable child deletion:
           // keep the addressed conversation usable and return its catalog row
           // to the inactive state.
           this.sessions.get(frame.sessionId)?.handleRunning(false)

packages/client/runtime/src/client/sessions/service.ts

@@ -642,7 +642,7 @@ export class SessionsService implements ISessions {
       if (child?.kind === 'child') {
         byId[current] = {
           id: current,
-          displayTitle: child.label,
+          displayTitle: child.label ?? current,
           parentId: currentAddress.parentSessionId,
           origin: 'subagent',
           running: child.activity === 'running',
@@ -660,7 +660,8 @@ export class SessionsService implements ISessions {
     } else if (byId[current] !== undefined
       && (persisted !== current
         || this.selection.getSnapshot().subagentAddress?.childSessionId !== currentAddress?.childSessionId
-        || this.selection.getSnapshot().subagentAddress?.parentSessionId !== currentAddress?.parentSessionId)) {
+        || this.selection.getSnapshot().subagentAddress?.parentSessionId !== currentAddress?.parentSessionId
+        || this.selection.getSnapshot().subagentAddress?.mode !== currentAddress?.mode)) {
       this.selection.set({
         sessionId: current,
         ...(currentAddress === undefined ? {} : { subagentAddress: currentAddress }),

packages/client/runtime/src/client/sessions/session.ts

@@ -223,6 +223,15 @@ export class Session implements SessionFace {
     try {
       if (this.address === undefined) {
         result = (await this.api.sessions.prompt({ sessionId: this.sessionId, mode, content })).result
+      } else if (this.address.mode === 'one-shot') {
+        result = {
+          ok: false,
+          error: {
+            code: 'subagent-not-resumable',
+            message: 'one-shot subagent conversations are read-only',
+            details: { childSessionId: this.address.childSessionId },
+          },
+        }
       } else {
         const routed = (await this.api.subagents.prompt({ ...this.address, content })).result
         result = routed.ok ? { ok: true, value: { accepted: true } } : routed
@@ -270,7 +279,7 @@ export class Session implements SessionFace {
       const result: RpcResult<{ accepted: true }> = {
         ok: false,
         error: {
-          code: 'subagent-not-delivered',
+          code: 'subagent-delivery-unavailable',
           message: 'subagent activation cancellation is unavailable',
           details: { childSessionId: this.address.childSessionId },
         },
@@ -512,6 +521,7 @@ export class Session implements SessionFace {
   configureSubagent(address: SubagentAddress | undefined, parentAvailable = false): void {
     const same = this.address?.parentSessionId === address?.parentSessionId
       && this.address?.childSessionId === address?.childSessionId
+      && this.address?.mode === address?.mode
     this.address = address
     this.parentAvailable = parentAvailable
     if (!same && this.openState !== 'cold') void this.resync()

packages/client/runtime/tests/manager.spec.ts

@@ -286,38 +286,43 @@ describe('subagent catalogs', () => {
       summary(S2, { parentSessionId: S1, origin: 'subagent' }),
     ] as never[] }))
     api.onSubagentList = () => Promise.resolve(ok({
-      entries: [{ kind: 'child', id: S2, label: 'worker', activity: 'running' }] as never[],
+      entries: [{
+        kind: 'child', id: S2, mode: 'continuable', label: 'worker', activity: 'running',
+      }] as never[],
       parentAvailable: true,
     }))
     const manager = new SessionManager(api)
     await manager.refreshList()
     await manager.refreshSubagents(S1)
-    manager.selectSubagent({ parentSessionId: S1, childSessionId: S2 })
+    manager.selectSubagent({ parentSessionId: S1, childSessionId: S2, mode: 'continuable' })
 
     expect(manager.getListSnapshot().currentAddress).toEqual({
-      parentSessionId: S1, childSessionId: S2,
+      parentSessionId: S1, childSessionId: S2, mode: 'continuable',
     })
     expect(manager.get(S2).getSnapshot().subagent).toEqual({
-      address: { parentSessionId: S1, childSessionId: S2 },
+      address: { parentSessionId: S1, childSessionId: S2, mode: 'continuable' },
       parentAvailable: true,
     })
     // Clicking the same child through an ordinary list-selection path must not
     // erase the catalog-derived address and fall back to session.* transport.
     manager.select(S2)
     expect(manager.getListSnapshot().currentAddress).toEqual({
-      parentSessionId: S1, childSessionId: S2,
+      parentSessionId: S1, childSessionId: S2, mode: 'continuable',
     })
     expect(manager.get(S2).getSnapshot().subagent).toEqual({
-      address: { parentSessionId: S1, childSessionId: S2 },
+      address: { parentSessionId: S1, childSessionId: S2, mode: 'continuable' },
       parentAvailable: true,
     })
     await manager.get(S2).open()
     await manager.get(S2).prompt([{ type: 'text', text: 'continue' }], 'queue')
     expect(api.callsOf('subagent.history')).toEqual([
-      { parentSessionId: S1, childSessionId: S2, maxMessages: 50 },
+      { parentSessionId: S1, childSessionId: S2, mode: 'continuable', maxMessages: 50 },
     ])
     expect(api.callsOf('subagent.prompt')).toEqual([
-      { parentSessionId: S1, childSessionId: S2, content: [{ type: 'text', text: 'continue' }] },
+      {
+        parentSessionId: S1, childSessionId: S2, mode: 'continuable',
+        content: [{ type: 'text', text: 'continue' }],
+      },
     ])
     expect(api.callsOf('session.history')).toEqual([])
     expect(api.callsOf('session.prompt')).toEqual([])
@@ -337,7 +342,9 @@ describe('subagent catalogs', () => {
     })
     expect(manager.get(S2).getSnapshot()).toMatchObject({
       removed: false,
-      subagent: { address: { parentSessionId: S1, childSessionId: S2 } },
+      subagent: {
+        address: { parentSessionId: S1, childSessionId: S2, mode: 'continuable' },
+      },
     })
   })
 
@@ -554,7 +561,9 @@ describe('connected generation', () => {
 
   it('reloads the durable parent address for a restored child selection', async () => {
     const api = new FakeApiClient()
-    const address = { parentSessionId: S1, childSessionId: S2 }
+    const address = {
+      parentSessionId: S1, childSessionId: S2, mode: 'continuable' as const,
+    }
     const manager = new SessionManager(api, S2, address)
 
     manager.handleConnected()

packages/client/runtime/tests/session.spec.ts

@@ -584,7 +584,7 @@ describe('prompt and cancel errors', () => {
   it('routes an addressed child through non-activating history and continuation prompt only', async () => {
     const api = new FakeApiClient()
     const session = new Session(SID, api, {
-      address: { parentSessionId: PARENT, childSessionId: SID },
+      address: { parentSessionId: PARENT, childSessionId: SID, mode: 'continuable' },
       parentAvailable: true,
     })
     await session.open()
@@ -592,22 +592,40 @@ describe('prompt and cancel errors', () => {
     const cancelled = await session.cancel()
 
     expect(prompted).toEqual({ ok: true, value: { accepted: true } })
-    expect(cancelled).toMatchObject({ ok: false, error: { code: 'subagent-not-delivered' } })
+    expect(cancelled).toMatchObject({ ok: false, error: { code: 'subagent-delivery-unavailable' } })
     expect(api.callsOf('subagent.history')).toEqual([
-      { parentSessionId: PARENT, childSessionId: SID, maxMessages: 50 },
+      { parentSessionId: PARENT, childSessionId: SID, mode: 'continuable', maxMessages: 50 },
     ])
     expect(api.callsOf('subagent.prompt')).toEqual([
-      { parentSessionId: PARENT, childSessionId: SID, content: [{ type: 'text', text: '继续' }] },
+      {
+        parentSessionId: PARENT, childSessionId: SID, mode: 'continuable',
+        content: [{ type: 'text', text: '继续' }],
+      },
     ])
     expect(api.callsOf('session.history')).toEqual([])
     expect(api.callsOf('session.prompt')).toEqual([])
     expect(api.callsOf('session.cancel')).toEqual([])
     expect(session.getSnapshot().subagent).toEqual({
-      address: { parentSessionId: PARENT, childSessionId: SID },
+      address: { parentSessionId: PARENT, childSessionId: SID, mode: 'continuable' },
       parentAvailable: true,
     })
   })
 
+  it('keeps one-shot history readable without exposing prompt or cancel transport', async () => {
+    const api = new FakeApiClient()
+    const session = new Session(SID, api, {
+      address: { parentSessionId: PARENT, childSessionId: SID, mode: 'one-shot' },
+    })
+    await session.open()
+    const prompted = await session.prompt([{ type: 'text', text: '继续' }], 'queue')
+
+    expect(prompted).toMatchObject({ ok: false, error: { code: 'subagent-not-resumable' } })
+    expect(api.callsOf('subagent.history')).toEqual([
+      { parentSessionId: PARENT, childSessionId: SID, mode: 'one-shot', maxMessages: 50 },
+    ])
+    expect(api.callsOf('subagent.prompt')).toEqual([])
+  })
+
   it('sends content through session.prompt; composerPhase steps blank → engaging synchronously at send entry', async () => {
     const { api, session } = makeSession()
     // The blank → engaging edge fires before the RPC settles: the first-send