fix(sessions): persist collaboration titles in local index

src/server/__tests__/local-index-session-parity.test.ts

@@ -40,6 +40,7 @@ class FakeLocalIndexGateway implements LocalIndexGateway {
   buildOnList = false
   listCalls = 0
   findCalls = 0
+  titleWrites: Array<{ sessionId: string; title: string }> = []
   lastListOptions: { project?: string; limit?: number; offset?: number } | undefined
 
   async start(): Promise<void> {}
@@ -67,6 +68,19 @@ class FakeLocalIndexGateway implements LocalIndexGateway {
   getSession(sessionId: string): IndexedSessionRow | null {
     return this.page.sessions.find(session => session.id === sessionId) ?? null
   }
+  updateSessionTitle(sessionId: string, title: string): boolean {
+    this.titleWrites.push({ sessionId, title })
+    let changed = false
+    this.page = {
+      ...this.page,
+      sessions: this.page.sessions.map(session => {
+        if (session.id !== sessionId) return session
+        changed = true
+        return { ...session, title }
+      }),
+    }
+    return changed
+  }
 
   setReady(mode: LocalIndexMode = 'on'): void {
     this.mode = mode
@@ -659,6 +673,42 @@ describe('SessionService local-index routing parity', () => {
     expect(gateway.listCalls).toBe(2)
   })
 
+  it('persists a collaboration metadata title into the index before a cold restart', async () => {
+    const projectDir = '-tmp-project'
+    const filePath = await writeSession(
+      projectDir,
+      SESSION_A,
+      'Initial child title',
+      '2026-07-15T00:00:00.000Z',
+    )
+    const gateway = new FakeLocalIndexGateway()
+    gateway.setReady()
+    gateway.page = {
+      sessions: [indexedRow(filePath, projectDir, SESSION_A, 'Initial child title')],
+      total: 1,
+    }
+    gateway.matches = [{ filePath, projectDir }]
+    const writer = new SessionService(gateway)
+
+    await writer.appendSessionMetadata(SESSION_A, {
+      workDir: configDir,
+      customTitle: '最终子会话标题',
+    })
+
+    expect(gateway.titleWrites).toContainEqual({
+      sessionId: SESSION_A,
+      title: '最终子会话标题',
+    })
+    const restartedGateway = new FakeLocalIndexGateway()
+    restartedGateway.setReady()
+    restartedGateway.page = {
+      sessions: gateway.page.sessions.map(session => ({ ...session })),
+      total: gateway.page.total,
+    }
+    const restarted = new SessionService(restartedGateway)
+    expect((await restarted.listSessions()).sessions[0]?.title).toBe('最终子会话标题')
+  })
+
   it('isolates shared mutation epochs between different gateways', async () => {
     const projectDir = '-tmp-project'
     const filePath = await writeSession(

src/server/services/localIndex/coordinator.ts

@@ -1523,6 +1523,16 @@ export function createLocalIndexCoordinator(
       }
     },
 
+    updateSessionTitle(sessionId: string, title: string): boolean {
+      if (!synchronizeRuntimeConfiguration() || !index?.updateSessionTitle) return false
+      try {
+        return index.updateSessionTitle(sessionId, title)
+      } catch (error) {
+        markDegraded(error, 'LOCAL_INDEX_TITLE_WRITE_FAILED')
+        return false
+      }
+    },
+
     getSessionEntryLocators(
       transcriptPath: string,
       entryTypes?: string[],

src/server/services/localIndex/sessionIndex.ts

@@ -80,6 +80,7 @@ export interface LocalIndexGateway extends SessionIndexReader {
   isActivityScopeReady?(): boolean
   getActivityStats?(range: StatsDateRange, now?: Date): ClaudeCodeStats | null
   rebuild(): Promise<LocalIndexStatus>
+  updateSessionTitle?(sessionId: string, title: string): boolean
   getSessionEntryLocators?(
     transcriptPath: string,
     entryTypes?: string[],
@@ -117,6 +118,7 @@ export interface SessionIndex extends SessionIndexReader, ActivityIndex {
   countSources(): number
   getProjectionSeed(path: string): TranscriptProjection | null
   getBackfillState(scope: string): PersistedBackfillState | null
+  updateSessionTitle?(sessionId: string, title: string): boolean
   getSessionEntryLocators(
     transcriptPath: string,
     entryTypes?: string[],
@@ -426,6 +428,14 @@ export function createSessionIndex(database: LocalIndexDatabase): SessionIndex {
       })
     },
 
+    updateSessionTitle(sessionId, title): boolean {
+      return database.write(operation => operation.run(
+        'UPDATE sessions SET title = ? WHERE session_id = ?',
+        title,
+        sessionId,
+      ).changes > 0)
+    },
+
     findSearchCandidates(filters): IndexedSessionSearchCandidate[] {
       const clauses: string[] = []
       const values: Array<string | number> = []

src/server/services/localIndex/sessionProjector.test.ts

@@ -88,6 +88,47 @@ async function sourceHash(path: string): Promise<string> {
 }
 
 describe('session projector', () => {
+  it('persists an immediate title patch without waiting for transcript reprojection', async () => {
+    const root = await createTempDir('projector-title-patch')
+    const databasePath = join(root, 'index.sqlite')
+    const placeholder = await createCandidate({
+      root,
+      projectPath: '-repo-placeholder',
+      sessionId: 'titled-child',
+      content: line(user('Initial child title', '2026-01-01T00:00:00Z')),
+    })
+    const moved = await createCandidate({
+      root,
+      projectPath: '-repo-worktree',
+      sessionId: 'titled-child',
+      content: line(user('Initial child title', '2026-01-01T00:00:01Z')),
+    })
+    const database = openLocalIndexDatabase({ path: databasePath })
+    const index = createSessionIndex(database)
+    try {
+      const projector = createSessionProjector({ database, index, scope: root })
+      expect((await projector.projectSource(placeholder)).kind).toBe('indexed')
+      expect((await projector.projectSource(moved)).kind).toBe('indexed')
+      await appendFile(moved.path, line({
+        type: 'custom-title',
+        customTitle: '最终子会话标题',
+      }))
+
+      expect(index.updateSessionTitle?.(moved.sessionId, '最终子会话标题')).toBe(true)
+    } finally {
+      database.close()
+    }
+
+    const restarted = openLocalIndexDatabase({ path: databasePath })
+    try {
+      const sessions = createSessionIndex(restarted).listSessions().sessions
+      expect(sessions).toHaveLength(2)
+      expect(sessions.every(session => session.title === '最终子会话标题')).toBe(true)
+    } finally {
+      restarted.close()
+    }
+  })
+
   it('rejects oversized records before concatenation and preserves the canonical file', async () => {
     const root = await createTempDir('projector-record-budget')
     const candidate = await createCandidate({ root, projectPath: '-repo', sessionId: 'large', content: line(user('x'.repeat(MAX_PROJECTION_RECORD_BYTES + 1), '2026-01-01T00:00:00Z')) })

src/server/services/sessionService.ts

@@ -820,6 +820,14 @@ export class SessionService {
     this.observedSharedMutationEpoch = sharedState.epoch
   }
 
+  private syncIndexedSessionTitle(sessionId: string, title: string): void {
+    // Title entries are tiny, authoritative mutations. Patch an existing index
+    // row immediately so a cold restart cannot briefly serve the older title
+    // while the transcript watcher is still queued. The watcher still performs
+    // the full source projection (fingerprint, locators, and metadata) later.
+    this.localIndexGateway.updateSessionTitle?.(sessionId, title)
+  }
+
   private prepareSessionListCaches(scope: string): void {
     if (this.activeSessionListCacheScope !== scope) {
       this.sessionListCache.clear()
@@ -4517,6 +4525,7 @@ export class SessionService {
     }
 
     await this.appendJsonlEntry(found.filePath, entry)
+    this.syncIndexedSessionTitle(sessionId, title)
     this.invalidateSessionListCache()
   }
 
@@ -4536,6 +4545,7 @@ export class SessionService {
       aiTitle: title,
       timestamp: new Date().toISOString(),
     })
+    this.syncIndexedSessionTitle(sessionId, title)
     this.invalidateSessionListCache()
   }
 
@@ -4713,6 +4723,9 @@ export class SessionService {
           .join('\n') + '\n',
         'utf-8',
       )
+      if (customTitleEntry) {
+        this.syncIndexedSessionTitle(sessionId, customTitleEntry.customTitle)
+      }
       this.invalidateSessionListCache()
     } catch (error) {
       // Clear aborts old-generation appends so none can land after a successful
@@ -4862,6 +4875,7 @@ export class SessionService {
         customTitle,
         timestamp: new Date().toISOString(),
       })
+      this.syncIndexedSessionTitle(sessionId, customTitle)
     }
     this.invalidateSessionListCache()
   }