Update chat in editor titles after rename tool

src/vs/platform/agentHost/node/agentHostStateManager.ts

@@ -280,6 +280,8 @@ export class AgentHostStateManager extends Disposable {
 
 	private readonly _onDidChangeSessionTitle = this._register(new Emitter<{ session: string; title: string }>());
 	readonly onDidChangeSessionTitle: Event<{ session: string; title: string }> = this._onDidChangeSessionTitle.event;
+	private readonly _onDidSnapshotDefaultChatTitle = this._register(new Emitter<{ session: string; chat: string; title: string }>());
+	readonly onDidSnapshotDefaultChatTitle: Event<{ session: string; chat: string; title: string }> = this._onDidSnapshotDefaultChatTitle.event;
 
 	private readonly _onDidChangeSessionConfig = this._register(new Emitter<{ session: URI; previous: SessionConfigState | undefined; current: SessionConfigState | undefined; clientContext?: IAgentHostClientTelemetryContext }>());
 	readonly onDidChangeSessionConfig: Event<{ session: URI; previous: SessionConfigState | undefined; current: SessionConfigState | undefined; clientContext?: IAgentHostClientTelemetryContext }> = this._onDidChangeSessionConfig.event;
@@ -1021,11 +1023,7 @@ export class AgentHostStateManager extends Disposable {
 		// titles become fully independent. Without this the default chat keeps
 		// an empty title (= inherit the session title), so renaming the session
 		// would also move the default chat tab and vice-versa.
-		const defaultChatUri = sessionState.defaultChat ?? buildDefaultChatUri(session);
-		const defaultEntry = sessionState.chats.find(c => c.resource === defaultChatUri);
-		if (defaultEntry && !defaultEntry.title && sessionState.title) {
-			this.updateChatTitle(session, defaultChatUri, sessionState.title);
-		}
+		this._snapshotDefaultChatTitle(session, sessionState);
 
 		const chatSummary: ChatSummary = {
 			...createDefaultChatSummary(this._toSummary(session, entry), chatUri),
@@ -1067,6 +1065,7 @@ export class AgentHostStateManager extends Disposable {
 			}
 			return existing;
 		}
+		this._snapshotDefaultChatTitle(session, sessionState);
 		const chatSummary: ChatSummary = {
 			...createDefaultChatSummary(this._toSummary(session, entry), chatUri),
 			title: options.title ?? '',
@@ -1077,7 +1076,7 @@ export class AgentHostStateManager extends Disposable {
 			...(options.origin ? { origin: options.origin } : {}),
 			interactivity: options.interactivity,
 		};
-		sessionState.chats = [...sessionState.chats, chatSummary];
+		entry.state.chats = [...entry.state.chats, chatSummary];
 		this._chatEntries.set(chatUri, {
 			session,
 			summary: chatSummary,
@@ -1089,6 +1088,15 @@ export class AgentHostStateManager extends Disposable {
 		return chatSummary;
 	}
 
+	private _snapshotDefaultChatTitle(session: URI, state: SessionState): void {
+		const defaultChat = buildDefaultChatUri(session);
+		const summary = state.chats.find(chat => chat.resource === defaultChat);
+		if (summary && !summary.title && state.title) {
+			this.updateChatTitle(session, defaultChat, state.title);
+			this._onDidSnapshotDefaultChatTitle.fire({ session, chat: defaultChat, title: state.title });
+		}
+	}
+
 	/**
 	 * Removes an additional chat from a session. Deletes its
 	 * {@link ChatState}, dispatches {@link ActionType.SessionChatRemoved}, and

src/vs/platform/agentHost/node/agentService.ts

@@ -1231,41 +1231,32 @@ export class AgentService extends Disposable implements IAgentService {
 	private async _renameChatFromTool(session: URI, chat: URI, title: string): Promise<IRenameTitleResult> {
 		validateRenameTitle(title, SessionServerToolName.RenameChat);
 		const isDefaultChat = isDefaultChatUri(chat.toString());
-		if (isDefaultChat && await this._isOnlySessionChat(session)) {
-			await persistSessionMetadataValues(this._sessionDataService, session.toString(), {
-				[SESSION_CUSTOM_TITLE_KEY]: title,
-				[SESSION_CUSTOM_TITLE_SOURCE_KEY]: AGENT_HOST_TITLE_SOURCE_AGENT,
-			});
-			if (this._stateManager.getSessionState(session.toString())?.title !== title) {
-				this._stateManager.dispatchServerAction(session.toString(), { type: ActionType.SessionTitleChanged, title });
-			}
-			this._sideEffects.markTitleRenamed(session.toString());
-			return { title };
-		}
 		if (!isDefaultChat && !await this._peerChatExists(session, chat)) {
 			throw new Error(`Invalid ${SessionServerToolName.RenameChat} input: chat must match a known non-default chat.`);
 		}
 
 		await persistSessionMetadataValues(this._sessionDataService, session.toString(), {
 			[customChatTitleMetadataKey(chat.toString())]: title,
 			[customChatTitleSourceMetadataKey(chat.toString())]: AGENT_HOST_TITLE_SOURCE_AGENT,
+			...(isDefaultChat ? {
+				[SESSION_CUSTOM_TITLE_KEY]: title,
+				[SESSION_CUSTOM_TITLE_SOURCE_KEY]: AGENT_HOST_TITLE_SOURCE_AGENT,
+			} : {}),
 		});
-		if (this._stateManager.getSessionState(session.toString())) {
+		const state = this._stateManager.getSessionState(session.toString());
+		if (state) {
+			if (isDefaultChat && state.title !== title) {
+				this._stateManager.dispatchServerAction(session.toString(), { type: ActionType.SessionTitleChanged, title });
+			}
 			this._stateManager.updateChatTitle(session.toString(), chat.toString(), title);
 		}
+		if (isDefaultChat) {
+			this._sideEffects.markTitleRenamed(session.toString());
+		}
 		this._sideEffects.markTitleRenamed(session.toString(), chat.toString());
 		return { title };
 	}
 
-	private async _isOnlySessionChat(session: URI): Promise<boolean> {
-		const state = this._stateManager.getSessionState(session.toString());
-		if (state) {
-			return state.chats.length === 1;
-		}
-		const persisted = await this._readPersistedPeerChatCatalog(session);
-		return persisted?.length === 0;
-	}
-
 	private async _peerChatExists(session: URI, chat: URI): Promise<boolean> {
 		if (this._stateManager.getSessionState(session.toString())?.chats.some(candidate => candidate.resource === chat.toString())) {
 			return true;

src/vs/platform/agentHost/node/agentSideEffects.ts

@@ -303,6 +303,7 @@ export class AgentSideEffects extends Disposable {
 			copilotApiService: this._options.copilotApiService,
 			isActiveAgentTitleGenerationEnabled: () => this._agentConfigService.getRootValue(platformRootSchema, AgentHostActiveAgentTitleGenerationConfigKey) === true,
 		}));
+		this._register(this._stateManager.onDidSnapshotDefaultChatTitle(event => this._persistDefaultChatTitleSnapshot(event.session, event.chat, event.title)));
 		this._localCommands = this._register(instantiationService.createInstance(
 			AgentHostLocalCommands,
 			this._stateManager,
@@ -1703,13 +1704,16 @@ export class AgentSideEffects extends Disposable {
 			}
 			case ActionType.SessionTitleChanged: {
 				if (chatChannel) {
-					// The rename targeted a specific chat (default or additional),
-					// not the whole session. Route it to a per-chat title update so
-					// the session title stays independent.
 					this._stateManager.updateChatTitle(sessionChannel, chatChannel, action.title);
 					this._persistSessionFlag(sessionChannel, customChatTitleMetadataKey(chatChannel), action.title);
 					this._persistSessionFlag(sessionChannel, customChatTitleSourceMetadataKey(chatChannel), AGENT_HOST_TITLE_SOURCE_USER);
 					this._titleController.markTitleRenamed(sessionChannel, chatChannel);
+					if (isDefaultChatUri(chatChannel)) {
+						this._stateManager.dispatchServerAction(sessionChannel, action);
+						this._persistSessionFlag(sessionChannel, SESSION_CUSTOM_TITLE_KEY, action.title);
+						this._persistSessionFlag(sessionChannel, SESSION_CUSTOM_TITLE_SOURCE_KEY, AGENT_HOST_TITLE_SOURCE_USER);
+						this._titleController.markTitleRenamed(sessionChannel);
+					}
 					break;
 				}
 				this._persistSessionFlag(channel, SESSION_CUSTOM_TITLE_KEY, action.title);
@@ -1910,6 +1914,32 @@ export class AgentSideEffects extends Disposable {
 		persistSessionMetadata(this._options.sessionDataService, this._logService, session, key, value);
 	}
 
+	private _persistDefaultChatTitleSnapshot(session: ProtocolURI, chat: ProtocolURI, title: string): void {
+		const ref = (() => {
+			try {
+				return this._options.sessionDataService.openDatabase(URI.parse(session));
+			} catch (error) {
+				this._logService.warn('[AgentSideEffects] Failed to open session database for default chat title snapshot', error);
+				return undefined;
+			}
+		})();
+		if (!ref) {
+			return;
+		}
+		const persist = async () => {
+			if (await ref.object.getMetadata(customChatTitleMetadataKey(chat)) !== undefined) {
+				return;
+			}
+			if (this._stateManager.getChatState(chat)?.title !== title) {
+				return;
+			}
+			await ref.object.setMetadata(customChatTitleMetadataKey(chat), title);
+		};
+		void persist().catch(error => {
+			this._logService.warn('[AgentSideEffects] Failed to persist default chat title snapshot', error);
+		}).finally(() => ref.dispose());
+	}
+
 	/**
 	 * Persists the usage reported for a chat's turn.
 	 *

src/vs/platform/agentHost/node/localCommands/renameLocalCommand.ts

@@ -40,15 +40,19 @@ export class RenameLocalCommand extends Disposable implements ILocalChatCommand
 			// completes the turn.
 			return;
 		}
-		const isAdditional = (uri: ProtocolURI): boolean => isAhpChatChannel(uri) && !isDefaultChatUri(uri);
-		const chatTarget = isAdditional(channel) ? channel : undefined;
+		const chatTarget = isAhpChatChannel(channel) ? channel : undefined;
 		const sessionChannel = isAhpChatChannel(channel) ? parseRequiredSessionUriFromChatUri(channel) : channel;
 		if (chatTarget) {
-			// Rename only this chat, independently of the session title.
 			this._context.updateChatTitle(sessionChannel, chatTarget, title);
 			this._context.markTitleRenamed(sessionChannel, chatTarget);
 			this._context.persistSessionFlag(sessionChannel, customChatTitleMetadataKey(chatTarget), title);
 			this._context.persistSessionFlag(sessionChannel, customChatTitleSourceMetadataKey(chatTarget), AGENT_HOST_TITLE_SOURCE_USER);
+			if (isDefaultChatUri(chatTarget)) {
+				this._context.dispatch(sessionChannel, { type: ActionType.SessionTitleChanged, title });
+				this._context.markTitleRenamed(sessionChannel);
+				this._context.persistSessionFlag(sessionChannel, SESSION_CUSTOM_TITLE_KEY, title);
+				this._context.persistSessionFlag(sessionChannel, SESSION_CUSTOM_TITLE_SOURCE_KEY, AGENT_HOST_TITLE_SOURCE_USER);
+			}
 		} else {
 			this._context.dispatch(sessionChannel, { type: ActionType.SessionTitleChanged, title });
 			this._context.markTitleRenamed(sessionChannel);

src/vs/platform/agentHost/node/shared/sessionServerTools.ts

@@ -168,7 +168,7 @@ export const sessionServerToolDefinitions: ToolDefinition[] = [
 	{
 		name: SessionServerToolName.RenameChat,
 		title: 'Rename Chat',
-		description: 'Rename one specific chat so it is easy to find later. When a session has only its default chat, renaming that chat also names the session. Once the session has multiple chats, only the targeted chat is renamed. Use a short, human-friendly chat name in sentence case (1-4 words). Pass an `agent-host-session://` session or chat link to target another chat, or omit `chat` to rename the chat in which this tool is running. Name a fresh chat once its scope is clear, typically soon after `create_chat` or early in that chat. Call this tool again whenever the user explicitly asks to rename the chat; every invocation replaces the current title.',
+		description: 'Rename one specific chat so it is easy to find later. Renaming the default chat also names its owning session, while peer-chat titles remain independent. Use a short, human-friendly chat name in sentence case (1-4 words). Pass an `agent-host-session://` session or chat link to target another chat, or omit `chat` to rename the chat in which this tool is running. Name a fresh chat once its scope is clear, typically soon after `create_chat` or early in that chat. Call this tool again whenever the user explicitly asks to rename the chat; every invocation replaces the current title.',
 		inputSchema: renameChatInputSchema,
 		annotations: { readOnlyHint: false },
 	},

src/vs/platform/agentHost/test/node/agentHostStateManager.test.ts

@@ -1136,6 +1136,43 @@ suite('AgentHostStateManager', () => {
 			);
 		});
 
+		test('restored peer chat snapshots the inherited default chat title', () => {
+			manager.restoreSession(makeSessionSummary(), []);
+			const defaultChat = buildDefaultChatUri(sessionUri);
+			const beforeRestore = manager.getSessionState(sessionUri)?.chats.find(chat => chat.resource === defaultChat)?.title;
+
+			manager.registerRestoredChatSummary(sessionUri, peerChat, { title: 'Peer' });
+
+			assert.deepStrictEqual({
+				beforeRestore,
+				afterRestore: manager.getSessionState(sessionUri)?.chats.find(chat => chat.resource === defaultChat)?.title,
+			}, {
+				beforeRestore: '',
+				afterRestore: 'Test',
+			});
+		});
+
+		test('adding a chat snapshots the canonical default when routing defaults to a peer', () => {
+			manager.createSession(makeSessionSummary());
+			const canonicalDefault = buildDefaultChatUri(sessionUri);
+			const peer2 = buildChatUri(sessionUri, 'peer-2');
+			manager.addChat(sessionUri, peerChat, { title: 'Peer' });
+			manager.updateChatTitle(sessionUri, canonicalDefault, '');
+			manager.updateChatTitle(sessionUri, peerChat, '');
+			manager.dispatchServerAction(sessionUri, { type: ActionType.SessionDefaultChatChanged, defaultChat: peerChat });
+
+			manager.addChat(sessionUri, peer2, { title: 'Peer 2' });
+
+			const state = manager.getSessionState(sessionUri);
+			assert.deepStrictEqual({
+				canonicalDefaultTitle: state?.chats.find(chat => chat.resource === canonicalDefault)?.title,
+				routingDefaultTitle: state?.chats.find(chat => chat.resource === peerChat)?.title,
+			}, {
+				canonicalDefaultTitle: 'Test',
+				routingDefaultTitle: '',
+			});
+		});
+
 		test('addChat is idempotent for an existing chat URI', () => {
 			manager.createSession(makeSessionSummary());
 			const first = manager.addChat(sessionUri, peerChat, { title: 'Peer' });

src/vs/platform/agentHost/test/node/agentService.test.ts

@@ -9345,6 +9345,16 @@ suite('AgentService (node dispatcher)', () => {
 			return [];
 		}
 
+		async function waitForMetadata(db: TestSessionDatabase, key: string, expected: string): Promise<void> {
+			for (let i = 0; i < 50; i++) {
+				if (await db.getMetadata(key) === expected) {
+					return;
+				}
+				await timeout(0);
+			}
+			assert.fail(`Metadata '${key}' did not become '${expected}'`);
+		}
+
 		test('rolls back a new peer chat when its catalog entry cannot be persisted', async () => {
 			class FailingPeerCatalogDatabase extends TestSessionDatabase {
 				failPeerCatalogWrites = false;
@@ -9427,6 +9437,39 @@ suite('AgentService (node dispatcher)', () => {
 			assert.ok(!registered.includes(AgentSession.uri('copilot', 'restored-peer-backing-sdk-id').toString()), 'the backing session must not leak into the registered session list');
 		});
 
+		test('restores the snapshotted default chat title after the session is renamed', async () => {
+			class MultiChatAgent extends MockAgent {
+				override async createChat(): Promise<void> { }
+			}
+			const db = new TestSessionDatabase();
+			const localService = disposables.add(new AgentService(new NullLogService(), fileService, createSessionDataService(db), { _serviceBrand: undefined } as IProductService, createNoopGitService()));
+			const agent = disposables.add(new MultiChatAgent('copilot'));
+			localService.registerProvider(agent);
+			const session = await localService.createSession({ provider: 'copilot' });
+			const sessionUri = session.toString();
+			const defaultChat = buildDefaultChatUri(session);
+			const peerChat = URI.parse(buildChatUri(session, 'peer'));
+			localService.dispatchAction(sessionUri, { type: ActionType.SessionTitleChanged, title: 'Default A' }, 'test-client', 1);
+			await waitForMetadata(db, 'customTitle', 'Default A');
+
+			await localService.createChat(session, peerChat);
+			await waitForMetadata(db, `customChatTitle:${defaultChat}`, 'Default A');
+			localService.dispatchAction(sessionUri, { type: ActionType.SessionTitleChanged, title: 'Session B' }, 'test-client', 2);
+			await waitForMetadata(db, 'customTitle', 'Session B');
+
+			localService.stateManager.deleteSession(sessionUri);
+			await localService.restoreSession(session);
+
+			const restored = localService.stateManager.getSessionState(sessionUri);
+			assert.deepStrictEqual({
+				sessionTitle: restored?.title,
+				defaultChatTitle: restored?.chats.find(chat => chat.resource === defaultChat)?.title,
+			}, {
+				sessionTitle: 'Session B',
+				defaultChatTitle: 'Default A',
+			});
+		});
+
 		test('restore registers peer-chat metadata in catalog order and loads history on first access', async () => {
 			const calls: { call: string; uri: string; providerData?: string }[] = [];
 			class MultiChatAgent extends MockAgent {
@@ -10538,6 +10581,14 @@ suite('AgentService (node dispatcher)', () => {
 			await db.setMetadata('customTitleSource', 'user');
 			await db.setMetadata(`customChatTitle:${peerChat}`, 'Previous peer title');
 			await db.setMetadata(`customChatTitleSource:${peerChat}`, 'user');
+			await timeout(0);
+			localService.stateManager.prepareSessionSummariesForListing([localService.stateManager.getSessionSummary(sessionUri)!]);
+			const summaryTitleChanged = new DeferredPromise<string>();
+			disposables.add(localService.onDidNotification(notification => {
+				if (notification.type === NotificationType.SessionSummaryChanged && notification.changes.title) {
+					void summaryTitleChanged.complete(notification.changes.title);
+				}
+			}));
 
 			const multiChatDefaultResult = await agent.serverToolHost!.executeTool(defaultChat, SessionServerToolName.RenameChat, {
 				title: 'Complete replacement default chat title',
@@ -10547,7 +10598,7 @@ suite('AgentService (node dispatcher)', () => {
 				title: 'Complete replacement peer chat title',
 			});
 			await db.finalRenamePersisted.p;
-			await timeout(0);
+			const summaryTitleChange = await summaryTitleChanged.p;
 
 			assert.deepStrictEqual({
 				singleChatResult,
@@ -10562,19 +10613,21 @@ suite('AgentService (node dispatcher)', () => {
 				persistedDefaultChatSource: await db.getMetadata(`customChatTitleSource:${defaultChat}`),
 				persistedChatTitle: await db.getMetadata(`customChatTitle:${peerChat}`),
 				persistedChatSource: await db.getMetadata(`customChatTitleSource:${peerChat}`),
+				summaryTitleChange,
 			}, {
 				singleChatResult: 'Renamed chat to "Single-chat title".',
 				multiChatDefaultResult: 'Renamed chat to "Complete replacement default chat title".',
 				chatResult: 'Renamed chat to "Complete replacement peer chat title".',
-				liveSessionTitle: 'Multi-chat session title',
+				liveSessionTitle: 'Complete replacement default chat title',
 				liveDefaultChatTitle: 'Complete replacement default chat title',
 				liveChatTitle: 'Complete replacement peer chat title',
-				persistedSessionTitle: 'Multi-chat session title',
-				persistedSessionSource: 'user',
+				persistedSessionTitle: 'Complete replacement default chat title',
+				persistedSessionSource: 'agent',
 				persistedDefaultChatTitle: 'Complete replacement default chat title',
 				persistedDefaultChatSource: 'agent',
 				persistedChatTitle: 'Complete replacement peer chat title',
 				persistedChatSource: 'agent',
+				summaryTitleChange: 'Complete replacement default chat title',
 			});
 		});