Merge pull request #300818 from microsoft/ben/fancy-muskox

E2E sessions test updates

eslint.config.js

@@ -1965,6 +1965,7 @@ export default tseslint.config(
 						'vs/editor/contrib/*/~',
 						'vs/editor/editor.all.js',
 						'vs/sessions/~',
+						'vs/sessions/services/*/~',
 						'vs/sessions/contrib/*/~',
 						'vs/workbench/~',
 						'vs/workbench/api/~',
@@ -1984,6 +1985,7 @@ export default tseslint.config(
 						'vs/editor/contrib/*/~',
 						'vs/editor/editor.all.js',
 						'vs/sessions/~',
+						'vs/sessions/services/*/~',
 						'vs/sessions/contrib/*/~',
 						'vs/workbench/~',
 						'vs/workbench/api/~',
@@ -2083,6 +2085,7 @@ export default tseslint.config(
 						'vs/editor/contrib/*/~',
 						'vs/workbench/~',
 						'vs/workbench/services/*/~',
+						'vs/sessions/~',
 						'vs/sessions/services/*/~',
 						{
 							'when': 'test',

src/vs/sessions/contrib/terminal/browser/sessionsTerminalContribution.ts

@@ -99,9 +99,14 @@ export class SessionsTerminalContribution extends Disposable implements IWorkben
 		let existing = await this._findTerminalsForKey(key);
 
 		if (existing.length === 0) {
-			existing = [await this._terminalService.createTerminal({ config: { cwd } })];
-			this._terminalService.setActiveInstance(existing[0]);
-			this._logService.trace(`[SessionsTerminal] Created terminal ${existing[0].instanceId} for ${cwd.fsPath}`);
+			try {
+				existing = [await this._terminalService.createTerminal({ config: { cwd } })];
+				this._terminalService.setActiveInstance(existing[0]);
+				this._logService.trace(`[SessionsTerminal] Created terminal ${existing[0].instanceId} for ${cwd.fsPath}`);
+			} catch (e) {
+				this._logService.trace(`[SessionsTerminal] Cannot create terminal for ${cwd.fsPath}: ${e}`);
+				return [];
+			}
 		}
 
 		if (focus) {

src/vs/sessions/services/title/browser/titleService.ts

@@ -0,0 +1,10 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { InstantiationType, registerSingleton } from '../../../../platform/instantiation/common/extensions.js';
+import { ITitleService } from '../../../../workbench/services/title/browser/titleService.js';
+import { TitleService } from '../../../browser/parts/titlebarPart.js';
+
+registerSingleton(ITitleService, TitleService, InstantiationType.Eager);

src/vs/sessions/services/title/electron-browser/titleService.ts

@@ -3,8 +3,8 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { InstantiationType, registerSingleton } from '../../platform/instantiation/common/extensions.js';
-import { ITitleService } from '../../workbench/services/title/browser/titleService.js';
-import { NativeTitleService } from './parts/titlebarPart.js';
+import { InstantiationType, registerSingleton } from '../../../../platform/instantiation/common/extensions.js';
+import { ITitleService } from '../../../../workbench/services/title/browser/titleService.js';
+import { NativeTitleService } from '../../../electron-browser/parts/titlebarPart.js';
 
 registerSingleton(ITitleService, NativeTitleService, InstantiationType.Eager);

src/vs/sessions/sessions.desktop.main.ts

@@ -42,7 +42,7 @@ import '../workbench/services/update/electron-browser/updateService.js';
 import '../workbench/services/url/electron-browser/urlService.js';
 import '../workbench/services/lifecycle/electron-browser/lifecycleService.js';
 import '../workbench/services/host/electron-browser/nativeHostService.js';
-import './electron-browser/titleService.js';
+import './services/title/electron-browser/titleService.js';
 import '../platform/meteredConnection/electron-browser/meteredConnectionService.js';
 import '../workbench/services/request/electron-browser/requestService.js';
 import '../workbench/services/clipboard/electron-browser/clipboardService.js';

src/vs/sessions/sessions.web.main.ts

@@ -90,8 +90,7 @@ import { UserDataAutoSyncService } from '../platform/userDataSync/common/userDat
 import { AccessibilityService } from '../platform/accessibility/browser/accessibilityService.js';
 import { ICustomEndpointTelemetryService } from '../platform/telemetry/common/telemetry.js';
 import { NullEndpointTelemetryService } from '../platform/telemetry/common/telemetryUtils.js';
-import { ITitleService } from '../workbench/services/title/browser/titleService.js';
-import { BrowserTitleService } from '../workbench/browser/parts/titlebar/titlebarPart.js';
+import './services/title/browser/titleService.js';
 import { ITimerService, TimerService } from '../workbench/services/timer/browser/timerService.js';
 import { IDiagnosticsService, NullDiagnosticsService } from '../platform/diagnostics/common/diagnostics.js';
 import { ILanguagePackService } from '../platform/languagePacks/common/languagePacks.js';
@@ -111,7 +110,6 @@ registerSingleton(IUserDataSyncAccountService, UserDataSyncAccountService, Insta
 registerSingleton(IUserDataSyncService, UserDataSyncService, InstantiationType.Delayed);
 registerSingleton(IUserDataSyncResourceProviderService, UserDataSyncResourceProviderService, InstantiationType.Delayed);
 registerSingleton(IUserDataAutoSyncService, UserDataAutoSyncService, InstantiationType.Eager);
-registerSingleton(ITitleService, BrowserTitleService, InstantiationType.Eager);
 registerSingleton(IExtensionTipsService, ExtensionTipsService, InstantiationType.Delayed);
 registerSingleton(ITimerService, TimerService, InstantiationType.Delayed);
 registerSingleton(ICustomEndpointTelemetryService, NullEndpointTelemetryService, InstantiationType.Delayed);
@@ -154,7 +152,9 @@ import './browser/layoutActions.js';
 
 import './contrib/accountMenu/browser/account.contribution.js';
 import './contrib/aiCustomizationTreeView/browser/aiCustomizationTreeView.contribution.js';
+import './contrib/applyCommitsToParentRepo/browser/applyChangesToParentRepo.js';
 import './contrib/chat/browser/chat.contribution.js';
+import './contrib/terminal/browser/sessionsTerminalContribution.js';
 import './contrib/sessions/browser/sessions.contribution.js';
 import './contrib/sessions/browser/customizationsToolbar.contribution.js';
 import './contrib/changes/browser/changesView.contribution.js';

src/vs/sessions/test/e2e/README.md

@@ -21,6 +21,8 @@ runs through the real code paths.
 | Chat agents (`copilotcli`, etc.) | Canned keyword-matched responses with `textEdit` progress items | No real LLM backend |
 | `mock-fs://` FileSystemProvider | `InMemoryFileSystemProvider` registered directly in the workbench (not extension host) | Must be available before any service tries to resolve workspace files |
 | GitHub authentication | Always-signed-in mock provider (extension) | No real OAuth flow |
+| Code Review command | Returns canned review comments per file (extension) | No real Copilot AI review |
+| PR commands (Create/Open/Merge) | No-op handlers that log and show info messages (extension) | No real GitHub API |
 
 ### What's Real (Everything Else)
 
@@ -39,6 +41,10 @@ exercise the actual code paths:
   observations
 - **Menu actions** — "Create PR", "Accept", "Reject" buttons appear based on
   real context key state
+- **`CodeReviewService`** — Orchestrates review requests, processes results from
+  the mock `github.copilot.chat.codeReview.run` command, and stores comments
+- **`CodeReviewToolbarContribution`** — Shows the Code Review button in the
+  Changes view toolbar based on real context key state
 
 ### Data Flow
 
@@ -57,6 +63,26 @@ User types message → Chat Widget → ChatService
 The mock agent is the **only** point where canned data enters the system.
 Everything downstream uses real service implementations.
 
+### Code Review & PR Button Flow
+
+```
+Code Review button clicked → sessions.codeReview.run (core action)
+  → CodeReviewService.requestReview()
+    → commandService.executeCommand('chat.internal.codeReview.run')
+      → Bridge forwards to 'github.copilot.chat.codeReview.run'
+        → Mock extension returns canned comments
+          → CodeReviewService stores results, updates observable state
+            → CodeReviewToolbarContribution updates button icon/badge
+
+Create PR button clicked → github.copilot.chat.createPullRequestCopilotCLIAgentSession.createPR
+  → Mock extension logs and shows info message
+```
+
+The PR buttons (Create PR, Open PR, Merge) are contributed via the mock
+extension's `package.json` menus, gated by `chatSessionType == copilotcli`.
+The `chatSessionType` context key is derived from the session URI scheme
+(`getChatSessionType()`), which returns `copilotcli` for mock sessions.
+
 ### Why the FileSystem Provider Is Registered in the Workbench
 
 The `mock-fs://` `InMemoryFileSystemProvider` is registered directly on

src/vs/sessions/test/e2e/extensions/sessions-e2e-mock/extension.js

@@ -10,7 +10,9 @@
 /**
  * Mock extension for Sessions E2E testing.
  *
- * Provides a fake GitHub authentication provider (skips sign-in).
+ * Provides:
+ * - A fake GitHub authentication provider (skips sign-in)
+ * - Mock command handlers for Code Review, Create PR, Open PR, and Merge
  *
  * The mock-fs:// FileSystemProvider and chat agents are registered
  * directly in the workbench (web.test.ts), not here.
@@ -31,6 +33,9 @@ function activate(context) {
 	// 1. Mock GitHub Authentication Provider
 	context.subscriptions.push(registerMockAuth(vscode));
 
+	// 2. Mock command handlers for Code Review and PR actions
+	context.subscriptions.push(...registerMockCommands(vscode));
+
 	// Note: The mock-fs:// FileSystemProvider is registered directly in the
 	// workbench (web.test.ts → registerMockFileSystemProvider) so it is
 	// available before any service tries to resolve workspace files.
@@ -82,6 +87,88 @@ function registerMockAuth(vscode) {
 	});
 }
 
+// ---------------------------------------------------------------------------
+// Mock Command Handlers (Code Review + PR Actions)
+// ---------------------------------------------------------------------------
+
+/**
+ * Registers mock command handlers that stand in for the real GitHub Copilot
+ * extension commands. These allow the Code Review and Create PR buttons to
+ * function in the e2e test environment.
+ *
+ * @param {typeof import('vscode')} vscode
+ * @returns {import('vscode').Disposable[]}
+ */
+function registerMockCommands(vscode) {
+	const disposables = [];
+
+	// Mock create PR — simulates successful PR creation
+	disposables.push(vscode.commands.registerCommand(
+		'github.copilot.chat.createPullRequestCopilotCLIAgentSession.createPR',
+		() => {
+			console.log('[sessions-e2e-mock] Mock Create PR invoked');
+			vscode.window.showInformationMessage('Mock: Pull request created successfully');
+		}
+	));
+
+	// Mock open PR — simulates opening a PR URL
+	disposables.push(vscode.commands.registerCommand(
+		'github.copilot.chat.openPullRequestCopilotCLIAgentSession.openPR',
+		() => {
+			console.log('[sessions-e2e-mock] Mock Open PR invoked');
+			vscode.window.showInformationMessage('Mock: Opening pull request');
+		}
+	));
+
+	// Mock merge — simulates merging changes
+	disposables.push(vscode.commands.registerCommand(
+		'github.copilot.chat.mergeCopilotCLIAgentSessionChanges.merge',
+		() => {
+			console.log('[sessions-e2e-mock] Mock Merge invoked');
+			vscode.window.showInformationMessage('Mock: Changes merged successfully');
+		}
+	));
+
+	// Mock merge and sync — simulates merging and syncing
+	disposables.push(vscode.commands.registerCommand(
+		'github.copilot.chat.mergeCopilotCLIAgentSessionChanges.mergeAndSync',
+		() => {
+			console.log('[sessions-e2e-mock] Mock Merge and Sync invoked');
+			vscode.window.showInformationMessage('Mock: Changes merged and synced successfully');
+		}
+	));
+
+	// Mock apply changes — simulates applying session changes
+	disposables.push(vscode.commands.registerCommand(
+		'github.copilot.chat.applyCopilotCLIAgentSessionChanges.apply',
+		() => {
+			console.log('[sessions-e2e-mock] Mock Apply Changes invoked');
+			vscode.window.showInformationMessage('Mock: Changes applied successfully');
+		}
+	));
+
+	// Mock checkout PR reroute — simulates checkout PR flow
+	disposables.push(vscode.commands.registerCommand(
+		'github.copilot.chat.checkoutPullRequestReroute',
+		() => {
+			console.log('[sessions-e2e-mock] Mock Checkout PR Reroute invoked');
+			vscode.window.showInformationMessage('Mock: Checking out pull request');
+		}
+	));
+
+	// Mock update changes — simulates updating session changes
+	disposables.push(vscode.commands.registerCommand(
+		'github.copilot.chat.updateCopilotCLIAgentSessionChanges.update',
+		() => {
+			console.log('[sessions-e2e-mock] Mock Update Changes invoked');
+			vscode.window.showInformationMessage('Mock: Changes updated successfully',);
+		}
+	));
+
+	console.log('[sessions-e2e-mock] Registered mock Code Review and PR command handlers');
+	return disposables;
+}
+
 // ---------------------------------------------------------------------------
 // Exports
 // ---------------------------------------------------------------------------

src/vs/sessions/test/e2e/extensions/sessions-e2e-mock/package.json

@@ -10,6 +10,7 @@
 	"extensionKind": ["ui", "workspace"],
 	"browser": "./extension.js",
 	"activationEvents": ["*"],
+	"enabledApiProposals": ["chatSessionsProvider"],
 	"capabilities": {
 		"virtualWorkspaces": true,
 		"untrustedWorkspaces": {
@@ -22,6 +23,88 @@
 				"id": "github",
 				"label": "GitHub (Mock)"
 			}
-		]
+		],
+		"commands": [
+			{
+				"command": "github.copilot.chat.applyCopilotCLIAgentSessionChanges.apply",
+				"title": "Apply Changes",
+				"icon": "$(check)"
+			},
+			{
+				"command": "github.copilot.chat.checkoutPullRequestReroute",
+				"title": "Checkout Pull Request",
+				"icon": "$(git-pull-request)"
+			},
+			{
+				"command": "github.copilot.chat.openPullRequestCopilotCLIAgentSession.openPR",
+				"title": "Open Pull Request",
+				"icon": "$(link-external)"
+			},
+			{
+				"command": "github.copilot.chat.mergeCopilotCLIAgentSessionChanges.merge",
+				"title": "Merge",
+				"icon": "$(git-merge)"
+			},
+			{
+				"command": "github.copilot.chat.mergeCopilotCLIAgentSessionChanges.mergeAndSync",
+				"title": "Merge and Sync",
+				"icon": "$(git-merge)"
+			},
+			{
+				"command": "github.copilot.chat.createPullRequestCopilotCLIAgentSession.createPR",
+				"title": "Create Pull Request",
+				"icon": "$(git-pull-request-create)"
+			},
+			{
+				"command": "github.copilot.chat.updateCopilotCLIAgentSessionChanges.update",
+				"title": "Update",
+				"icon": "$(cloud-upload)"
+			},
+			{
+				"command": "github.copilot.chat.codeReview.run",
+				"title": "Run Code Review"
+			}
+		],
+		"menus": {
+			"chat/input/editing/sessionToolbar": [
+				{
+					"command": "github.copilot.chat.applyCopilotCLIAgentSessionChanges.apply",
+					"when": "chatSessionType == copilotcli && workbenchState != empty && !isSessionsWindow",
+					"group": "navigation@0"
+				},
+				{
+					"command": "github.copilot.chat.checkoutPullRequestReroute",
+					"when": "chatSessionType == copilot-cloud-agent && !github.vscode-pull-request-github.activated && gitOpenRepositoryCount != 0",
+					"group": "navigation@0"
+				},
+				{
+					"command": "github.copilot.chat.openPullRequestCopilotCLIAgentSession.openPR",
+					"when": "chatSessionType == copilotcli && isSessionsWindow && sessions.hasOpenPullRequest",
+					"group": "navigation@1"
+				}
+			],
+			"chat/input/editing/sessionApplyActions": [
+				{
+					"command": "github.copilot.chat.mergeCopilotCLIAgentSessionChanges.merge",
+					"when": "chatSessionType == copilotcli && isSessionsWindow && !sessions.isMergeBaseBranchProtected",
+					"group": "merge@1"
+				},
+				{
+					"command": "github.copilot.chat.mergeCopilotCLIAgentSessionChanges.mergeAndSync",
+					"when": "chatSessionType == copilotcli && isSessionsWindow && !sessions.isMergeBaseBranchProtected",
+					"group": "merge@2"
+				},
+				{
+					"command": "github.copilot.chat.createPullRequestCopilotCLIAgentSession.createPR",
+					"when": "chatSessionType == copilotcli && isSessionsWindow && sessions.isMergeBaseBranchProtected && !sessions.hasOpenPullRequest",
+					"group": "pull_request@1"
+				},
+				{
+					"command": "github.copilot.chat.updateCopilotCLIAgentSessionChanges.update",
+					"when": "chatSessionType == copilotcli && isSessionsWindow",
+					"group": "update@1"
+				}
+			]
+		}
 	}
 }

src/vs/sessions/test/e2e/scenarios/06-full-workflow.scenario.md

@@ -0,0 +1,25 @@
+# Scenario: Full workflow
+
+## Steps
+1. Type "build the project" in the chat input
+2. Press Enter to submit
+3. Verify there is a response in the chat
+4. Toggle the secondary side bar
+5. Verify the changes view shows "CHANGES" with a badge
+6. Verify "package.json" is visible in the changes list
+7. Verify "build.ts" is visible in the changes list
+8. Verify "index.ts" is visible in the changes list
+9. Click on "index.ts" in the changes list
+10. Verify a diff editor opens with modified content
+11. Press Escape to close the diff editor
+12. Verify "Merge" button is visible in changes view header
+13. Verify the "Open Terminal" button is visible
+14. Click the "Open Terminal" button
+15. Verify the terminal panel becomes visible
+16. Verify the terminal tab shows "session-1" in its label
+17. Click "New Session" to create a new session
+18. Type "fix the bug" in the chat input
+19. Press Enter to submit
+20. Verify the terminal tab label changes to show "session-2"
+21. Click back on the first session in the sessions list
+22. Verify the terminal tab label changes back to show "session-1"

src/vs/sessions/test/e2e/scenarios/generated/06-full-workflow.commands.json

@@ -0,0 +1,140 @@
+{
+	"scenario": "Scenario: Full workflow",
+	"generatedAt": "2026-03-12T22:48:50.725Z",
+	"steps": [
+		{
+			"description": "Type \"build the project\" in the chat input",
+			"commands": [
+				"click textbox \"Chat input\"",
+				"type \"build the project\""
+			]
+		},
+		{
+			"description": "Press Enter to submit",
+			"commands": [
+				"press Enter"
+			]
+		},
+		{
+			"description": "Verify there is a response in the chat",
+			"commands": [
+				"# ASSERT_VISIBLE: I'll help you build the project. Here are the changes:"
+			]
+		},
+		{
+			"description": "Toggle the secondary side bar",
+			"commands": [
+				"click button \"Toggle Secondary Side Bar Visibility\""
+			]
+		},
+		{
+			"description": "Verify the changes view shows \"CHANGES\" with a badge",
+			"commands": [
+				"# ASSERT_VISIBLE: Changes - 3 files changed"
+			]
+		},
+		{
+			"description": "Verify \"package.json\" is visible in the changes list",
+			"commands": [
+				"# ASSERT_VISIBLE: package.json"
+			]
+		},
+		{
+			"description": "Verify \"build.ts\" is visible in the changes list",
+			"commands": [
+				"# ASSERT_VISIBLE: build.ts"
+			]
+		},
+		{
+			"description": "Verify \"index.ts\" is visible in the changes list",
+			"commands": [
+				"# ASSERT_VISIBLE: index.ts"
+			]
+		},
+		{
+			"description": "Click on \"index.ts\" in the changes list",
+			"commands": [
+				"click treeitem \"index.ts\""
+			]
+		},
+		{
+			"description": "Verify a diff editor opens with modified content",
+			"commands": [
+				"# ASSERT_VISIBLE: index.ts"
+			]
+		},
+		{
+			"description": "Press Escape to close the diff editor",
+			"commands": [
+				"press Escape"
+			]
+		},
+		{
+			"description": "Verify \"Merge\" button is visible in changes view header",
+			"commands": [
+				"# ASSERT_VISIBLE: Merge"
+			]
+		},
+		{
+			"description": "Verify the \"Open Terminal\" button is visible",
+			"commands": [
+				"# ASSERT_VISIBLE: Open Terminal"
+			]
+		},
+		{
+			"description": "Click the \"Open Terminal\" button",
+			"commands": [
+				"click button \"Open Terminal\""
+			]
+		},
+		{
+			"description": "Verify the terminal panel becomes visible",
+			"commands": [
+				"# ASSERT_VISIBLE: Terminal"
+			]
+		},
+		{
+			"description": "Verify the terminal tab shows \"session-1\" in its label",
+			"commands": [
+				"# ASSERT_VISIBLE: bash - session-1"
+			]
+		},
+		{
+			"description": "Click \"New Session\" to create a new session",
+			"commands": [
+				"click button \"New Session\""
+			]
+		},
+		{
+			"description": "Type \"fix the bug\" in the chat input",
+			"commands": [
+				"click textbox \"Chat input\"",
+				"type \"fix the bug\""
+			]
+		},
+		{
+			"description": "Press Enter to submit",
+			"commands": [
+				"press Enter"
+			]
+		},
+		{
+			"description": "Verify the terminal tab label changes to show \"session-2\"",
+			"commands": [
+				"# ASSERT_VISIBLE: bash - session-2"
+			]
+		},
+		{
+			"description": "Click back on the first session in the sessions list",
+			"commands": [
+				"click listitem \"build the project\""
+			]
+		},
+		{
+			"description": "Verify the terminal tab label changes back to show \"session-1\"",
+			"commands": [
+				"# ASSERT_VISIBLE: bash - session-1"
+			]
+		}
+	]
+}

src/vs/sessions/test/web.test.ts

@@ -25,6 +25,10 @@ import { IChatProgress } from '../../workbench/contrib/chat/common/chatService/c
 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 { ITerminalService } from '../../workbench/contrib/terminal/browser/terminal.js';
+import { ITerminalBackend, ITerminalBackendRegistry, IProcessReadyEvent, IProcessProperty, ProcessPropertyType, TerminalExtensions, ITerminalProcessOptions, IShellLaunchConfig } from '../../platform/terminal/common/terminal.js';
+import { IProcessEnvironment } from '../../base/common/platform.js';
+import { Registry } from '../../platform/registry/common/platform.js';
 import { InMemoryFileSystemProvider } from '../../platform/files/common/inMemoryFilesystemProvider.js';
 import { VSBuffer } from '../../base/common/buffer.js';
 
@@ -230,16 +234,19 @@ class MockChatAgentContribution extends Disposable implements IWorkbenchContribu
 	private readonly _sessionItems: IChatSessionItem[] = [];
 	private readonly _itemsChangedEmitter = new Emitter<IChatSessionItemsDelta>();
 	private readonly _sessionHistory = new Map<string, IChatSessionHistoryItem[]>();
+	private _worktreeCounter = 0;
 
 	constructor(
 		@IChatAgentService private readonly chatAgentService: IChatAgentService,
 		@IStorageService private readonly storageService: IStorageService,
 		@IChatSessionsService private readonly chatSessionsService: IChatSessionsService,
+		@ITerminalService private readonly terminalService: ITerminalService,
 	) {
 		super();
 		this._register(this._itemsChangedEmitter);
 		this.registerMockAgents();
 		this.registerMockSessionProvider();
+		this.registerMockTerminalBackend();
 		this.preseedFolder();
 	}
 
@@ -286,6 +293,7 @@ class MockChatAgentContribution extends Disposable implements IWorkbenchContribu
 				label: message.slice(0, 50) || 'Mock Session',
 				status: ChatSessionStatus.Completed,
 				timing: { created: now, lastRequestStarted: now, lastRequestEnded: now },
+				metadata: { worktreePath: `/mock-worktrees/session-${++this._worktreeCounter}` },
 				...(changes ? { changes } : {}),
 			};
 			this._sessionItems.push(addedOrUpdated);
@@ -311,7 +319,7 @@ class MockChatAgentContribution extends Disposable implements IWorkbenchContribu
 				extensionVersion: '0.0.1',
 				extensionPublisherId: 'vscode',
 				extensionDisplayName: 'Sessions E2E Mock',
-				isDefault: true,
+				isDefault: agentId === 'copilotcli',
 				metadata: {},
 				slashCommands: [],
 				locations: [ChatAgentLocation.Chat],
@@ -385,11 +393,15 @@ class MockChatAgentContribution extends Disposable implements IWorkbenchContribu
 					},
 				}));
 
-				// Register an item controller so sessions appear in the sidebar list
-				const items = this._sessionItems;
+				// Register an item controller so sessions appear in the sidebar list.
+				// Only copilotcli (Background) sessions need real items — the
+				// copilot-cloud-agent controller must return an empty array to
+				// prevent it from overwriting sessions with the wrong providerType
+				// during a full model resolve.
+				const controllerItems = scheme === 'copilotcli' ? this._sessionItems : [];
 				this._register(this.chatSessionsService.registerChatSessionItemController(scheme, {
 					onDidChangeChatSessionItems: this._itemsChangedEmitter.event,
-					get items() { return items; },
+					get items() { return controllerItems; },
 					async refresh() { /* in-memory, no-op */ },
 				}));
 
@@ -400,6 +412,83 @@ class MockChatAgentContribution extends Disposable implements IWorkbenchContribu
 		}
 	}
 
+	private registerMockTerminalBackend(): void {
+		const terminalService = this.terminalService;
+		const backend = this.createMockTerminalBackend();
+		Registry.as<ITerminalBackendRegistry>(TerminalExtensions.Backend).registerTerminalBackend(backend);
+		terminalService.registerProcessSupport(true);
+		console.log('[Sessions Web Test] Registered mock terminal backend');
+	}
+
+	private createMockTerminalBackend(): ITerminalBackend {
+		return {
+			remoteAuthority: undefined,
+			isVirtualProcess: false,
+			onDidRequestDetach: Event.None,
+			attachToProcess: async () => { throw new Error('Not supported'); },
+			attachToRevivedProcess: async () => { throw new Error('Not supported'); },
+			listProcesses: async () => [],
+			getProfiles: async () => [],
+			getDefaultProfile: async () => undefined,
+			getDefaultSystemShell: async () => '/bin/mock-shell',
+			getShellEnvironment: async () => ({}),
+			setTerminalLayoutInfo: async () => { },
+			getTerminalLayoutInfo: async () => undefined,
+			reduceConnectionGraceTime: () => { },
+			requestDetachInstance: () => { },
+			acceptDetachInstanceReply: () => { },
+			persistTerminalState: () => { },
+			createProcess: async (_shellLaunchConfig: IShellLaunchConfig, _cwd: string | URI, _cols: number, _rows: number, _unicodeVersion: string, _env: IProcessEnvironment, _options: ITerminalProcessOptions, _shouldPersist: boolean) => {
+				const onProcessData = new Emitter<string>();
+				const onProcessReady = new Emitter<IProcessReadyEvent>();
+				const onProcessExit = new Emitter<number | undefined>();
+				const onDidChangeHasChildProcesses = new Emitter<boolean>();
+				const onDidChangeProperty = new Emitter<IProcessProperty<ProcessPropertyType>>();
+
+				// Resolve cwd from createProcess arg or shellLaunchConfig
+				const rawCwd = _cwd || _shellLaunchConfig.cwd;
+				const cwd = !rawCwd ? '/' : typeof rawCwd === 'string' ? rawCwd : rawCwd.path;
+				console.log(`[Sessions Web Test] Mock terminal createProcess cwd: '${cwd}' (raw _cwd: '${_cwd}', slc.cwd: '${_shellLaunchConfig.cwd}')`);
+
+				// Fire ready after a microtask so the terminal service can wire up listeners
+				setTimeout(() => {
+					onProcessReady.fire({ pid: 1, cwd, windowsPty: undefined });
+				}, 0);
+
+				return {
+					id: 0,
+					shouldPersist: false,
+					onProcessData: onProcessData.event,
+					onProcessReady: onProcessReady.event,
+					onDidChangeHasChildProcesses: onDidChangeHasChildProcesses.event,
+					onDidChangeProperty: onDidChangeProperty.event,
+					onProcessExit: onProcessExit.event,
+					start: async () => undefined,
+					shutdown: async () => { },
+					input: async () => { },
+					resize: () => { },
+					clearBuffer: () => { },
+					acknowledgeDataEvent: () => { },
+					setUnicodeVersion: async () => { },
+					getInitialCwd: async () => cwd,
+					getCwd: async () => cwd,
+					getLatency: async () => [],
+					processBinary: async () => { },
+					refreshProperty: async (property: ProcessPropertyType) => { throw new Error(`Not supported: ${property}`); },
+					updateProperty: async () => { },
+					clearUnrespondedRequest: () => { },
+				};
+			},
+			getWslPath: async (original: string, _direction: 'unix-to-win' | 'win-to-unix') => original,
+			getEnvironment: async () => ({}),
+			getPerformanceMarks: () => [],
+			onPtyHostUnresponsive: Event.None,
+			onPtyHostResponsive: Event.None,
+			onPtyHostRestart: Event.None,
+			onPtyHostConnected: Event.None,
+		} as unknown as ITerminalBackend;
+	}
+
 	private preseedFolder(): void {
 		const mockFolderUri = URI.from({ scheme: 'mock-fs', authority: 'mock-repo', path: '/mock-repo' }).toString();
 		this.storageService.store('agentSessions.lastPickedFolder', mockFolderUri, StorageScope.PROFILE, StorageTarget.MACHINE);