Update chat in editor titles after rename tool

src/vs/platform/agentHost/common/sessionDataService.ts

@@ -290,6 +290,12 @@ export interface ISessionDatabase extends IDisposable {
 	 */
 	setMetadataValues(values: Readonly<Record<string, string>>): Promise<void>;
 
+	/**
+	 * Atomically stores metadata values only when `key` is absent. Values named
+	 * by `copies` are read from their source keys and copied when present.
+	 */
+	setMetadataValuesIfAbsent(key: string, values: Readonly<Record<string, string>>, copies?: Readonly<Record<string, string>>): Promise<boolean>;
+
 	/**
 	 * Store or clear the draft for a chat in this session.
 	 */

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

@@ -1297,41 +1297,32 @@ 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

@@ -304,6 +304,7 @@ 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,
@@ -1719,13 +1720,16 @@ 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);
@@ -1926,6 +1930,34 @@ 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 (this._stateManager.getChatState(chat)?.title !== title) {
+				return;
+			}
+			const titleKey = customChatTitleMetadataKey(chat);
+			await ref.object.setMetadataValuesIfAbsent(
+				titleKey,
+				{ [titleKey]: title },
+				{ [customChatTitleSourceMetadataKey(chat)]: SESSION_CUSTOM_TITLE_SOURCE_KEY },
+			);
+		};
+		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/sessionDatabase.ts

@@ -700,6 +700,33 @@ export class SessionDatabase implements ISessionDatabase {
 		}));
 	}
 
+	setMetadataValuesIfAbsent(key: string, values: Readonly<Record<string, string>>, copies: Readonly<Record<string, string>> = {}): Promise<boolean> {
+		return this._track(() => this._metadataSequencer.queue(async () => {
+			const db = await this._ensureDb();
+			return this._transactionSequencer.queue(async () => {
+				await dbExec(db, 'BEGIN TRANSACTION');
+				try {
+					const existing = await dbGet(db, 'SELECT 1 FROM session_metadata WHERE key = ?', [key]);
+					if (existing) {
+						await dbExec(db, 'COMMIT');
+						return false;
+					}
+					for (const [targetKey, value] of Object.entries(values)) {
+						await dbRun(db, 'INSERT OR REPLACE INTO session_metadata (key, value) VALUES (?, ?)', [targetKey, value]);
+					}
+					for (const [targetKey, sourceKey] of Object.entries(copies)) {
+						await dbRun(db, 'INSERT OR REPLACE INTO session_metadata (key, value) SELECT ?, value FROM session_metadata WHERE key = ?', [targetKey, sourceKey]);
+					}
+					await dbExec(db, 'COMMIT');
+					return true;
+				} catch (err) {
+					await dbExec(db, 'ROLLBACK');
+					throw err;
+				}
+			});
+		}));
+	}
+
 	setChatDraft(chat: URI, draft: Message | undefined): Promise<void> {
 		const chatUri = chat.toString();
 		return this._track(async () => {

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/common/sessionTestHelpers.ts

@@ -89,6 +89,24 @@ export class TestSessionDatabase implements ISessionDatabase {
 		}
 	}
 
+	async setMetadataValuesIfAbsent(key: string, values: Readonly<Record<string, string>>, copies: Readonly<Record<string, string>> = {}): Promise<boolean> {
+		if (this._metadata.has(key)) {
+			return false;
+		}
+		for (const [targetKey, value] of Object.entries(values)) {
+			this.setMetadataCalls.push({ key: targetKey, value });
+			this._metadata.set(targetKey, value);
+		}
+		for (const [targetKey, sourceKey] of Object.entries(copies)) {
+			const value = this._metadata.get(sourceKey);
+			if (value !== undefined) {
+				this.setMetadataCalls.push({ key: targetKey, value });
+				this._metadata.set(targetKey, value);
+			}
+		}
+		return true;
+	}
+
 	async setChatDraft(chat: URI, draft: Message | undefined): Promise<void> {
 		const key = chat.toString();
 		if (draft) {

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' });