sessions: set session title to first message text immediately

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

@@ -178,11 +178,19 @@ export class AgentService extends Disposable implements IAgentService {
 			return s;
 		}));
 
-		// Overlay live session status from the state manager
+		// Overlay live session state from the state manager.
+		// For the title, prefer the state manager's value when it is
+		// non-empty, so SDK-sourced titles are not overwritten by the
+		// initial empty placeholder.
 		const withStatus = result.map(s => {
 			const liveState = this._stateManager.getSessionState(s.session.toString());
 			if (liveState) {
-				return { ...s, status: liveState.summary.status, model: liveState.summary.model ?? s.model };
+				return {
+					...s,
+					summary: liveState.summary.title || s.summary,
+					status: liveState.summary.status,
+					model: liveState.summary.model ?? s.model,
+				};
 			}
 			return s;
 		});
@@ -262,7 +270,7 @@ export class AgentService extends Disposable implements IAgentService {
 			const summary: ISessionSummary = {
 				resource: session.toString(),
 				provider: provider.id,
-				title: 'New Session',
+				title: '',
 				status: SessionStatus.Idle,
 				createdAt: Date.now(),
 				modifiedAt: Date.now(),

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

@@ -568,6 +568,22 @@ export class AgentSideEffects extends Disposable {
 				for (const mapper of this._eventMappers.values()) {
 					mapper.reset(action.session);
 				}
+
+				// On the very first turn, immediately set the session title to the
+				// user's message so the UI shows a meaningful title right away
+				// while waiting for the AI-generated title. Only apply when the
+				// title is still the default placeholder to avoid clobbering a
+				// title set by the user or provider before the first turn.
+				const state = this._stateManager.getSessionState(action.session);
+				const fallbackTitle = action.userMessage.text.trim().replace(/\s+/g, ' ').slice(0, 200);
+				if (state && state.turns.length === 0 && !state.summary.title && fallbackTitle.length > 0) {
+					this._stateManager.dispatchServerAction({
+						type: ActionType.SessionTitleChanged,
+						session: action.session,
+						title: fallbackTitle,
+					});
+				}
+
 				const agent = this._options.getAgent(action.session);
 				if (!agent) {
 					this._stateManager.dispatchServerAction({

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

@@ -222,6 +222,23 @@ suite('AgentService (node dispatcher)', () => {
 			assert.strictEqual(sessions[0].summary, 'Auto-generated Title');
 		});
 
+		test('listSessions overlays live state manager title over SDK title', async () => {
+			service.registerProvider(copilotAgent);
+
+			const session = await service.createSession({ provider: 'copilot' });
+
+			// Simulate immediate title change via state manager
+			service.stateManager.dispatchServerAction({
+				type: ActionType.SessionTitleChanged,
+				session: session.toString(),
+				title: 'User first message',
+			});
+
+			const sessions = await service.listSessions();
+			assert.strictEqual(sessions.length, 1);
+			assert.strictEqual(sessions[0].summary, 'User first message');
+		});
+
 		test('createSession stores live session config', async () => {
 			service.registerProvider(copilotAgent);
 

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

@@ -130,7 +130,136 @@ suite('AgentSideEffects', () => {
 		});
 	});
 
-	// ---- handleAction: session/turnCancelled ----------------------------
+	// ---- immediate title on first turn -----------------------------------
+
+	suite('immediate title on first turn', () => {
+
+		function setupDefaultSession(): void {
+			stateManager.createSession({
+				resource: sessionUri.toString(),
+				provider: 'mock',
+				title: '',
+				status: SessionStatus.Idle,
+				createdAt: Date.now(),
+				modifiedAt: Date.now(),
+				project: { uri: 'file:///test-project', displayName: 'Test Project' },
+			});
+			stateManager.dispatchServerAction({ type: ActionType.SessionReady, session: sessionUri.toString() });
+		}
+
+		test('dispatches titleChanged with user message on first turn', () => {
+			setupDefaultSession();
+
+			const envelopes: IActionEnvelope[] = [];
+			disposables.add(stateManager.onDidEmitEnvelope(e => envelopes.push(e)));
+
+			sideEffects.handleAction({
+				type: ActionType.SessionTurnStarted,
+				session: sessionUri.toString(),
+				turnId: 'turn-1',
+				userMessage: { text: 'Fix the login bug' },
+			});
+
+			const titleAction = envelopes.find(e => e.action.type === ActionType.SessionTitleChanged);
+			assert.ok(titleAction, 'should dispatch session/titleChanged');
+			if (titleAction?.action.type === ActionType.SessionTitleChanged) {
+				assert.strictEqual(titleAction.action.title, 'Fix the login bug');
+			}
+		});
+
+		test('does not dispatch titleChanged when message is whitespace', () => {
+			setupDefaultSession();
+
+			const envelopes: IActionEnvelope[] = [];
+			disposables.add(stateManager.onDidEmitEnvelope(e => envelopes.push(e)));
+
+			sideEffects.handleAction({
+				type: ActionType.SessionTurnStarted,
+				session: sessionUri.toString(),
+				turnId: 'turn-1',
+				userMessage: { text: '   ' },
+			});
+
+			const titleAction = envelopes.find(e => e.action.type === ActionType.SessionTitleChanged);
+			assert.strictEqual(titleAction, undefined, 'should not dispatch titleChanged for empty message');
+		});
+
+		test('normalizes whitespace and truncates long messages', () => {
+			setupDefaultSession();
+
+			const envelopes: IActionEnvelope[] = [];
+			disposables.add(stateManager.onDidEmitEnvelope(e => envelopes.push(e)));
+
+			const longMessage = 'Fix the bug\nin the login\tpage  please ' + 'a'.repeat(250);
+			sideEffects.handleAction({
+				type: ActionType.SessionTurnStarted,
+				session: sessionUri.toString(),
+				turnId: 'turn-1',
+				userMessage: { text: longMessage },
+			});
+
+			const titleAction = envelopes.find(e => e.action.type === ActionType.SessionTitleChanged);
+			assert.ok(titleAction, 'should dispatch session/titleChanged');
+			if (titleAction?.action.type === ActionType.SessionTitleChanged) {
+				assert.ok(!titleAction.action.title.includes('\n'), 'should not contain newlines');
+				assert.ok(!titleAction.action.title.includes('\t'), 'should not contain tabs');
+				assert.ok(!titleAction.action.title.includes('  '), 'should not contain double spaces');
+				assert.ok(titleAction.action.title.length <= 200, 'should be truncated to 200 chars');
+			}
+		});
+
+		test('does not dispatch titleChanged on second turn', () => {
+			setupDefaultSession();
+			startTurn('turn-1');
+
+			// Complete the first turn so turns.length becomes 1.
+			stateManager.dispatchServerAction({
+				type: ActionType.SessionTurnComplete,
+				session: sessionUri.toString(),
+				turnId: 'turn-1',
+			});
+
+			const envelopes: IActionEnvelope[] = [];
+			disposables.add(stateManager.onDidEmitEnvelope(e => envelopes.push(e)));
+
+			sideEffects.handleAction({
+				type: ActionType.SessionTurnStarted,
+				session: sessionUri.toString(),
+				turnId: 'turn-2',
+				userMessage: { text: 'second message' },
+			});
+
+			const titleAction = envelopes.find(e => e.action.type === ActionType.SessionTitleChanged);
+			assert.strictEqual(titleAction, undefined, 'should not dispatch titleChanged on second turn');
+		});
+
+		test('does not dispatch titleChanged when title is already set', () => {
+			// Session has a non-empty title (e.g. user renamed before first message)
+			stateManager.createSession({
+				resource: sessionUri.toString(),
+				provider: 'mock',
+				title: 'User Renamed',
+				status: SessionStatus.Idle,
+				createdAt: Date.now(),
+				modifiedAt: Date.now(),
+				project: { uri: 'file:///test-project', displayName: 'Test Project' },
+			});
+			stateManager.dispatchServerAction({ type: ActionType.SessionReady, session: sessionUri.toString() });
+
+			const envelopes: IActionEnvelope[] = [];
+			disposables.add(stateManager.onDidEmitEnvelope(e => envelopes.push(e)));
+
+			sideEffects.handleAction({
+				type: ActionType.SessionTurnStarted,
+				session: sessionUri.toString(),
+				turnId: 'turn-1',
+				userMessage: { text: 'hello' },
+			});
+
+			const titleAction = envelopes.find(e => e.action.type === ActionType.SessionTitleChanged);
+			assert.strictEqual(titleAction, undefined, 'should not clobber existing title');
+		});
+	});
 
 	suite('handleAction — session/turnCancelled', () => {
 

src/vs/platform/agentHost/test/node/protocol/sessionFeatures.integrationTest.ts

@@ -77,7 +77,15 @@ suite('Protocol WebSocket — Session Features', function () {
 		const sessionUri = await createAndSubscribeSession(client, 'test-agent-title');
 		dispatchTurnStarted(client, sessionUri, 'turn-title', 'with-title', 1);
 
-		const titleNotif = await client.waitForNotification(n => isActionNotification(n, 'session/titleChanged'));
+		// The first titleChanged is the immediate fallback (user message text).
+		// Wait for the agent-generated title which arrives second.
+		const titleNotif = await client.waitForNotification(n => {
+			if (!isActionNotification(n, 'session/titleChanged')) {
+				return false;
+			}
+			const action = getActionEnvelope(n).action as ITitleChangedAction;
+			return action.title === MOCK_AUTO_TITLE;
+		});
 		const titleAction = getActionEnvelope(titleNotif).action as ITitleChangedAction;
 		assert.strictEqual(titleAction.title, MOCK_AUTO_TITLE);
 
@@ -88,6 +96,31 @@ suite('Protocol WebSocket — Session Features', function () {
 		assert.strictEqual(state.summary.title, MOCK_AUTO_TITLE);
 	});
 
+	test('first turn immediately sets title to user message', async function () {
+		this.timeout(10_000);
+
+		const sessionUri = await createAndSubscribeSession(client, 'test-immediate-title');
+
+		// Verify the session starts with the default placeholder title
+		const before = await client.call<ISubscribeResult>('subscribe', { resource: sessionUri });
+		assert.strictEqual((before.snapshot.state as ISessionState).summary.title, '');
+
+		// Send first turn — side effects should dispatch an immediate titleChanged
+		// with the user's message text before the agent produces its own title.
+		dispatchTurnStarted(client, sessionUri, 'turn-immediate', 'Fix the login bug', 1);
+
+		// The first titleChanged should carry the user message text
+		const titleNotif = await client.waitForNotification(n => isActionNotification(n, 'session/titleChanged'));
+		const titleAction = getActionEnvelope(titleNotif).action as ITitleChangedAction;
+		assert.strictEqual(titleAction.title, 'Fix the login bug');
+
+		// listSessions should also reflect the updated title
+		const result = await client.call<IListSessionsResult>('listSessions');
+		const session = result.items.find(s => s.resource === sessionUri);
+		assert.ok(session, 'session should appear in listSessions');
+		assert.strictEqual(session.title, 'Fix the login bug');
+	});
+
 	test('renamed session title persists across listSessions', async function () {
 		this.timeout(10_000);
 

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

@@ -9,7 +9,7 @@ import { DisposableStore } from '../../../../base/common/lifecycle.js';
 import { URI } from '../../../../base/common/uri.js';
 import { ensureNoDisposablesAreLeakedInTestSuite } from '../../../../base/test/common/utils.js';
 import { NullLogService } from '../../../log/common/log.js';
-import type { IAgentCreateSessionConfig, IAgentResolveSessionConfigParams, IAgentService, IAgentSessionConfigCompletionsParams, IAgentSessionMetadata, IAuthenticateParams, IAuthenticateResult } from '../../common/agentService.js';
+import { type IAgentCreateSessionConfig, type IAgentResolveSessionConfigParams, type IAgentService, type IAgentSessionConfigCompletionsParams, type IAgentSessionMetadata, type IAuthenticateParams, type IAuthenticateResult } from '../../common/agentService.js';
 import { IListSessionsResult, IResourceReadResult, IResolveSessionConfigResult, ISessionConfigCompletionsResult } from '../../common/state/protocol/commands.js';
 import { ActionType, type ISessionAction } from '../../common/state/sessionActions.js';
 import { PROTOCOL_VERSION } from '../../common/state/sessionCapabilities.js';
@@ -95,7 +95,7 @@ class MockAgentService implements IAgentService {
 		this._stateManager.createSession({
 			resource: session.toString(),
 			provider: config?.provider ?? 'copilot',
-			title: 'New Session',
+			title: '',
 			status: SessionStatus.Idle,
 			createdAt: Date.now(),
 			modifiedAt: Date.now(),

src/vs/sessions/contrib/localAgentHost/browser/localAgentHostSessionsProvider.ts

@@ -112,7 +112,7 @@ class LocalSessionAdapter implements ISession {
 		this.providerId = providerId;
 		this.sessionType = logicalSessionType;
 		this.createdAt = new Date(metadata.startTime);
-		this.title = observableValue('title', metadata.summary ?? `Session ${rawId.substring(0, 8)}`);
+		this.title = observableValue('title', metadata.summary || `Session ${rawId.substring(0, 8)}`);
 		this.updatedAt = observableValue('updatedAt', new Date(metadata.modifiedTime));
 		this.modelId = observableValue<string | undefined>('modelId', metadata.model ? `${logicalSessionType}:${metadata.model}` : undefined);
 		this.lastTurnEnd = observableValue('lastTurnEnd', metadata.modifiedTime ? new Date(metadata.modifiedTime) : undefined);

src/vs/sessions/contrib/remoteAgentHost/browser/remoteAgentHostSessionsProvider.ts

@@ -195,7 +195,7 @@ class RemoteSessionAdapter implements IChatData {
 		this.providerId = providerId;
 		this.sessionType = logicalSessionType;
 		this.createdAt = new Date(metadata.startTime);
-		this.title = observableValue('title', metadata.summary ?? `Session ${rawId.substring(0, 8)}`);
+		this.title = observableValue('title', metadata.summary || `Session ${rawId.substring(0, 8)}`);
 		this.updatedAt = observableValue('updatedAt', new Date(metadata.modifiedTime));
 		this.modelId = observableValue<string | undefined>('modelId', metadata.model ? `${resourceScheme}:${metadata.model}` : undefined);
 		this.lastTurnEnd = observableValue('lastTurnEnd', metadata.modifiedTime ? new Date(metadata.modifiedTime) : undefined);
@@ -214,7 +214,7 @@ class RemoteSessionAdapter implements IChatData {
 	}
 
 	update(metadata: IAgentSessionMetadata): void {
-		this.title.set(metadata.summary ?? this.title.get(), undefined);
+		this.title.set(metadata.summary || this.title.get(), undefined);
 		this.updatedAt.set(new Date(metadata.modifiedTime), undefined);
 		this.lastTurnEnd.set(metadata.modifiedTime ? new Date(metadata.modifiedTime) : undefined, undefined);
 		if (metadata.isRead !== undefined) {

src/vs/workbench/contrib/chat/browser/agentSessions/agentHost/agentHostSessionListController.ts

@@ -171,7 +171,7 @@ export class AgentHostSessionListController extends Disposable implements IChatS
 	}): IChatSessionItem {
 		return {
 			resource: URI.from({ scheme: this._sessionType, path: `/${rawId}` }),
-			label: opts.title ?? `Session ${rawId.substring(0, 8)}`,
+			label: opts.title || `Session ${rawId.substring(0, 8)}`,
 			description: this._description,
 			iconPath: getAgentHostIcon(this._productService),
 			status: mapSessionStatus(opts.status),