Add Agent Host session configuration flow

src/vs/platform/actionWidget/browser/actionList.ts

@@ -40,6 +40,7 @@ export const previewSelectedActionCommand = 'previewSelectedCodeAction';
 export interface IActionListDelegate<T> {
 	onHide(didCancel?: boolean): void;
 	onSelect(action: T, preview?: boolean): void;
+	onFilter?(filter: string, cancellationToken: CancellationToken): Promise<readonly IActionListItem<T>[]>;
 	onHover?(action: T, cancellationToken: CancellationToken): Promise<{ canPreview: boolean } | void>;
 	onFocus?(action: T | undefined): void;
 }
@@ -488,6 +489,7 @@ export class ActionListWidget<T> extends Disposable {
 	private _hasLaidOut = false;
 	private readonly _filterInput: HTMLInputElement | undefined;
 	private readonly _filterContainer: HTMLElement | undefined;
+	private readonly _filterCts = this._register(new MutableDisposable<CancellationTokenSource>());
 
 	private readonly _onDidRequestLayout = this._register(new Emitter<void>());
 
@@ -622,7 +624,7 @@ export class ActionListWidget<T> extends Disposable {
 
 			this._register(dom.addDisposableListener(this._filterInput, 'input', () => {
 				this._filterText = this._filterInput!.value;
-				this._applyFilter();
+				this._applyOrUpdateFilter();
 			}));
 		}
 
@@ -659,7 +661,7 @@ export class ActionListWidget<T> extends Disposable {
 					this._filterInput.focus();
 					this._filterInput.value = e.key;
 					this._filterText = e.key;
-					this._applyFilter();
+					this._applyOrUpdateFilter();
 					e.preventDefault();
 					e.stopPropagation();
 				}
@@ -677,9 +679,28 @@ export class ActionListWidget<T> extends Disposable {
 		this._applyFilter();
 	}
 
-	private _applyFilter(): void {
-		const filterLower = this._filterText.toLowerCase();
-		const isFiltering = filterLower.length > 0;
+	private _applyOrUpdateFilter(): void {
+		if (!this._delegate.onFilter) {
+			this._applyFilter();
+			return;
+		}
+
+		const filterText = this._filterText;
+		this._filterCts.value?.cancel();
+		const cts = new CancellationTokenSource();
+		this._filterCts.value = cts;
+		this._delegate.onFilter(filterText, cts.token).then(items => {
+			if (cts.token.isCancellationRequested) {
+				return;
+			}
+			this._allMenuItems = [...items];
+			this._applyFilter(true);
+		}).catch(() => { /* best-effort */ });
+	}
+
+	private _applyFilter(skipTextFilter = false): void {
+		const filterLower = skipTextFilter ? '' : this._filterText.toLowerCase();
+		const isFiltering = !skipTextFilter && filterLower.length > 0;
 		const visible: IActionListItem<T>[] = [];
 
 		// Remember the focused item before splice
@@ -841,6 +862,8 @@ export class ActionListWidget<T> extends Disposable {
 	hide(didCancel?: boolean): void {
 		this._delegate.onHide(didCancel);
 		this.cts.cancel();
+		this._filterCts.value?.cancel();
+		this._filterCts.clear();
 		this._hover.clear();
 		this._hideSubmenu();
 	}
@@ -849,7 +872,7 @@ export class ActionListWidget<T> extends Disposable {
 		if (this._filterInput && this._filterText) {
 			this._filterInput.value = '';
 			this._filterText = '';
-			this._applyFilter();
+			this._applyOrUpdateFilter();
 			return true;
 		}
 		return false;

src/vs/platform/actionWidget/test/browser/actionList.test.ts

@@ -0,0 +1,109 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import assert from 'assert';
+import { DeferredPromise, timeout } from '../../../../base/common/async.js';
+import { CancellationToken } from '../../../../base/common/cancellation.js';
+import { ensureNoDisposablesAreLeakedInTestSuite } from '../../../../base/test/common/utils.js';
+import { runWithFakedTimers } from '../../../../base/test/common/timeTravelScheduler.js';
+import { IHoverService } from '../../../hover/browser/hover.js';
+import { NullHoverService } from '../../../hover/test/browser/nullHoverService.js';
+import { TestInstantiationService } from '../../../instantiation/test/common/instantiationServiceMock.js';
+import { MockKeybindingService } from '../../../keybinding/test/common/mockKeybindingService.js';
+import { IKeybindingService } from '../../../keybinding/common/keybinding.js';
+import { IOpenerService } from '../../../opener/common/opener.js';
+import { NullOpenerService } from '../../../opener/test/common/nullOpenerService.js';
+import { ActionListItemKind, ActionListWidget, IActionListItem } from '../../browser/actionList.js';
+
+interface ITestActionItem {
+	readonly id: string;
+}
+
+function action(id: string): IActionListItem<ITestActionItem> {
+	return { kind: ActionListItemKind.Action, label: id, item: { id } };
+}
+
+function createActionListWidget(disposables: ReturnType<typeof ensureNoDisposablesAreLeakedInTestSuite>, options: {
+	readonly onFilter: (filter: string, cancellationToken: CancellationToken) => Promise<readonly IActionListItem<ITestActionItem>[]>;
+}): ActionListWidget<ITestActionItem> {
+	const instantiationService = disposables.add(new TestInstantiationService());
+	instantiationService.set(IKeybindingService, new MockKeybindingService());
+	instantiationService.set(IHoverService, NullHoverService);
+	instantiationService.set(IOpenerService, NullOpenerService);
+
+	const widget = disposables.add(instantiationService.createInstance(
+		ActionListWidget<ITestActionItem>,
+		'testActionList',
+		false,
+		[action('initial')],
+		{
+			onHide: () => { },
+			onSelect: () => { },
+			onFilter: options.onFilter,
+		},
+		undefined,
+		{ showFilter: true },
+	));
+
+	if (widget.filterContainer) {
+		document.body.appendChild(widget.filterContainer);
+		disposables.add({ dispose: () => widget.filterContainer?.remove() });
+	}
+	document.body.appendChild(widget.domNode);
+	disposables.add({ dispose: () => widget.domNode.remove() });
+	widget.layout(200, 200);
+
+	return widget;
+}
+
+function typeFilter(widget: ActionListWidget<ITestActionItem>, value: string): void {
+	assert.ok(widget.filterInput);
+	widget.filterInput.value = value;
+	widget.filterInput.dispatchEvent(new Event('input'));
+}
+
+suite('ActionListWidget', () => {
+	const disposables = ensureNoDisposablesAreLeakedInTestSuite();
+
+	test('runs dynamic filter updates immediately', () => runWithFakedTimers({ useFakeTimers: true }, async () => {
+		const filters: string[] = [];
+		const widget = createActionListWidget(disposables, {
+			onFilter: async filter => {
+				filters.push(filter);
+				return [action(`server-${filter === 'ma' ? 'ranked' : filter}-result`)];
+			},
+		});
+
+		typeFilter(widget, 'm');
+		typeFilter(widget, 'ma');
+		assert.deepStrictEqual(filters, ['m', 'ma']);
+		await timeout(0);
+		assert.ok(widget.domNode.textContent?.includes('server-ranked-result'));
+	}));
+
+	test('ignores stale dynamic filter results', async () => {
+		const firstResult = new DeferredPromise<readonly IActionListItem<ITestActionItem>[]>();
+		const secondResult = new DeferredPromise<readonly IActionListItem<ITestActionItem>[]>();
+		const filters: string[] = [];
+		const widget = createActionListWidget(disposables, {
+			onFilter: filter => {
+				filters.push(filter);
+				return filter === 'm' ? firstResult.p : secondResult.p;
+			},
+		});
+
+		typeFilter(widget, 'm');
+		typeFilter(widget, 'ma');
+		assert.deepStrictEqual(filters, ['m', 'ma']);
+
+		firstResult.complete([action('ma-stale-result')]);
+		await timeout(0);
+		assert.ok(!widget.domNode.textContent?.includes('ma-stale-result'));
+
+		secondResult.complete([action('ma-fresh-result')]);
+		await timeout(0);
+		assert.ok(widget.domNode.textContent?.includes('ma-fresh-result'));
+	});
+});

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

@@ -12,7 +12,7 @@ import type { ISyncedCustomization } from './agentPluginManager.js';
 import { IProtectedResourceMetadata } from './state/protocol/state.js';
 import type { IActionEnvelope, INotification, ISessionAction, ITerminalAction } from './state/sessionActions.js';
 import type { IAgentSubscription } from './state/agentSubscription.js';
-import type { ICreateTerminalParams } from './state/protocol/commands.js';
+import type { ICreateTerminalParams, IResolveSessionConfigResult, ISessionConfigCompletionsResult } from './state/protocol/commands.js';
 import type { IResourceCopyParams, IResourceCopyResult, IResourceDeleteParams, IResourceDeleteResult, IResourceListResult, IResourceMoveParams, IResourceMoveResult, IResourceReadResult, IResourceWriteParams, IResourceWriteResult, IStateSnapshot } from './state/sessionProtocol.js';
 import { AttachmentType, ComponentToState, SessionStatus, StateComponents, type ICustomizationRef, type IPendingMessage, type IRootState, type ISessionInputAnswer, type ISessionInputRequest, type IToolCallResult, type PolicyState, type StringOrMarkdown, SessionInputResponseKind } from './state/sessionState.js';
 
@@ -99,10 +99,24 @@ export interface IAgentCreateSessionConfig {
 	readonly model?: string;
 	readonly session?: URI;
 	readonly workingDirectory?: URI;
+	readonly config?: Record<string, string>;
 	/** Fork from an existing session at a specific turn index. */
 	readonly fork?: { readonly session: URI; readonly turnIndex: number };
 }
 
+export const AgentHostSessionConfigBranchNameHintKey = 'branchNameHint';
+
+export interface IAgentResolveSessionConfigParams {
+	readonly provider?: AgentProvider;
+	readonly workingDirectory?: URI;
+	readonly config?: Record<string, string>;
+}
+
+export interface IAgentSessionConfigCompletionsParams extends IAgentResolveSessionConfigParams {
+	readonly property: string;
+	readonly query?: string;
+}
+
 /** Serializable attachment passed alongside a message to the agent host. */
 export interface IAgentAttachment {
 	readonly type: AttachmentType;
@@ -335,6 +349,12 @@ export interface IAgent {
 	/** Create a new session. Returns server-owned session metadata. */
 	createSession(config?: IAgentCreateSessionConfig): Promise<IAgentCreateSessionResult>;
 
+	/** Resolve the dynamic configuration schema for creating a session. */
+	resolveSessionConfig(params: IAgentResolveSessionConfigParams): Promise<IResolveSessionConfigResult>;
+
+	/** Return dynamic completions for a session configuration property. */
+	sessionConfigCompletions(params: IAgentSessionConfigCompletionsParams): Promise<ISessionConfigCompletionsResult>;
+
 	/** Send a user message into an existing session. */
 	sendMessage(session: URI, prompt: string, attachments?: IAgentAttachment[], turnId?: string): Promise<void>;
 
@@ -452,6 +472,12 @@ export interface IAgentService {
 	/** Create a new session. Returns the session URI. */
 	createSession(config?: IAgentCreateSessionConfig): Promise<URI>;
 
+	/** Resolve the dynamic configuration schema for creating a session. */
+	resolveSessionConfig(params: IAgentResolveSessionConfigParams): Promise<IResolveSessionConfigResult>;
+
+	/** Return dynamic completions for a session configuration property. */
+	sessionConfigCompletions(params: IAgentSessionConfigCompletionsParams): Promise<ISessionConfigCompletionsResult>;
+
 	/** Dispose a session in the agent host, freeing SDK resources. */
 	disposeSession(session: URI): Promise<void>;
 
@@ -557,6 +583,8 @@ export interface IAgentConnection {
 	authenticate(params: IAuthenticateParams): Promise<IAuthenticateResult>;
 	listSessions(): Promise<IAgentSessionMetadata[]>;
 	createSession(config?: IAgentCreateSessionConfig): Promise<URI>;
+	resolveSessionConfig(params: IAgentResolveSessionConfigParams): Promise<IResolveSessionConfigResult>;
+	sessionConfigCompletions(params: IAgentSessionConfigCompletionsParams): Promise<ISessionConfigCompletionsResult>;
 	disposeSession(session: URI): Promise<void>;
 
 	// ---- Terminal lifecycle -------------------------------------------------

src/vs/platform/agentHost/common/state/protocol/.ahp-version

@@ -1 +1 @@
-1f72258
+7c0c693

src/vs/platform/agentHost/common/state/protocol/action-origin.generated.ts

@@ -9,7 +9,7 @@
 // Generated from types/actions.ts — do not edit
 // Run `npm run generate` to regenerate.
 
-import { ActionType, type IStateAction, type IRootAgentsChangedAction, type IRootActiveSessionsChangedAction, type IRootTerminalsChangedAction, type ISessionReadyAction, type ISessionCreationFailedAction, type ISessionTurnStartedAction, type ISessionDeltaAction, type ISessionResponsePartAction, type ISessionToolCallStartAction, type ISessionToolCallDeltaAction, type ISessionToolCallReadyAction, type ISessionToolCallConfirmedAction, type ISessionToolCallCompleteAction, type ISessionToolCallResultConfirmedAction, type ISessionToolCallContentChangedAction, type ISessionTurnCompleteAction, type ISessionTurnCancelledAction, type ISessionErrorAction, type ISessionTitleChangedAction, type ISessionUsageAction, type ISessionReasoningAction, type ISessionModelChangedAction, type ISessionServerToolsChangedAction, type ISessionActiveClientChangedAction, type ISessionActiveClientToolsChangedAction, type ISessionPendingMessageSetAction, type ISessionPendingMessageRemovedAction, type ISessionQueuedMessagesReorderedAction, type ISessionInputRequestedAction, type ISessionInputAnswerChangedAction, type ISessionInputCompletedAction, type ISessionCustomizationsChangedAction, type ISessionCustomizationToggledAction, type ISessionTruncatedAction, type ISessionIsReadChangedAction, type ISessionIsDoneChangedAction, type ISessionDiffsChangedAction, type ITerminalDataAction, type ITerminalInputAction, type ITerminalResizedAction, type ITerminalClaimedAction, type ITerminalTitleChangedAction, type ITerminalCwdChangedAction, type ITerminalExitedAction, type ITerminalClearedAction } from './actions.js';
+import { ActionType, type IStateAction, type IRootAgentsChangedAction, type IRootActiveSessionsChangedAction, type IRootTerminalsChangedAction, type ISessionReadyAction, type ISessionCreationFailedAction, type ISessionTurnStartedAction, type ISessionDeltaAction, type ISessionResponsePartAction, type ISessionToolCallStartAction, type ISessionToolCallDeltaAction, type ISessionToolCallReadyAction, type ISessionToolCallConfirmedAction, type ISessionToolCallCompleteAction, type ISessionToolCallResultConfirmedAction, type ISessionToolCallContentChangedAction, type ISessionTurnCompleteAction, type ISessionTurnCancelledAction, type ISessionErrorAction, type ISessionTitleChangedAction, type ISessionUsageAction, type ISessionReasoningAction, type ISessionModelChangedAction, type ISessionServerToolsChangedAction, type ISessionActiveClientChangedAction, type ISessionActiveClientToolsChangedAction, type ISessionPendingMessageSetAction, type ISessionPendingMessageRemovedAction, type ISessionQueuedMessagesReorderedAction, type ISessionInputRequestedAction, type ISessionInputAnswerChangedAction, type ISessionInputCompletedAction, type ISessionCustomizationsChangedAction, type ISessionCustomizationToggledAction, type ISessionTruncatedAction, type ISessionIsReadChangedAction, type ISessionIsDoneChangedAction, type ISessionDiffsChangedAction, type ISessionConfigChangedAction, type ITerminalDataAction, type ITerminalInputAction, type ITerminalResizedAction, type ITerminalClaimedAction, type ITerminalTitleChangedAction, type ITerminalCwdChangedAction, type ITerminalExitedAction, type ITerminalClearedAction } from './actions.js';
 
 
 // ─── Root vs Session vs Terminal Action Unions ───────────────────────────────
@@ -57,6 +57,7 @@ export type ISessionAction =
 	| ISessionIsReadChangedAction
 	| ISessionIsDoneChangedAction
 	| ISessionDiffsChangedAction
+	| ISessionConfigChangedAction
 	;
 
 /** Union of session actions that clients may dispatch. */
@@ -79,6 +80,7 @@ export type IClientSessionAction =
 	| ISessionTruncatedAction
 	| ISessionIsReadChangedAction
 	| ISessionIsDoneChangedAction
+	| ISessionConfigChangedAction
 	;
 
 /** Union of session actions that only the server may produce. */
@@ -173,6 +175,7 @@ export const IS_CLIENT_DISPATCHABLE: { readonly [K in IStateAction['type']]: boo
 	[ActionType.SessionIsReadChanged]: true,
 	[ActionType.SessionIsDoneChanged]: true,
 	[ActionType.SessionDiffsChanged]: false,
+	[ActionType.SessionConfigChanged]: true,
 	[ActionType.TerminalData]: false,
 	[ActionType.TerminalInput]: true,
 	[ActionType.TerminalResized]: true,

src/vs/platform/agentHost/common/state/protocol/actions.ts

@@ -53,6 +53,7 @@ export const enum ActionType {
 	SessionIsReadChanged = 'session/isReadChanged',
 	SessionIsDoneChanged = 'session/isDoneChanged',
 	SessionDiffsChanged = 'session/diffsChanged',
+	SessionConfigChanged = 'session/configChanged',
 	RootTerminalsChanged = 'root/terminalsChanged',
 	TerminalData = 'terminal/data',
 	TerminalInput = 'terminal/input',
@@ -663,6 +664,27 @@ export interface ISessionCustomizationToggledAction {
 	enabled: boolean;
 }
 
+// ─── Config Actions ──────────────────────────────────────────────────────────
+
+/**
+ * Client changed a mutable config value mid-session.
+ *
+ * Only properties with `sessionMutable: true` in the config schema may be
+ * changed. The server validates and broadcasts the action; the reducer merges
+ * the new values into `state.config.values`.
+ *
+ * @category Session Actions
+ * @version 1
+ * @clientDispatchable
+ */
+export interface ISessionConfigChangedAction {
+	type: ActionType.SessionConfigChanged;
+	/** Session URI */
+	session: URI;
+	/** Updated config values (merged into existing config) */
+	config: Record<string, string>;
+}
+
 // ─── Truncation ──────────────────────────────────────────────────────────────
 
 /**
@@ -1006,6 +1028,7 @@ export type IStateAction =
 	| ISessionIsReadChangedAction
 	| ISessionIsDoneChangedAction
 	| ISessionDiffsChangedAction
+	| ISessionConfigChangedAction
 	| ITerminalDataAction
 	| ITerminalInputAction
 	| ITerminalResizedAction