Make chat sessions give a delta of what has changed

For #300770
2026-07-08 07:44:33 +01:00 · 2026-03-11 16:39:13 -07:00
parent fe7157a1f3
commit ee699b749f
14 changed files with 223 additions and 133 deletions
@@ -22,7 +22,7 @@ import { URI } from '../../base/common/uri.js';
 import { Disposable } from '../../base/common/lifecycle.js';
 import { IWorkbenchContribution, registerWorkbenchContribution2, WorkbenchPhase } from '../../workbench/common/contributions.js';
 import { IChatProgress } from '../../workbench/contrib/chat/common/chatService/chatService.js';
-import { IChatSessionsService, IChatSessionItem, IChatSessionFileChange, ChatSessionStatus, IChatSessionHistoryItem } from '../../workbench/contrib/chat/common/chatSessionsService.js';
+import { IChatSessionsService, IChatSessionItem, IChatSessionFileChange, ChatSessionStatus, IChatSessionHistoryItem, IChatSessionItemsDelta } from '../../workbench/contrib/chat/common/chatSessionsService.js';
 import { IGitService, IGitExtensionDelegate, IGitRepository } from '../../workbench/contrib/git/common/gitService.js';
 import { IFileService } from '../../platform/files/common/files.js';
 import { InMemoryFileSystemProvider } from '../../platform/files/common/inMemoryFilesystemProvider.js';
@@ -228,7 +228,7 @@ class MockChatAgentContribution extends Disposable implements IWorkbenchContribu
 	static readonly ID = 'sessions.test.mockChatAgent';

 	private readonly _sessionItems: IChatSessionItem[] = [];
-	private readonly _itemsChangedEmitter = new Emitter<void>();
+	private readonly _itemsChangedEmitter = new Emitter<IChatSessionItemsDelta>();
 	private readonly _sessionHistory = new Map<string, IChatSessionHistoryItem[]>();

 	constructor(
@@ -273,6 +273,7 @@ class MockChatAgentContribution extends Disposable implements IWorkbenchContribu

 		// Add or update session in list
 		const existing = this._sessionItems.find(s => s.resource.toString() === key);
+		let addedOrUpdated: IChatSessionItem | undefined = existing;
 		if (existing) {
 			existing.timing.lastRequestStarted = now;
 			existing.timing.lastRequestEnded = now;
@@ -280,15 +281,19 @@ class MockChatAgentContribution extends Disposable implements IWorkbenchContribu
 				existing.changes = changes;
 			}
 		} else {
-			this._sessionItems.push({
+			addedOrUpdated = {
 				resource,
 				label: message.slice(0, 50) || 'Mock Session',
 				status: ChatSessionStatus.Completed,
 				timing: { created: now, lastRequestStarted: now, lastRequestEnded: now },
 				...(changes ? { changes } : {}),
-			});
+			};
+			this._sessionItems.push(addedOrUpdated);
+		}
+
+		if (addedOrUpdated) {
+			this._itemsChangedEmitter.fire({ addedOrUpdated: [addedOrUpdated] });
 		}
-		this._itemsChangedEmitter.fire();
 	}

 	private registerMockAgents(): void {
@@ -15,6 +15,7 @@ import { isEqual } from '../../../base/common/resources.js';
 import { URI, UriComponents } from '../../../base/common/uri.js';
 import { localize } from '../../../nls.js';
 import { IDialogService } from '../../../platform/dialogs/common/dialogs.js';
+import { IInstantiationService } from '../../../platform/instantiation/common/instantiation.js';
 import { ILogService } from '../../../platform/log/common/log.js';
 import { hasValidDiff, IAgentSession } from '../../contrib/chat/browser/agentSessions/agentSessionsModel.js';
 import { IAgentSessionsService } from '../../contrib/chat/browser/agentSessions/agentSessionsService.js';
@@ -24,7 +25,7 @@ import { ChatEditorInput } from '../../contrib/chat/browser/widgetHosts/editor/c
 import { IChatRequestVariableEntry } from '../../contrib/chat/common/attachments/chatVariableEntries.js';
 import { awaitStatsForSession } from '../../contrib/chat/common/chat.js';
 import { IChatContentInlineReference, IChatProgress, IChatService, ResponseModelState } from '../../contrib/chat/common/chatService/chatService.js';
-import { ChatSessionStatus, IChatNewSessionRequest, IChatSession, IChatSessionContentProvider, IChatSessionHistoryItem, IChatSessionItem, IChatSessionItemController, IChatSessionProviderOptionItem, IChatSessionsService } from '../../contrib/chat/common/chatSessionsService.js';
+import { ChatSessionStatus, IChatNewSessionRequest, IChatSession, IChatSessionContentProvider, IChatSessionHistoryItem, IChatSessionItem, IChatSessionItemController, IChatSessionItemsDelta, IChatSessionProviderOptionItem, IChatSessionsService } from '../../contrib/chat/common/chatSessionsService.js';
 import { ChatAgentLocation } from '../../contrib/chat/common/constants.js';
 import { IChatModel } from '../../contrib/chat/common/model/chatModel.js';
 import { isUntitledChatSession } from '../../contrib/chat/common/model/chatUri.js';
@@ -329,16 +330,25 @@ class MainThreadChatSessionItemController extends Disposable implements IChatSes
 	private readonly _proxy: ExtHostChatSessionsShape;
 	private readonly _handle: number;

-	private readonly _onDidChangeChatSessionItems = this._register(new Emitter<void>());
+	private readonly _onDidChangeChatSessionItems = this._register(new Emitter<IChatSessionItemsDelta>());
 	public readonly onDidChangeChatSessionItems = this._onDidChangeChatSessionItems.event;

 	constructor(
 		proxy: ExtHostChatSessionsShape,
-		handle: number
+		chatSessionType: string,
+		handle: number,
+		@IChatService chatService: IChatService,
 	) {
 		super();
 		this._proxy = proxy;
 		this._handle = handle;
+
+		this._register(chatService.registerChatModelChangeListeners(chatSessionType, (sessionResource) => {
+			const item = this._items.get(sessionResource);
+			if (item) {
+				this._onDidChangeChatSessionItems.fire({ addedOrUpdated: [item] });
+			}
+		}));
 	}

 	private readonly _items = new ResourceMap<IChatSessionItem>();
@@ -361,7 +371,9 @@ class MainThreadChatSessionItemController extends Disposable implements IChatSes
 			changes: revive(dto.changes),
 		};
 		this._items.set(item.resource, item);
-		this._onDidChangeChatSessionItems.fire();
+		this._onDidChangeChatSessionItems.fire({
+			addedOrUpdated: [item],
+		});
 		return item;
 	}

@@ -373,17 +385,18 @@ class MainThreadChatSessionItemController extends Disposable implements IChatSes
 		for (const uri of change.removed) {
 			this._items.delete(uri);
 		}
-		this._onDidChangeChatSessionItems.fire();
+		this._onDidChangeChatSessionItems.fire({
+			addedOrUpdated: change.addedOrUpdated,
+			removed: change.removed,
+		});
 	}

 	addOrUpdateItem(item: IChatSessionItem): void {
 		warnOnUntitledSessionResource(item.resource);
 		this._items.set(item.resource, item);
-		this._onDidChangeChatSessionItems.fire();
-	}
-
-	fireOnDidChangeChatSessionItems(): void {
-		this._onDidChangeChatSessionItems.fire();
+		this._onDidChangeChatSessionItems.fire({
+			addedOrUpdated: [item],
+		});
 	}
 }

@@ -413,6 +426,7 @@ export class MainThreadChatSessions extends Disposable implements MainThreadChat
 		@IEditorService private readonly _editorService: IEditorService,
 		@IEditorGroupsService private readonly editorGroupService: IEditorGroupsService,
 		@ILogService private readonly _logService: ILogService,
+		@IInstantiationService private readonly _instantiationService: IInstantiationService,
 	) {
 		super();

@@ -446,7 +460,7 @@ export class MainThreadChatSessions extends Disposable implements MainThreadChat
 	$registerChatSessionItemController(handle: number, chatSessionType: string): void {
 		const disposables = new DisposableStore();

-		const controller = disposables.add(new MainThreadChatSessionItemController(this._proxy, handle));
+		const controller = disposables.add(this._instantiationService.createInstance(MainThreadChatSessionItemController, this._proxy, chatSessionType, handle));
 		disposables.add(this._chatSessionsService.registerChatSessionItemController(chatSessionType, controller));

 		this._itemControllerRegistrations.set(handle, {
@@ -454,11 +468,6 @@ export class MainThreadChatSessions extends Disposable implements MainThreadChat
 			controller,
 			dispose: () => disposables.dispose(),
 		});
-
-		disposables.add(this._chatService.registerChatModelChangeListeners(
-			chatSessionType,
-			() => controller.fireOnDidChangeChatSessionItems()
-		));
 	}

 	private getController(handle: number): MainThreadChatSessionItemController {
@@ -469,11 +478,6 @@ export class MainThreadChatSessions extends Disposable implements MainThreadChat
 		return registration.controller;
 	}

-	$onDidChangeChatSessionItems(handle: number): void {
-		const controller = this.getController(handle);
-		controller.fireOnDidChangeChatSessionItems();
-	}
-
 	private async _resolveSessionItem(item: Dto<IChatSessionItem>): Promise<IChatSessionItem> {
 		const uri = URI.revive(item.resource);
 		const model = this._chatService.getSession(uri);
@@ -3587,7 +3587,6 @@ export interface MainThreadChatSessionsShape extends IDisposable {
 	$unregisterChatSessionItemController(controllerHandle: number): void;
 	$updateChatSessionItems(controllerHandle: number, change: IChatSessionItemsChange): Promise<void>;
 	$addOrUpdateChatSessionItem(controllerHandle: number, item: Dto<IChatSessionItem>): Promise<void>;
-	$onDidChangeChatSessionItems(controllerHandle: number): void;
 	$onDidCommitChatSessionItem(controllerHandle: number, original: UriComponents, modified: UriComponents): void;
 	$registerChatSessionContentProvider(handle: number, chatSessionScheme: string): void;
 	$unregisterChatSessionContentProvider(handle: number): void;
@@ -27,6 +27,7 @@ import { IChatEntitlementService } from '../../../../services/chat/common/chatEn
 import { ILifecycleService } from '../../../../services/lifecycle/common/lifecycle.js';
 import { Extensions, IOutputChannelRegistry, IOutputService } from '../../../../services/output/common/output.js';
 import { ChatSessionStatus as AgentSessionStatus, IChatSessionFileChange, IChatSessionFileChange2, IChatSessionItem, IChatSessionsService, ResolvedChatSessionsExtensionPoint } from '../../common/chatSessionsService.js';
+import { getChatSessionType } from '../../common/model/chatUri.js';
 import { IChatWidgetService } from '../chat.js';
 import { AgentSessionProviders, getAgentSessionProvider, getAgentSessionProviderIcon, getAgentSessionProviderName, isBuiltInAgentSessionProvider } from './agentSessions.js';

@@ -434,7 +435,19 @@ export class AgentSessionsModel extends Disposable implements IAgentSessionsMode
 		// Sessions updates
 		this._register(this.chatSessionsService.onDidChangeItemsProviders(({ chatSessionType }) => this.resolve(chatSessionType)));
 		this._register(this.chatSessionsService.onDidChangeAvailability(() => this.resolve(undefined)));
-		this._register(this.chatSessionsService.onDidChangeSessionItems(({ chatSessionType }) => this.updateItems([chatSessionType], CancellationToken.None)));
+		this._register(this.chatSessionsService.onDidChangeSessionItems((delta) => {
+			const changedChatSessionTypes = new Set<string>();
+
+			for (const resource of delta.addedOrUpdated ?? []) {
+				changedChatSessionTypes.add(getChatSessionType(resource.resource));
+			}
+
+			for (const resource of delta.removed ?? []) {
+				changedChatSessionTypes.add(getChatSessionType(resource));
+			}
+
+			this.updateItems(Array.from(changedChatSessionTypes), CancellationToken.None);
+		}));
 		this._register(this.workspaceContextService.onDidChangeWorkspaceFolders(() => this.resolve(undefined)));
 		this._register(this.workspaceTrustManagementService.onDidChangeTrust(() => this.resolve(undefined)));

@@ -10,12 +10,14 @@ import { Emitter } from '../../../../../base/common/event.js';
 import { Disposable } from '../../../../../base/common/lifecycle.js';
 import { ResourceSet } from '../../../../../base/common/map.js';
 import { Schemas } from '../../../../../base/common/network.js';
-import { IWorkbenchContribution } from '../../../../common/contributions.js';
-import { IChatModel } from '../../common/model/chatModel.js';
-import { convertLegacyChatSessionTiming, IChatDetail, IChatService, ResponseModelState } from '../../common/chatService/chatService.js';
-import { ChatSessionStatus, IChatSessionItem, IChatSessionItemController, IChatSessionsService, localChatSessionType } from '../../common/chatSessionsService.js';
-import { getChatSessionType } from '../../common/model/chatUri.js';
+import { isEqual } from '../../../../../base/common/resources.js';
+import { URI } from '../../../../../base/common/uri.js';
 import { ILogService } from '../../../../../platform/log/common/log.js';
+import { IWorkbenchContribution } from '../../../../common/contributions.js';
+import { convertLegacyChatSessionTiming, IChatDetail, IChatService, ResponseModelState } from '../../common/chatService/chatService.js';
+import { ChatSessionStatus, IChatSessionItem, IChatSessionItemController, IChatSessionItemsDelta, IChatSessionsService, localChatSessionType } from '../../common/chatSessionsService.js';
+import { IChatModel } from '../../common/model/chatModel.js';
+import { getChatSessionType } from '../../common/model/chatUri.js';

 export class LocalAgentsSessionsController extends Disposable implements IChatSessionItemController, IWorkbenchContribution {

@@ -26,7 +28,7 @@ export class LocalAgentsSessionsController extends Disposable implements IChatSe
 	private readonly _onDidChange = this._register(new Emitter<void>());
 	readonly onDidChange = this._onDidChange.event;

-	readonly _onDidChangeChatSessionItems = this._register(new Emitter<void>());
+	readonly _onDidChangeChatSessionItems = this._register(new Emitter<IChatSessionItemsDelta>());
 	readonly onDidChangeChatSessionItems = this._onDidChangeChatSessionItems.event;

 	constructor(
@@ -51,20 +53,32 @@ export class LocalAgentsSessionsController extends Disposable implements IChatSe
 	}

 	private registerListeners(): void {
-		const refreshItems = async () => {
-			this._onDidChangeChatSessionItems.fire();
-			await this.refresh(CancellationToken.None);
-			this._onDidChangeChatSessionItems.fire();
-		};
+		this._register(this.chatService.registerChatModelChangeListeners(Schemas.vscodeLocalChatSession, async sessionResource => {
+			if (getChatSessionType(sessionResource) !== this.chatSessionType) {
+				return;
+			}

-		this._register(this.chatService.registerChatModelChangeListeners(Schemas.vscodeLocalChatSession, refreshItems));
+			let item = this.getItem(sessionResource);
+			if (!item) {
+				await this.refresh(CancellationToken.None);
+				item = this.getItem(sessionResource);
+			}

-		this._register(this.chatService.onDidDisposeSession(e => {
-			const session = e.sessionResource.filter(resource => getChatSessionType(resource) === this.chatSessionType);
-			if (session.length > 0) {
-				refreshItems();
+			if (item) {
+				this._onDidChangeChatSessionItems.fire({ addedOrUpdated: [item] });
 			}
 		}));
+
+		this._register(this.chatService.onDidDisposeSession(e => {
+			const removedSessionResources = e.sessionResource.filter(resource => getChatSessionType(resource) === this.chatSessionType);
+			if (removedSessionResources.length) {
+				this._onDidChangeChatSessionItems.fire({ removed: removedSessionResources });
+			}
+		}));
+	}
+
+	private getItem(sessionResource: URI): IChatSessionItem | undefined {
+		return this._items.find(item => isEqual(item.resource, sessionResource));
 	}

 	private async provideChatSessionItems(token: CancellationToken): Promise<IChatSessionItem[]> {
@@ -9,7 +9,7 @@ import { CancellationToken, CancellationTokenSource } from '../../../../../base/
 import { Codicon } from '../../../../../base/common/codicons.js';
 import { AsyncEmitter, Emitter, Event } from '../../../../../base/common/event.js';
 import { combinedDisposable, Disposable, DisposableMap, DisposableStore, IDisposable } from '../../../../../base/common/lifecycle.js';
-import { ResourceMap } from '../../../../../base/common/map.js';
+import { ResourceMap, ResourceSet } from '../../../../../base/common/map.js';
 import { Schemas } from '../../../../../base/common/network.js';
 import * as resources from '../../../../../base/common/resources.js';
 import { ThemeIcon } from '../../../../../base/common/themables.js';
@@ -31,7 +31,7 @@ import { ExtensionsRegistry } from '../../../../services/extensions/common/exten
 import { ChatEditorInput } from '../widgetHosts/editor/chatEditorInput.js';
 import { IChatAgentAttachmentCapabilities, IChatAgentData, IChatAgentService } from '../../common/participants/chatAgents.js';
 import { ChatContextKeys } from '../../common/actions/chatContextKeys.js';
-import { IChatNewSessionRequest, IChatSession, IChatSessionContentProvider, IChatSessionItem, IChatSessionItemController, IChatSessionOptionsWillNotifyExtensionEvent, IChatSessionProviderOptionGroup, IChatSessionProviderOptionItem, IChatSessionsExtensionPoint, IChatSessionsService, isSessionInProgressStatus, ResolvedChatSessionsExtensionPoint } from '../../common/chatSessionsService.js';
+import { IChatNewSessionRequest, IChatSession, IChatSessionContentProvider, IChatSessionItem, IChatSessionItemController, IChatSessionItemsDelta, IChatSessionOptionsWillNotifyExtensionEvent, IChatSessionProviderOptionGroup, IChatSessionProviderOptionItem, IChatSessionsExtensionPoint, IChatSessionsService, isSessionInProgressStatus, ResolvedChatSessionsExtensionPoint } from '../../common/chatSessionsService.js';
 import { ChatAgentLocation, ChatModeKind } from '../../common/constants.js';
 import { CHAT_CATEGORY } from '../actions/chatActions.js';
 import { IChatEditorOptions } from '../widgetHosts/editor/chatEditor.js';
@@ -47,7 +47,10 @@ import { ChatViewPane } from '../widgetHosts/viewPane/chatViewPane.js';
 import { AgentSessionProviders, getAgentSessionProviderName } from '../agentSessions/agentSessions.js';
 import { BugIndicatingError, isCancellationError } from '../../../../../base/common/errors.js';
 import { IEditorGroupsService } from '../../../../services/editor/common/editorGroupsService.js';
-import { isUntitledChatSession, LocalChatSessionUri } from '../../common/model/chatUri.js';
+import {
+	getChatSessionType,
+	isUntitledChatSession, LocalChatSessionUri
+} from '../../common/model/chatUri.js';
 import { assertNever } from '../../../../../base/common/assert.js';
 import { ICommandService } from '../../../../../platform/commands/common/commands.js';
 import { Target } from '../../common/promptSyntax/promptTypes.js';
@@ -276,7 +279,7 @@ export class ChatSessionsService extends Disposable implements IChatSessionsServ
 	private readonly _onDidChangeItemsProviders = this._register(new Emitter<{ readonly chatSessionType: string }>());
 	readonly onDidChangeItemsProviders = this._onDidChangeItemsProviders.event;

-	private readonly _onDidChangeSessionItems = this._register(new Emitter<{ readonly chatSessionType: string }>());
+	private readonly _onDidChangeSessionItems = this._register(new Emitter<IChatSessionItemsDelta>());
 	readonly onDidChangeSessionItems = this._onDidChangeSessionItems.event;

 	private readonly _onDidChangeAvailability = this._register(new Emitter<void>());
@@ -350,10 +353,17 @@ export class ChatSessionsService extends Disposable implements IChatSessionsServ
 			}
 		}));

-		this._register(this.onDidChangeSessionItems(({ chatSessionType }) => {
-			this.updateInProgressStatus(chatSessionType).catch(error => {
-				this._logService.warn(`Failed to update progress status for '${chatSessionType}':`, error);
-			});
+		this._register(this.onDidChangeSessionItems((delta) => {
+			const changedChatSessionTypes = new Set<string>();
+			for (const resource of delta.addedOrUpdated ?? []) {
+				changedChatSessionTypes.add(getChatSessionType(resource.resource));
+			}
+
+			for (const chatSessionType of changedChatSessionTypes) {
+				this.updateInProgressStatus(chatSessionType).catch(error => {
+					this._logService.warn(`Failed to update progress status for '${chatSessionType}':`, error);
+				});
+			}
 		}));

 		this._register(this._labelService.registerFormatter({
@@ -597,7 +607,11 @@ export class ChatSessionsService extends Disposable implements IChatSessionsServ
 	}

 	private _evaluateAvailability(): void {
-		let hasChanges = false;
+		const newlyEnabledChatSessionTypes = new Set<string>();
+		const newlyDisabledChatSessionTypes = new Set<string>();
+
+		const disposedChatSessions = new ResourceSet();
+
 		for (const { contribution, extension } of this._contributions.values()) {
 			const isCurrentlyRegistered = this._contributionDisposables.has(contribution.type);
 			const shouldBeRegistered = this._isContributionAvailable(contribution);
@@ -607,21 +621,25 @@ export class ChatSessionsService extends Disposable implements IChatSessionsServ
 				this._contributionDisposables.deleteAndDispose(contribution.type);

 				// Also dispose any cached sessions for this contribution
-				this._disposeSessionsForContribution(contribution.type);
-				hasChanges = true;
+				for (const sessionResource of this._disposeSessionsForContribution(contribution.type)) {
+					disposedChatSessions.add(sessionResource);
+				}
+
+				newlyDisabledChatSessionTypes.add(contribution.type);
 			} else if (!isCurrentlyRegistered && shouldBeRegistered) {
 				// Enable the contribution by registering it
 				this._enableContribution(contribution, extension);
-				hasChanges = true;
+				newlyEnabledChatSessionTypes.add(contribution.type);
 			}
 		}
-		if (hasChanges) {
+		if (newlyEnabledChatSessionTypes.size > 0 || newlyDisabledChatSessionTypes.size > 0) {
 			this._onDidChangeAvailability.fire();
-			for (const chatSessionType of this._itemControllers.keys()) {
+			for (const chatSessionType of [...newlyEnabledChatSessionTypes, ...newlyDisabledChatSessionTypes]) {
 				this._onDidChangeItemsProviders.fire({ chatSessionType });
 			}
-			for (const { contribution } of this._contributions.values()) {
-				this._onDidChangeSessionItems.fire({ chatSessionType: contribution.type });
+
+			if (disposedChatSessions.size > 0) {
+				this._onDidChangeSessionItems.fire({ removed: Array.from(disposedChatSessions) });
 			}
 		}
 		this._updateHasCanDelegateProvidersContextKey();
@@ -638,7 +656,12 @@ export class ChatSessionsService extends Disposable implements IChatSessionsServ
 		disposableStore.add(this._registerMenuItems(contribution, ext));
 	}

-	private _disposeSessionsForContribution(contributionId: string): void {
+	/**
+	 * Disposes of all sessions that belong to a contribution
+	 *
+	 * @returns List of session resources that were disposed.
+	 */
+	private _disposeSessionsForContribution(contributionId: string): URI[] {
 		// Find and dispose all sessions that belong to this contribution
 		const sessionsToDispose: URI[] = [];
 		for (const [sessionResource, sessionData] of this._sessions) {
@@ -657,6 +680,7 @@ export class ChatSessionsService extends Disposable implements IChatSessionsServ
 				sessionData.dispose(); // This will call _onWillDisposeSession and clean up
 			}
 		}
+		return sessionsToDispose;
 	}

 	private _registerAgent(contribution: IChatSessionsExtensionPoint, ext: IRelaxedExtensionDescription): IDisposable {
@@ -866,8 +890,8 @@ export class ChatSessionsService extends Disposable implements IChatSessionsServ
 		this._itemControllers.set(chatSessionType, { controller, initialRefresh: controller.refresh(initialRefreshCts.token) });
 		this._onDidChangeItemsProviders.fire({ chatSessionType });

-		disposables.add(controller.onDidChangeChatSessionItems(() => {
-			this._onDidChangeSessionItems.fire({ chatSessionType });
+		disposables.add(controller.onDidChangeChatSessionItems(e => {
+			this._onDidChangeSessionItems.fire(e);
 		}));

 		this.updateInProgressStatus(chatSessionType).catch(error => {
@@ -14,7 +14,7 @@ import { ICommandService } from '../../../../../platform/commands/common/command
 import { ILogService } from '../../../../../platform/log/common/log.js';
 import { IStorageService, StorageScope, StorageTarget } from '../../../../../platform/storage/common/storage.js';
 import { ILifecycleService, LifecyclePhase } from '../../../../services/lifecycle/common/lifecycle.js';
-import { ChatSessionStatus, IChatSessionItem, IChatSessionItemController, IChatSessionsService } from '../../common/chatSessionsService.js';
+import { ChatSessionStatus, IChatSessionItem, IChatSessionItemController, IChatSessionItemsDelta, IChatSessionsService } from '../../common/chatSessionsService.js';
 import { AgentSessionProviders } from '../agentSessions/agentSessions.js';
 import { IAgentSession } from '../agentSessions/agentSessionsModel.js';
 import { ISessionOpenerParticipant, ISessionOpenOptions, sessionOpenerRegistry } from '../agentSessions/agentSessionsOpener.js';
@@ -36,8 +36,8 @@ export class GrowthSessionController extends Disposable implements IChatSessionI

 	private static readonly SESSION_URI = URI.from({ scheme: AgentSessionProviders.Growth, path: '/growth-welcome' });

-	private readonly _onDidChangeChatSessionItems = this._register(new Emitter<void>());
-	readonly onDidChangeChatSessionItems: Event<void> = this._onDidChangeChatSessionItems.event;
+	private readonly _onDidChangeChatSessionItems = this._register(new Emitter<IChatSessionItemsDelta>());
+	readonly onDidChangeChatSessionItems = this._onDidChangeChatSessionItems.event;

 	private readonly _onDidDismiss = this._register(new Emitter<void>());
 	readonly onDidDismiss: Event<void> = this._onDidDismiss.event;
@@ -103,7 +103,9 @@ export class GrowthSessionController extends Disposable implements IChatSessionI
 		this.storageService.store(GrowthSessionController.STORAGE_KEY, true, StorageScope.APPLICATION, StorageTarget.USER);

 		// Fire change event first so that listeners (like the model) see empty items
-		this._onDidChangeChatSessionItems.fire();
+		this._onDidChangeChatSessionItems.fire({
+			removed: [GrowthSessionController.SESSION_URI],
+		});
 		// Then fire dismiss event which triggers unregistration of the controller.
 		this._onDidDismiss.fire();
 	}
@@ -1499,7 +1499,7 @@ export interface IChatService {
 	readonly onDidReceiveQuestionCarouselAnswer: Event<{ requestId: string; resolveId: string; answers: IChatQuestionAnswers | undefined }>;
 	notifyQuestionCarouselAnswer(requestId: string, resolveId: string, answers: IChatQuestionAnswers | undefined): void;

-	readonly onDidDisposeSession: Event<{ readonly sessionResource: URI[]; readonly reason: 'cleared' }>;
+	readonly onDidDisposeSession: Event<{ readonly sessionResource: readonly URI[]; readonly reason: 'cleared' }>;

 	transferChatSession(transferredSessionResource: URI, toWorkspace: URI): Promise<void>;

@@ -1510,7 +1510,7 @@ export interface IChatService {
 	/**
 	 * @deprecated
 	 */
-	registerChatModelChangeListeners(chatSessionType: string, onChange: () => void): IDisposable;
+	registerChatModelChangeListeners(chatSessionType: string, onChange: (chatSessionResource: URI) => void): IDisposable;

 	/**
 	 * For tests only!
@@ -1615,7 +1615,7 @@ export class ChatService extends Disposable implements IChatService {
 		return localSessionId;
 	}

-	public registerChatModelChangeListeners(chatSessionType: string, onChange: () => void): IDisposable {
+	public registerChatModelChangeListeners(chatSessionType: string, onChange: (chatSessionResource: URI) => void): IDisposable {
 		const disposableStore = new DisposableStore();
 		const chatModelsICareAbout = this.chatModels.map(models =>
 			Array.from(models).filter((model: IChatModel) => model.sessionResource.scheme === chatSessionType)
@@ -1638,7 +1638,7 @@ export class ChatService extends Disposable implements IChatService {
 					listeners.set(added.sessionResource, autorun(reader => {
 						requestChangeListener.read(reader)?.read(reader);
 						modelChangeListener.read(reader);
-						onChange();
+						onChange(added.sessionResource);
 					}));
 				});
 			}
@@ -198,9 +198,14 @@ export interface IChatNewSessionRequest {
 	readonly command?: string;
 }

+export interface IChatSessionItemsDelta {
+	readonly addedOrUpdated?: readonly IChatSessionItem[];
+	readonly removed?: readonly URI[];
+}
+
 export interface IChatSessionItemController {

-	readonly onDidChangeChatSessionItems: Event<void>;
+	readonly onDidChangeChatSessionItems: Event<IChatSessionItemsDelta>;

 	get items(): readonly IChatSessionItem[];

@@ -229,7 +234,7 @@ export interface IChatSessionsService {

 	// #region Chat session item provider support
 	readonly onDidChangeItemsProviders: Event<{ readonly chatSessionType: string }>;
-	readonly onDidChangeSessionItems: Event<{ readonly chatSessionType: string }>;
+	readonly onDidChangeSessionItems: Event<IChatSessionItemsDelta>;

 	readonly onDidChangeAvailability: Event<void>;
 	readonly onDidChangeInProgress: Event<void>;
@@ -77,7 +77,7 @@ suite('AgentSessions', () => {

 		test('should resolve sessions from controllers', async () => {
 			return runWithFakedTimers({}, async () => {
-				const chatSessionType = 'test-type';
+				const chatSessionType = chatSessionTestType;
 				const controller = new StaticChatSessionItemController([
 					makeSimpleSessionItem('session-1', {
 						label: 'Test Session 1'
@@ -93,9 +93,9 @@ suite('AgentSessions', () => {
 				await viewModel.resolve(undefined);

 				assert.strictEqual(viewModel.sessions.length, 2);
-				assert.strictEqual(viewModel.sessions[0].resource.toString(), 'test://session-1');
+				assert.strictEqual(viewModel.sessions[0].resource.toString(), `${chatSessionTestType}://session-1`);
 				assert.strictEqual(viewModel.sessions[0].label, 'Test Session 1');
-				assert.strictEqual(viewModel.sessions[1].resource.toString(), 'test://session-2');
+				assert.strictEqual(viewModel.sessions[1].resource.toString(), `${chatSessionTestType}://session-2`);
 				assert.strictEqual(viewModel.sessions[1].label, 'Test Session 2');
 			});
 		});
@@ -114,8 +114,8 @@ suite('AgentSessions', () => {
 				await viewModel.resolve(undefined);

 				assert.strictEqual(viewModel.sessions.length, 2);
-				assert.strictEqual(viewModel.sessions[0].resource.toString(), 'test://session-1');
-				assert.strictEqual(viewModel.sessions[1].resource.toString(), 'test://session-2');
+				assert.strictEqual(viewModel.sessions[0].resource.toString(), `${chatSessionTestType}://session-1`);
+				assert.strictEqual(viewModel.sessions[1].resource.toString(), `${chatSessionTestType}://session-2`);
 			});
 		});

@@ -123,7 +123,7 @@ suite('AgentSessions', () => {
 			return runWithFakedTimers({}, async () => {
 				const controller = new StaticChatSessionItemController([]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = createViewModel();

 				let willResolveFired = false;
@@ -150,7 +150,7 @@ suite('AgentSessions', () => {
 			return runWithFakedTimers({}, async () => {
 				const controller = new StaticChatSessionItemController([makeSimpleSessionItem('session-1')]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = createViewModel();

 				let sessionsChangedFired = false;
@@ -180,7 +180,7 @@ suite('AgentSessions', () => {
 					changes: { files: 1, insertions: 10, deletions: 5 }
 				}]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = createViewModel();

 				await viewModel.resolve(undefined);
@@ -241,7 +241,7 @@ suite('AgentSessions', () => {

 		test('should respond to onDidChangeItemsProviders event', async () => {
 			return runWithFakedTimers({}, async () => {
-				const chatSessionType = 'test-type';
+				const chatSessionType = chatSessionTestType;
 				const controller = new StaticChatSessionItemController([makeSimpleSessionItem('session-1')]);

 				mockChatSessionsService.registerChatSessionItemController(chatSessionType, controller);
@@ -263,7 +263,7 @@ suite('AgentSessions', () => {
 			return runWithFakedTimers({}, async () => {
 				const controller = new StaticChatSessionItemController([makeSimpleSessionItem('session-1')]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = createViewModel();

 				const sessionsChangedPromise = Event.toPromise(viewModel.onDidChangeSessions);
@@ -280,15 +280,16 @@ suite('AgentSessions', () => {

 		test('should respond to onDidChangeSessionItems event', async () => {
 			return runWithFakedTimers({}, async () => {
-				const controller = new StaticChatSessionItemController([makeSimpleSessionItem('session-1')]);
+				const testSession = makeSimpleSessionItem('session-1');
+				const controller = new StaticChatSessionItemController([testSession]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = createViewModel();

 				const sessionsChangedPromise = Event.toPromise(viewModel.onDidChangeSessions);

 				// Trigger event - this should automatically call resolve
-				mockChatSessionsService.fireDidChangeSessionItems('test-type');
+				mockChatSessionsService.fireDidChangeSessionItems({ addedOrUpdated: [testSession] });

 				// Wait for the sessions to be resolved
 				await sessionsChangedPromise;
@@ -301,13 +302,13 @@ suite('AgentSessions', () => {
 			return runWithFakedTimers({}, async () => {
 				const controller = new StaticChatSessionItemController([makeSimpleSessionItem('session-1')]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = createViewModel();

 				await viewModel.resolve(undefined);

 				assert.strictEqual(viewModel.sessions.length, 1);
-				assert.strictEqual(viewModel.sessions[0].providerType, 'test-type');
+				assert.strictEqual(viewModel.sessions[0].providerType, chatSessionTestType);
 			});
 		});

@@ -315,7 +316,7 @@ suite('AgentSessions', () => {
 			return runWithFakedTimers({}, async () => {
 				const controller = new StaticChatSessionItemController([]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = createViewModel();

 				await viewModel.resolve(undefined);
@@ -347,7 +348,7 @@ suite('AgentSessions', () => {
 					}
 				]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = createViewModel();

 				await viewModel.resolve(undefined);
@@ -375,7 +376,7 @@ suite('AgentSessions', () => {
 					get items() { return _items; }
 				};

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = createViewModel();

 				await viewModel.resolve(undefined);
@@ -415,7 +416,7 @@ suite('AgentSessions', () => {
 					timing: makeNewSessionTiming()
 				}]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = createViewModel();

 				await viewModel.resolve(undefined);
@@ -437,7 +438,7 @@ suite('AgentSessions', () => {
 					}
 				};

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				// Registering calls a refresh initially
 				assert.strictEqual(controllerCallCount, 1);

@@ -669,7 +670,7 @@ suite('AgentSessions', () => {

 		function createSession(overrides: Partial<IAgentSession> = {}): IAgentSession {
 			return {
-				providerType: 'test-type',
+				providerType: chatSessionTestType,
 				providerLabel: 'Test Provider',
 				icon: Codicon.chatSparkle,
 				resource: URI.parse('test://session'),
@@ -1214,7 +1215,7 @@ suite('AgentSessions', () => {
 			return runWithFakedTimers({}, async () => {
 				const controller = new StaticChatSessionItemController([makeSimpleSessionItem('session-1')]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1236,7 +1237,7 @@ suite('AgentSessions', () => {
 			return runWithFakedTimers({}, async () => {
 				const controller = new StaticChatSessionItemController([makeSimpleSessionItem('session-1')]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1256,7 +1257,7 @@ suite('AgentSessions', () => {
 			return runWithFakedTimers({}, async () => {
 				const controller = new StaticChatSessionItemController([makeSimpleSessionItem('session-1')]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1284,7 +1285,7 @@ suite('AgentSessions', () => {
 					timing: makeNewSessionTiming()
 				}]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1303,7 +1304,7 @@ suite('AgentSessions', () => {
 					timing: makeNewSessionTiming()
 				}]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1358,7 +1359,7 @@ suite('AgentSessions', () => {
 					timing: futureSessionTiming,
 				}]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1379,7 +1380,7 @@ suite('AgentSessions', () => {
 			return runWithFakedTimers({}, async () => {
 				const controller = new StaticChatSessionItemController([makeSimpleSessionItem('session-1')]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1401,7 +1402,7 @@ suite('AgentSessions', () => {
 			return runWithFakedTimers({}, async () => {
 				const controller = new StaticChatSessionItemController([makeSimpleSessionItem('session-1')]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1424,7 +1425,7 @@ suite('AgentSessions', () => {
 			return runWithFakedTimers({}, async () => {
 				const controller = new StaticChatSessionItemController([makeSimpleSessionItem('session-1')]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1455,7 +1456,7 @@ suite('AgentSessions', () => {
 					timing: oldSessionTiming,
 				}]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1480,7 +1481,7 @@ suite('AgentSessions', () => {
 					timing: newSessionTiming,
 				}]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1506,7 +1507,7 @@ suite('AgentSessions', () => {
 					timing: sessionTiming,
 				}]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1532,7 +1533,7 @@ suite('AgentSessions', () => {
 					timing: sessionTiming,
 				}]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1557,7 +1558,7 @@ suite('AgentSessions', () => {
 					timing: newSessionTiming,
 				}]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1590,7 +1591,7 @@ suite('AgentSessions', () => {
 					timing: newSessionTiming,
 				}]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1629,7 +1630,7 @@ suite('AgentSessions', () => {
 					timing: newSessionTiming,
 				}]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1659,7 +1660,7 @@ suite('AgentSessions', () => {
 					lastRequestEnded: Date.UTC(2025, 10 /* November */, 2),
 				};

-				const chatSessionType = 'test-type';
+				const chatSessionType = chatSessionTestType;
 				const controller = new StaticChatSessionItemController([{
 					resource: URI.parse('test://old-session'),
 					label: 'Old Session',
@@ -1727,7 +1728,7 @@ suite('AgentSessions', () => {
 					get items() { return _items; }
 				};

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1757,7 +1758,7 @@ suite('AgentSessions', () => {
 					get items() { return _items; }
 				};

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				await viewModel.resolve(undefined);
@@ -1967,7 +1968,7 @@ suite('AgentSessions', () => {
 			return runWithFakedTimers({}, async () => {
 				const controller = new StaticChatSessionItemController([makeSimpleSessionItem('session-1')]);

-				mockChatSessionsService.registerChatSessionItemController('test-type', controller);
+				mockChatSessionsService.registerChatSessionItemController(chatSessionTestType, controller);
 				viewModel = disposables.add(instantiationService.createInstance(AgentSessionsModel));

 				// Set willShutdown to true
@@ -2018,9 +2019,11 @@ suite('AgentSessions', () => {

 }); // End of Agent Sessions suite

+const chatSessionTestType = 'test-type';
+
 function makeSimpleSessionItem(id: string, overrides?: Partial<IChatSessionItem>): IChatSessionItem {
 	return {
-		resource: URI.parse(`test://${id}`),
+		resource: URI.parse(`${chatSessionTestType}://${id}`),
 		label: `Session ${id}`,
 		timing: makeNewSessionTiming(),
 		...overrides
@@ -6,7 +6,7 @@
 import assert from 'assert';
 import { CancellationToken } from '../../../../../../base/common/cancellation.js';
 import { Codicon } from '../../../../../../base/common/codicons.js';
-import { Emitter } from '../../../../../../base/common/event.js';
+import { Emitter, Event } from '../../../../../../base/common/event.js';
 import { DisposableStore } from '../../../../../../base/common/lifecycle.js';
 import { observableValue } from '../../../../../../base/common/observable.js';
 import { URI } from '../../../../../../base/common/uri.js';
@@ -585,14 +585,25 @@ suite('LocalAgentsSessionsController', () => {

 				// Add the session first
 				mockChatService.addSession(mockModel);
+				mockChatService.setLiveSessionItems([{
+					sessionResource,
+					title: 'Test Session',
+					lastMessageDate: Date.now(),
+					isActive: true,
+					timing: createTestTiming(),
+					lastResponseState: ResponseModelState.Complete
+				}]);

 				let changeEventCount = 0;
 				disposables.add(controller.onDidChangeChatSessionItems(() => {
 					changeEventCount++;
 				}));

+				const onDidChangeChatSessionItems = Event.toPromise(controller.onDidChangeChatSessionItems);
+
 				// Simulate progress change by triggering the progress listener
-				mockChatService.triggerProgressEvent();
+				mockChatService.triggerProgressEvent(sessionResource);
+				await onDidChangeChatSessionItems;

 				assert.strictEqual(changeEventCount, 1);
 			});
@@ -611,15 +622,26 @@ suite('LocalAgentsSessionsController', () => {

 				// Add the session first
 				mockChatService.addSession(mockModel);
+				mockChatService.setLiveSessionItems([{
+					sessionResource,
+					title: 'Test Session',
+					lastMessageDate: Date.now(),
+					isActive: true,
+					timing: createTestTiming(),
+					lastResponseState: ResponseModelState.Complete
+				}]);

 				let changeEventCount = 0;
 				disposables.add(controller.onDidChangeChatSessionItems(() => {
 					changeEventCount++;
 				}));

-				// Simulate progress change by triggering the progress listener
-				mockChatService.triggerProgressEvent();
+				const onDidChangeChatSessionItems = Event.toPromise(controller.onDidChangeChatSessionItems);

+				// Simulate progress change by triggering the progress listener
+				mockChatService.triggerProgressEvent(sessionResource);
+
+				await onDidChangeChatSessionItems;
 				assert.strictEqual(changeEventCount, 1);
 			});
 		});
@@ -6,6 +6,7 @@
 import { CancellationToken } from '../../../../../../base/common/cancellation.js';
 import { Emitter, Event } from '../../../../../../base/common/event.js';
 import { IDisposable } from '../../../../../../base/common/lifecycle.js';
+import { ResourceMap } from '../../../../../../base/common/map.js';
 import { ISettableObservable, observableValue } from '../../../../../../base/common/observable.js';
 import { URI } from '../../../../../../base/common/uri.js';
 import { ChatRequestQueueKind, ChatSendResult, IChatDetail, IChatModelReference, IChatProgress, IChatSendRequestOptions, IChatService, IChatSessionContext, IChatSessionStartOptions, IChatUserActionEvent } from '../../../common/chatService/chatService.js';
@@ -22,7 +23,7 @@ export class MockChatService implements IChatService {
 	readonly onDidSubmitRequest = Event.None;
 	readonly onDidCreateModel = Event.None;

-	private sessions = new Map<string, IChatModel>();
+	private readonly sessions = new ResourceMap<IChatModel>();
 	private liveSessionItems: IChatDetail[] = [];
 	private historySessionItems: IChatDetail[] = [];

@@ -50,13 +51,13 @@ export class MockChatService implements IChatService {
 	}

 	addSession(session: IChatModel): void {
-		this.sessions.set(session.sessionResource.toString(), session);
+		this.sessions.set(session.sessionResource, session);
 		// Update the chatModels observable
 		this._chatModels.set([...this.sessions.values()], undefined);
 	}

 	removeSession(sessionResource: URI): void {
-		this.sessions.delete(sessionResource.toString());
+		this.sessions.delete(sessionResource);
 		// Update the chatModels observable
 		this._chatModels.set([...this.sessions.values()], undefined);
 	}
@@ -78,7 +79,7 @@ export class MockChatService implements IChatService {
 	}

 	getSession(sessionResource: URI): IChatModel | undefined {
-		return this.sessions.get(sessionResource.toString());
+		return this.sessions.get(sessionResource);
 	}

 	getLatestRequest(): IChatRequestModel | undefined {
@@ -190,9 +191,9 @@ export class MockChatService implements IChatService {
 	}


-	private onChange?: () => void;
+	private onChange?: (sessionResource: URI) => void;

-	registerChatModelChangeListeners(chatSessionType: string, onChange: () => void): IDisposable {
+	registerChatModelChangeListeners(chatSessionType: string, onChange: (sessionResource: URI) => void): IDisposable {
 		// Store the emitter so tests can trigger it
 		this.onChange = onChange;
 		return {
@@ -203,9 +204,7 @@ export class MockChatService implements IChatService {
 	}

 	// Helper method for tests to trigger progress events
-	triggerProgressEvent(): void {
-		if (this.onChange) {
-			this.onChange();
-		}
+	triggerProgressEvent(sessionResource: URI): void {
+		this.onChange?.(sessionResource);
 	}
 }
@@ -11,7 +11,7 @@ import { ThemeIcon } from '../../../../../base/common/themables.js';
 import { URI } from '../../../../../base/common/uri.js';
 import { IChatAgentAttachmentCapabilities } from '../../common/participants/chatAgents.js';
 import { IChatModel } from '../../common/model/chatModel.js';
-import { IChatNewSessionRequest, IChatSession, IChatSessionContentProvider, IChatSessionItemController, IChatSessionItem, IChatSessionOptionsWillNotifyExtensionEvent, IChatSessionProviderOptionGroup, IChatSessionProviderOptionItem, IChatSessionsExtensionPoint, IChatSessionsService, ResolvedChatSessionsExtensionPoint } from '../../common/chatSessionsService.js';
+import { IChatNewSessionRequest, IChatSession, IChatSessionContentProvider, IChatSessionItemController, IChatSessionItem, IChatSessionOptionsWillNotifyExtensionEvent, IChatSessionProviderOptionGroup, IChatSessionProviderOptionItem, IChatSessionsExtensionPoint, IChatSessionsService, ResolvedChatSessionsExtensionPoint, IChatSessionItemsDelta } from '../../common/chatSessionsService.js';
 import { Target } from '../../common/promptSyntax/promptTypes.js';

 export class MockChatSessionsService implements IChatSessionsService {
@@ -22,7 +22,7 @@ export class MockChatSessionsService implements IChatSessionsService {
 	private readonly _onDidChangeItemsProviders = new Emitter<{ readonly chatSessionType: string }>();
 	readonly onDidChangeItemsProviders = this._onDidChangeItemsProviders.event;

-	private readonly _onDidChangeSessionItems = new Emitter<{ readonly chatSessionType: string }>();
+	private readonly _onDidChangeSessionItems = new Emitter<IChatSessionItemsDelta>();
 	readonly onDidChangeSessionItems = this._onDidChangeSessionItems.event;

 	private readonly _onDidChangeAvailability = new Emitter<void>();
@@ -52,8 +52,8 @@ export class MockChatSessionsService implements IChatSessionsService {
 		this._onDidChangeItemsProviders.fire(event);
 	}

-	fireDidChangeSessionItems(chatSessionType: string): void {
-		this._onDidChangeSessionItems.fire({ chatSessionType });
+	fireDidChangeSessionItems(event: IChatSessionItemsDelta): void {
+		this._onDidChangeSessionItems.fire(event);
 	}

 	fireDidChangeAvailability(): void {