fix: preserve session title state invariants

packages/agent-core-v2/docs/state-manifest.d.ts

@@ -335,8 +335,7 @@ export interface SessionStateSnapshot {
     readonly id: string;
     readonly version?: number;
     readonly title?: string;
-    readonly titleSource?: 'prompt' | 'generated' | 'custom';
-    readonly isCustomTitle?: boolean;
+    readonly titleKind?: 'replaceable' | 'generated' | 'custom';
     readonly lastPrompt?: string;
     readonly createdAt: number;
     readonly updatedAt: number;
@@ -1009,7 +1008,7 @@ export interface AgentStateSnapshot {
   'llmRequester.lastConfigLogSignature': string | undefined;
   'llmRequester.mediaDegradedTurns': Set<number>;
   'llmRequester.mediaStrippedTurns': Map<number, /* MediaStripSnapshot — packages/agent-core-v2/src/agent/contextProjector/contextProjector.ts */ {
-    readonly "__@mediaStripSnapshotBrand@2657": undefined;
+    readonly "__@mediaStripSnapshotBrand@2658": undefined;
   }>;
   'llmRequester.turnConfigs': Map<number, /* TurnRequestConfig — packages/agent-core-v2/src/agent/llmRequester/llmRequesterService.ts */ {
     readonly resolved: /* ProfileModelContext — packages/agent-core-v2/src/agent/profile/profile.ts */ {

packages/agent-core-v2/src/agent/rpc/prompt-metadata.ts

@@ -8,7 +8,10 @@
  */
 
 import type { IEventService } from '#/app/event/event';
-import type { ISessionMetadata } from '#/session/sessionMetadata/sessionMetadata';
+import type {
+  ISessionMetadata,
+  SessionTitleKind,
+} from '#/session/sessionMetadata/sessionMetadata';
 
 import {
   promptMetadataTextFromContentParts,
@@ -61,12 +64,12 @@ export async function applyPromptMetadataUpdate(
 ): Promise<void> {
   if (text === undefined) return;
   const current = await target.metadata.read();
-  const patch: { lastPrompt: string; title?: string; isCustomTitle?: boolean } = {
+  const patch: { lastPrompt: string; title?: string; titleKind?: SessionTitleKind } = {
     lastPrompt: text,
   };
-  if (!current.isCustomTitle && isUntitled(current.title)) {
+  if (current.titleKind !== 'custom' && isUntitled(current.title)) {
     patch.title = titleFromPromptMetadataText(text);
-    patch.isCustomTitle = false;
+    patch.titleKind = 'replaceable';
   }
   await target.metadata.update(patch);
   target.eventService.publish({
@@ -77,7 +80,7 @@ export async function applyPromptMetadataUpdate(
       title: patch.title,
       patch: {
         title: patch.title,
-        isCustomTitle: patch.isCustomTitle,
+        isCustomTitle: patch.titleKind === undefined ? undefined : false,
         lastPrompt: text,
       },
     },

packages/agent-core-v2/src/app/sessionLifecycle/sessionLifecycleService.ts

@@ -428,7 +428,7 @@ export class SessionLifecycleService extends Disposable implements ISessionLifec
       const title = opts.title ?? `Fork: ${sourceMeta?.title || sourceId}`;
       await targetMeta.update({
         title,
-        isCustomTitle: opts.title !== undefined ? true : sourceMeta?.isCustomTitle === true,
+        titleKind: opts.title === undefined ? 'replaceable' : 'custom',
         forkedFrom: sourceId,
         archived: false,
         lastPrompt: sourceMeta?.lastPrompt,

packages/agent-core-v2/src/session/sessionMetadata/sessionMetadata.ts

@@ -25,12 +25,13 @@ export interface AgentMeta {
 
 export const SESSION_META_VERSION = 2;
 
+export type SessionTitleKind = 'replaceable' | 'generated' | 'custom';
+
 export interface SessionMeta {
   readonly id: string;
   readonly version?: number;
   readonly title?: string;
-  readonly titleSource?: 'prompt' | 'generated' | 'custom';
-  readonly isCustomTitle?: boolean;
+  readonly titleKind?: SessionTitleKind;
   readonly lastPrompt?: string;
   readonly createdAt: number;
   readonly updatedAt: number;

packages/agent-core-v2/src/session/sessionMetadata/sessionMetadataService.ts

@@ -44,6 +44,7 @@ import {
   type SessionMeta,
   type SessionMetadataChangedEvent,
   type SessionMetaPatch,
+  type SessionTitleKind,
 } from './sessionMetadata';
 
 const META_KEY = 'state.json';
@@ -109,14 +110,14 @@ export class SessionMetadata extends Disposable implements ISessionMetadata {
   }
 
   async setTitle(title: string): Promise<void> {
-    await this.update({ title, titleSource: 'custom', isCustomTitle: true });
+    await this.update({ title, titleKind: 'custom' });
   }
 
   async setGeneratedTitleIfUncustomized(title: string): Promise<boolean> {
     return this.enqueueUpdate(async () => {
       await this.ready;
-      if (this.data.isCustomTitle === true) return false;
-      await this.applyUpdate({ title, titleSource: 'generated', isCustomTitle: false });
+      if (this.data.titleKind === 'custom') return false;
+      await this.applyUpdate({ title, titleKind: 'generated' });
       return true;
     });
   }
@@ -174,7 +175,11 @@ export class SessionMetadata extends Disposable implements ISessionMetadata {
     const existing = await this.store.get<SessionMeta>(this.scope, META_KEY);
     if (existing !== undefined) {
       this.data = normalizeSessionMeta(existing, this.ctx.sessionId);
-      if (this.data.agents === undefined || this.data.custom === undefined) {
+      if (
+        this.data.agents === undefined ||
+        this.data.custom === undefined ||
+        sessionMetaTitleNeedsMigration(existing, this.data)
+      ) {
         this.data = {
           ...this.data,
           agents: this.data.agents ?? {},
@@ -220,45 +225,74 @@ function recordEquals(a: AgentMeta['labels'], b: AgentMeta['labels']): boolean {
 }
 
 export function normalizeSessionMeta(raw: SessionMeta, sessionId: string): SessionMeta {
-  const clean = { ...raw };
-  const legacy = raw as unknown as {
-    createdAt?: unknown;
-    updatedAt?: unknown;
-    workDir?: unknown;
-    customTitle?: unknown;
-  };
+  const legacy = raw as unknown as LegacySessionMeta;
+  const normalizedTitle = normalizeSessionTitle(legacy);
+  const {
+    createdAt: legacyCreatedAt,
+    updatedAt: legacyUpdatedAt,
+    workDir: legacyWorkDir,
+    titleSource: _legacyTitleSource,
+    isCustomTitle: _legacyIsCustomTitle,
+    customTitle: _legacyCustomTitle,
+    ...clean
+  } = legacy;
   const cwd =
-    clean.cwd ?? (typeof legacy.workDir === 'string' && legacy.workDir.length > 0
-      ? legacy.workDir
+    clean.cwd ?? (typeof legacyWorkDir === 'string' && legacyWorkDir.length > 0
+      ? legacyWorkDir
       : undefined);
-  const legacyCustomTitle =
-    typeof legacy.customTitle === 'string' ? legacy.customTitle : undefined;
-  const hasModernTitleState =
-    typeof clean.title === 'string' && typeof clean.isCustomTitle === 'boolean';
-  const title = hasModernTitleState ? clean.title : (legacyCustomTitle ?? clean.title);
-  const isCustomTitle = hasModernTitleState
-    ? clean.isCustomTitle
-    : legacyCustomTitle === undefined
-      ? clean.isCustomTitle
-      : true;
-  if (clean.version === SESSION_META_VERSION) {
-    if (cwd === clean.cwd && title === clean.title && isCustomTitle === clean.isCustomTitle) {
-      return clean;
-    }
-    return { ...clean, cwd, title, isCustomTitle };
-  }
+  const { title, titleKind } = normalizedTitle;
   return {
     ...clean,
-    id: sessionId,
+    id: clean.version === SESSION_META_VERSION ? clean.id : sessionId,
     version: SESSION_META_VERSION,
     cwd,
     title,
-    isCustomTitle,
-    createdAt: toEpochMs(legacy.createdAt),
-    updatedAt: toEpochMs(legacy.updatedAt),
+    titleKind,
+    createdAt: toEpochMs(legacyCreatedAt),
+    updatedAt: toEpochMs(legacyUpdatedAt),
   };
 }
 
+type LegacySessionMeta = Omit<SessionMeta, 'createdAt' | 'updatedAt'> & {
+  readonly createdAt?: unknown;
+  readonly updatedAt?: unknown;
+  readonly workDir?: unknown;
+  readonly titleSource?: unknown;
+  readonly isCustomTitle?: unknown;
+  readonly customTitle?: unknown;
+};
+
+function normalizeSessionTitle(
+  raw: LegacySessionMeta,
+): Pick<SessionMeta, 'title' | 'titleKind'> {
+  const title = typeof raw.title === 'string' ? raw.title : undefined;
+  if (title !== undefined && isSessionTitleKind(raw.titleKind)) {
+    return { title, titleKind: raw.titleKind };
+  }
+  if (title !== undefined && typeof raw.isCustomTitle === 'boolean') {
+    return { title, titleKind: raw.isCustomTitle ? 'custom' : 'replaceable' };
+  }
+  if (typeof raw.customTitle === 'string') {
+    return { title: raw.customTitle, titleKind: 'custom' };
+  }
+  return title === undefined ? {} : { title, titleKind: 'replaceable' };
+}
+
+function isSessionTitleKind(value: unknown): value is SessionTitleKind {
+  return value === 'replaceable' || value === 'generated' || value === 'custom';
+}
+
+function sessionMetaTitleNeedsMigration(raw: SessionMeta, normalized: SessionMeta): boolean {
+  const record = raw as unknown as Record<string, unknown>;
+  return (
+    raw.title !== normalized.title ||
+    raw.titleKind !== normalized.titleKind ||
+    Object.hasOwn(record, 'titleSource') ||
+    Object.hasOwn(record, 'isCustomTitle') ||
+    Object.hasOwn(record, 'customTitle')
+  );
+}
+
 export function toEpochMs(value: unknown): number {
   if (typeof value === 'number' && Number.isFinite(value)) return value;
   if (typeof value === 'string') {

packages/agent-core-v2/src/session/sessionTitle/sessionTitleService.ts

@@ -65,8 +65,8 @@ export class SessionTitleService implements ISessionTitleService {
 
   async generateTitle(options?: { readonly force?: boolean }): Promise<string | undefined> {
     const current = await this.metadata.read();
-    if (hasCustomTitle(current)) return undefined;
-    if (current.titleSource === 'generated' && options?.force !== true) return undefined;
+    if (current.titleKind === 'custom') return undefined;
+    if (current.titleKind === 'generated' && options?.force !== true) return undefined;
     const main = this.agentLifecycle.get(MAIN_AGENT_ID);
     const prompts =
       main === undefined
@@ -89,7 +89,7 @@ export class SessionTitleService implements ISessionTitleService {
 
   private async generateAndApplyOnce(chatContent: string): Promise<string | undefined> {
     const current = await this.metadata.read();
-    if (hasCustomTitle(current)) return undefined;
+    if (current.titleKind === 'custom') return undefined;
     const provider = this.providers.get(KIMI_CODE_PROVIDER_NAME);
     if (
       provider === undefined ||
@@ -158,17 +158,6 @@ export class SessionTitleService implements ISessionTitleService {
   }
 }
 
-function hasCustomTitle(metadata: {
-  readonly title?: unknown;
-  readonly isCustomTitle?: unknown;
-  readonly customTitle?: unknown;
-}): boolean {
-  if (typeof metadata.title === 'string' && typeof metadata.isCustomTitle === 'boolean') {
-    return metadata.isCustomTitle;
-  }
-  return metadata.isCustomTitle === true || typeof metadata.customTitle === 'string';
-}
-
 function titleInputFromPrompts(prompts: readonly string[]): string | undefined {
   if (prompts.length === 0) return undefined;
   return prompts

packages/agent-core-v2/test/agent/rpc/prompt-metadata.test.ts

@@ -97,6 +97,7 @@ describe('applyPromptMetadataUpdate', () => {
 
     expect(readMeta().lastPrompt).toBe('第二条');
     expect(readMeta().title).toBe('第一条');
+    expect(readMeta().titleKind).toBe('replaceable');
   });
 
   it('updates metadata for slash activations', async () => {

packages/agent-core-v2/test/app/sessionLifecycle/sessionLifecycle.test.ts

@@ -34,7 +34,10 @@ import { ISessionLifecycleService } from '#/app/sessionLifecycle/sessionLifecycl
 import { SessionLifecycleService } from '#/app/sessionLifecycle/sessionLifecycleService';
 import { IAgentActivityView } from '#/agent/activityView/activityView';
 import { ISessionExternalHooksService } from '#/session/externalHooks/externalHooks';
-import { ISessionMetadata } from '#/session/sessionMetadata/sessionMetadata';
+import {
+  ISessionMetadata,
+  type SessionMetaPatch,
+} from '#/session/sessionMetadata/sessionMetadata';
 import { ISessionSkillCatalog } from '#/session/sessionSkillCatalog/skillCatalog';
 import { ISessionToolPolicy } from '#/session/sessionToolPolicy/sessionToolPolicy';
 import { ISessionAgentProfileCatalog } from '#/session/sessionAgentProfileCatalog/sessionAgentProfileCatalog';
@@ -1181,6 +1184,55 @@ describe('SessionLifecycleService', () => {
       });
     }
 
+    it('marks the default fork title as replaceable', async () => {
+      const updates: SessionMetaPatch[] = [];
+      const svc = build([
+        workspaceGetStub(),
+        stubPair(ISessionMetadata, {
+          ...metadataStub(),
+          read: () =>
+            Promise.resolve({
+              title: 'generated source',
+              titleKind: 'generated',
+              agents: {},
+            } as never),
+          update: (patch) => {
+            updates.push(patch);
+            return Promise.resolve();
+          },
+        }),
+      ]);
+      await svc.create({ sessionId: 'src', workDir: '/tmp/proj' });
+
+      await svc.fork({ sourceSessionId: 'src', newSessionId: 'dst' });
+
+      expect(updates).toContainEqual(
+        expect.objectContaining({ title: 'Fork: generated source', titleKind: 'replaceable' }),
+      );
+    });
+
+    it('marks an explicit fork title as custom', async () => {
+      const updates: SessionMetaPatch[] = [];
+      const svc = build([
+        workspaceGetStub(),
+        stubPair(ISessionMetadata, {
+          ...metadataStub(),
+          read: () => Promise.resolve({ title: 'source', agents: {} } as never),
+          update: (patch) => {
+            updates.push(patch);
+            return Promise.resolve();
+          },
+        }),
+      ]);
+      await svc.create({ sessionId: 'src', workDir: '/tmp/proj' });
+
+      await svc.fork({ sourceSessionId: 'src', newSessionId: 'dst', title: 'user title' });
+
+      expect(updates).toContainEqual(
+        expect.objectContaining({ title: 'user title', titleKind: 'custom' }),
+      );
+    });
+
     it('copies blobs, plans, background tasks, and media originals into the fork', async () => {
       const root = await makeTmpRoot();
       const svc = build([

packages/agent-core-v2/test/session/sessionMetadata/sessionMetadata.test.ts

@@ -93,7 +93,7 @@ describe('SessionMetadata', () => {
     const meta = ix.get(ISessionMetadata);
     await meta.setTitle('t');
     await meta.setArchived(true);
-    expect(await meta.read()).toMatchObject({ title: 't', titleSource: 'custom', archived: true });
+    expect(await meta.read()).toMatchObject({ title: 't', titleKind: 'custom', archived: true });
   });
 
   it('sets a generated title while the metadata remains uncustomized', async () => {
@@ -102,8 +102,7 @@ describe('SessionMetadata', () => {
     await expect(meta.setGeneratedTitleIfUncustomized('generated title')).resolves.toBe(true);
     await expect(meta.read()).resolves.toMatchObject({
       title: 'generated title',
-      titleSource: 'generated',
-      isCustomTitle: false,
+      titleKind: 'generated',
     });
   });
 
@@ -183,13 +182,13 @@ describe('SessionMetadata', () => {
     const meta = ix.get(ISessionMetadata);
     await expect(meta.read()).resolves.toMatchObject({
       title: 'legacy title',
-      isCustomTitle: true,
+      titleKind: 'custom',
     });
 
     const fresh = createFreshMetadata(ix);
     await expect(fresh.read()).resolves.toMatchObject({
       title: 'legacy title',
-      isCustomTitle: true,
+      titleKind: 'custom',
     });
   });
 
@@ -209,16 +208,44 @@ describe('SessionMetadata', () => {
     const meta = ix.get(ISessionMetadata);
     await expect(meta.read()).resolves.toMatchObject({
       title: 'renamed title',
-      isCustomTitle: true,
+      titleKind: 'custom',
     });
 
     await meta.update({ archived: true });
     const fresh = createFreshMetadata(ix);
     await expect(fresh.read()).resolves.toMatchObject({
       title: 'renamed title',
-      isCustomTitle: true,
+      titleKind: 'custom',
       archived: true,
     });
+    const persisted = await store.get<Record<string, unknown>>(META_SCOPE, 'state.json');
+    expect(persisted).not.toHaveProperty('isCustomTitle');
+    expect(persisted).not.toHaveProperty('customTitle');
+  });
+
+  it('migrates a legacy non-custom title to replaceable title state', async () => {
+    const store = ix.get(IAtomicDocumentStore);
+    await store.set(META_SCOPE, 'state.json', {
+      id: 's1',
+      version: 2,
+      createdAt: 1700000000000,
+      updatedAt: 1700000000000,
+      archived: false,
+      title: 'prompt title',
+      isCustomTitle: false,
+      agents: {},
+      custom: {},
+    });
+
+    const meta = ix.get(ISessionMetadata);
+
+    await expect(meta.read()).resolves.toMatchObject({
+      title: 'prompt title',
+      titleKind: 'replaceable',
+    });
+    const persisted = await store.get<Record<string, unknown>>(META_SCOPE, 'state.json');
+    expect(persisted).toMatchObject({ title: 'prompt title', titleKind: 'replaceable' });
+    expect(persisted).not.toHaveProperty('isCustomTitle');
   });
 
   it('keeps a queued custom title when a generated title is enqueued afterward', async () => {
@@ -255,7 +282,7 @@ describe('SessionMetadata', () => {
     await expect(generated).resolves.toBe(false);
     await expect(meta.read()).resolves.toMatchObject({
       title: 'user title',
-      isCustomTitle: true,
+      titleKind: 'custom',
     });
   });
 

packages/agent-core-v2/test/session/sessionTitle/sessionTitleService.test.ts

@@ -1,6 +1,6 @@
 /**
  * Scenario: on-demand managed chat_title generation through the session-scoped
- * service, including OAuth failures, legacy custom titles, request headers,
+ * service, including OAuth failures, title-state transitions, request headers,
  * and races.
  * Wiring: the real title service with contract fakes; only fetch crosses the
  * external boundary. Run with `pnpm --filter @moonshot-ai/agent-core-v2 exec
@@ -100,12 +100,12 @@ class FakeSessionMetadata implements ISessionMetadata {
   }
 
   setTitle(title: string): Promise<void> {
-    return this.update({ title, titleSource: 'custom', isCustomTitle: true });
+    return this.update({ title, titleKind: 'custom' });
   }
 
   async setGeneratedTitleIfUncustomized(title: string): Promise<boolean> {
-    if (this.meta.isCustomTitle === true) return false;
-    await this.update({ title, titleSource: 'generated', isCustomTitle: false });
+    if (this.meta.titleKind === 'custom') return false;
+    await this.update({ title, titleKind: 'generated' });
     return true;
   }
 
@@ -252,8 +252,7 @@ describe('SessionTitleService', () => {
 
     expect(title).toBe('生成的标题');
     expect(metadata.meta.title).toBe('生成的标题');
-    expect(metadata.meta.isCustomTitle).toBe(false);
-    expect(metadata.meta.titleSource).toBe('generated');
+    expect(metadata.meta.titleKind).toBe('generated');
 
     const [, init] = fetchMock.mock.calls[0]!;
     expect(JSON.parse(init?.body as string)).toEqual({
@@ -329,7 +328,7 @@ describe('SessionTitleService', () => {
 
     await expect(generation).resolves.toBeUndefined();
     expect(metadata.meta.title).toBe('user 取的标题');
-    expect(metadata.meta.isCustomTitle).toBe(true);
+    expect(metadata.meta.titleKind).toBe('custom');
   });
 
   it('skips generation when the current title was already generated', async () => {
@@ -349,7 +348,7 @@ describe('SessionTitleService', () => {
       '生成的标题',
     );
     expect(metadata.meta.title).toBe('生成的标题');
-    expect(metadata.meta.titleSource).toBe('generated');
+    expect(metadata.meta.titleKind).toBe('generated');
   });
 
   it('never overwrites a custom title even when forced', async () => {
@@ -387,7 +386,7 @@ describe('SessionTitleService', () => {
   it('keeps the current title when the backend request fails', async () => {
     fetchMock.mockImplementationOnce(async () => new Response('', { status: 500 }));
     titlePrompts = ['hello'];
-    await metadata.update({ title: 'hello', isCustomTitle: false });
+    await metadata.update({ title: 'hello', titleKind: 'replaceable' });
 
     await expect(ix.get(ISessionTitleService).generateTitle()).resolves.toBeUndefined();
     expect(metadata.meta.title).toBe('hello');
@@ -479,29 +478,6 @@ describe('SessionTitleService', () => {
     expect(resolvedOAuthRefs[0]?.key).not.toBe(MANAGED_PROVIDER.oauth?.key);
   });
 
-  it('does not generate over a legacy customTitle', async () => {
-    metadata.meta = {
-      ...metadata.meta,
-      customTitle: 'legacy title',
-    } as SessionMeta;
-
-    await expect(ix.get(ISessionTitleService).generateTitle()).resolves.toBeUndefined();
-    expect(fetchMock).not.toHaveBeenCalled();
-  });
-
-  it('trusts a modern non-custom title over a stale legacy customTitle', async () => {
-    metadata.meta = {
-      ...metadata.meta,
-      title: 'easy title',
-      isCustomTitle: false,
-      customTitle: 'stale legacy title',
-    } as SessionMeta;
-    titlePrompts = ['hello'];
-
-    await expect(ix.get(ISessionTitleService).generateTitle()).resolves.toBe('生成的标题');
-    expect(metadata.meta.title).toBe('生成的标题');
-  });
-
   it('shares an in-flight generation between concurrent requests', async () => {
     const pendingFetch = createPendingFetch();
     fetchMock.mockImplementationOnce(pendingFetch.fetch);

packages/klient/src/contract/global/events.ts

@@ -30,7 +30,7 @@ export interface SessionMetaUpdatedPayload {
   readonly patch: {
     readonly title?: string;
     readonly isCustomTitle?: boolean;
-    readonly lastPrompt: string;
+    readonly lastPrompt?: string;
   };
 }
 
@@ -75,7 +75,7 @@ const sessionMetaUpdatedSchema = z.object({
     isCustomTitle: z.boolean().optional(),
     lastPrompt: z.string().optional(),
   }),
-});
+}) satisfies z.ZodType<SessionMetaUpdatedPayload>;
 
 export const catalogChangedSchema = z.object({
   changed: z.array(

packages/klient/src/contract/session/metadata.ts

@@ -22,8 +22,7 @@ export const sessionMetaSchema = z.object({
   id: z.string(),
   version: z.number().optional(),
   title: z.string().optional(),
-  titleSource: z.enum(['prompt', 'generated', 'custom']).optional(),
-  isCustomTitle: z.boolean().optional(),
+  titleKind: z.enum(['replaceable', 'generated', 'custom']).optional(),
   lastPrompt: z.string().optional(),
   createdAt: z.number(),
   updatedAt: z.number(),
@@ -38,8 +37,7 @@ export const sessionMetaSchema = z.object({
 export const sessionMetaPatchSchema = z.object({
   version: z.number().optional(),
   title: z.string().optional(),
-  titleSource: z.enum(['prompt', 'generated', 'custom']).optional(),
-  isCustomTitle: z.boolean().optional(),
+  titleKind: z.enum(['replaceable', 'generated', 'custom']).optional(),
   lastPrompt: z.string().optional(),
   updatedAt: z.number().optional(),
   archived: z.boolean().optional(),
@@ -54,8 +52,7 @@ export const sessionMetaKeySchema = z.enum([
   'id',
   'version',
   'title',
-  'titleSource',
-  'isCustomTitle',
+  'titleKind',
   'lastPrompt',
   'createdAt',
   'updatedAt',

packages/node-sdk/src/v2/session-mapper.ts

@@ -69,7 +69,7 @@ export function v2MetaToSessionMeta(meta: V2SessionMeta): SessionMeta {
     createdAt: new Date(meta.createdAt).toISOString(),
     updatedAt: new Date(meta.updatedAt).toISOString(),
     title: meta.title ?? '',
-    isCustomTitle: meta.isCustomTitle ?? false,
+    isCustomTitle: meta.titleKind === 'custom',
     lastPrompt: meta.lastPrompt,
     forkedFrom: meta.forkedFrom,
     workDir: meta.cwd,