chat: make sendChatRequest extensionIdentifier parameter optional

.vscode/notebooks/my-work.github-issues

@@ -7,7 +7,7 @@
   {
     "kind": 2,
     "language": "github-issues",
-    "value": "// list of repos we work in\n$REPOS=repo:microsoft/lsprotocol repo:microsoft/monaco-editor repo:microsoft/vscode repo:microsoft/vscode-anycode repo:microsoft/vscode-autopep8 repo:microsoft/vscode-black-formatter repo:microsoft/vscode-copilot repo:microsoft/vscode-copilot-release repo:microsoft/vscode-dev repo:microsoft/vscode-dev-chrome-launcher repo:microsoft/vscode-emmet-helper repo:microsoft/vscode-extension-telemetry repo:microsoft/vscode-flake8 repo:microsoft/vscode-github-issue-notebooks repo:microsoft/vscode-hexeditor repo:microsoft/vscode-internalbacklog repo:microsoft/vscode-isort repo:microsoft/vscode-js-debug repo:microsoft/vscode-jupyter repo:microsoft/vscode-jupyter-internal repo:microsoft/vscode-l10n repo:microsoft/vscode-livepreview repo:microsoft/vscode-markdown-languageservice repo:microsoft/vscode-markdown-tm-grammar repo:microsoft/vscode-mypy repo:microsoft/vscode-pull-request-github repo:microsoft/vscode-pylint repo:microsoft/vscode-python repo:microsoft/vscode-python-debugger repo:microsoft/vscode-python-tools-extension-template repo:microsoft/vscode-references-view repo:microsoft/vscode-remote-release repo:microsoft/vscode-remote-repositories-github repo:microsoft/vscode-remote-tunnels repo:microsoft/vscode-remotehub repo:microsoft/vscode-settings-sync-server repo:microsoft/vscode-unpkg repo:microsoft/vscode-vsce repo:microsoft/vscode-copilot-issues repo:microsoft/vscode-extension-samples\n\n// current milestone name\n$MILESTONE=milestone:\"February 2026\"\n"
+    "value": "// list of repos we work in\n$REPOS=repo:microsoft/lsprotocol repo:microsoft/monaco-editor repo:microsoft/vscode repo:microsoft/vscode-anycode repo:microsoft/vscode-autopep8 repo:microsoft/vscode-black-formatter repo:microsoft/vscode-copilot repo:microsoft/vscode-copilot-release repo:microsoft/vscode-dev repo:microsoft/vscode-dev-chrome-launcher repo:microsoft/vscode-emmet-helper repo:microsoft/vscode-extension-telemetry repo:microsoft/vscode-flake8 repo:microsoft/vscode-github-issue-notebooks repo:microsoft/vscode-hexeditor repo:microsoft/vscode-internalbacklog repo:microsoft/vscode-isort repo:microsoft/vscode-js-debug repo:microsoft/vscode-jupyter repo:microsoft/vscode-jupyter-internal repo:microsoft/vscode-l10n repo:microsoft/vscode-livepreview repo:microsoft/vscode-markdown-languageservice repo:microsoft/vscode-markdown-tm-grammar repo:microsoft/vscode-mypy repo:microsoft/vscode-pull-request-github repo:microsoft/vscode-pylint repo:microsoft/vscode-python repo:microsoft/vscode-python-debugger repo:microsoft/vscode-python-tools-extension-template repo:microsoft/vscode-references-view repo:microsoft/vscode-remote-release repo:microsoft/vscode-remote-repositories-github repo:microsoft/vscode-remote-tunnels repo:microsoft/vscode-remotehub repo:microsoft/vscode-settings-sync-server repo:microsoft/vscode-unpkg repo:microsoft/vscode-vsce repo:microsoft/vscode-copilot-issues repo:microsoft/vscode-extension-samples\n\n// current milestone name\n$MILESTONE=milestone:\"March 2026\"\n"
   },
   {
     "kind": 1,

src/vs/workbench/api/common/extHost.protocol.ts

@@ -1368,7 +1368,7 @@ export interface MainThreadLanguageModelsShape extends IDisposable {
 export interface ExtHostLanguageModelsShape {
 	$provideLanguageModelChatInfo(vendor: string, options: ILanguageModelChatInfoOptions, token: CancellationToken): Promise<ILanguageModelChatMetadataAndIdentifier[]>;
 	$updateModelAccesslist(data: { from: ExtensionIdentifier; to: ExtensionIdentifier; enabled: boolean }[]): void;
-	$startChatRequest(modelId: string, requestId: number, from: ExtensionIdentifier, messages: SerializableObjectWithBuffers<IChatMessage[]>, options: { [name: string]: any }, token: CancellationToken): Promise<void>;
+	$startChatRequest(modelId: string, requestId: number, from: ExtensionIdentifier | undefined, messages: SerializableObjectWithBuffers<IChatMessage[]>, options: { [name: string]: any }, token: CancellationToken): Promise<void>;
 	$acceptResponsePart(requestId: number, chunk: SerializableObjectWithBuffers<IChatResponsePart | IChatResponsePart[]>): Promise<void>;
 	$acceptResponseDone(requestId: number, error: SerializedError | undefined): Promise<void>;
 	$provideTokenLength(modelId: string, value: string | IChatMessage, token: CancellationToken): Promise<number>;

src/vs/workbench/api/common/extHostLanguageModels.ts

@@ -258,7 +258,7 @@ export class ExtHostLanguageModels implements ExtHostLanguageModelsShape {
 		return modelMetadataAndIdentifier;
 	}
 
-	async $startChatRequest(modelId: string, requestId: number, from: ExtensionIdentifier, messages: SerializableObjectWithBuffers<IChatMessage[]>, options: vscode.LanguageModelChatRequestOptions, token: CancellationToken): Promise<void> {
+	async $startChatRequest(modelId: string, requestId: number, from: ExtensionIdentifier | undefined, messages: SerializableObjectWithBuffers<IChatMessage[]>, options: vscode.LanguageModelChatRequestOptions, token: CancellationToken): Promise<void> {
 		const knownModel = this._localModels.get(modelId);
 		if (!knownModel) {
 			throw new Error('Model not found');
@@ -319,7 +319,8 @@ export class ExtHostLanguageModels implements ExtHostLanguageModelsShape {
 			value = data.provider.provideLanguageModelChatResponse(
 				knownModel.info,
 				messages.value.map(typeConvert.LanguageModelChatMessage2.to),
-				{ ...options, modelOptions: options.modelOptions ?? {}, requestInitiator: ExtensionIdentifier.toKey(from), toolMode: options.toolMode ?? extHostTypes.LanguageModelChatToolMode.Auto },
+				// todo@connor4312: move `core` -> `undefined` after 1.111 Insiders is out
+				{ ...options, modelOptions: options.modelOptions ?? {}, requestInitiator: from ? ExtensionIdentifier.toKey(from) : 'core', toolMode: options.toolMode ?? extHostTypes.LanguageModelChatToolMode.Auto },
 				progress,
 				token
 			);

src/vs/workbench/contrib/chat/browser/chatEditing/chatEditingExplanationModelManager.ts

@@ -14,7 +14,6 @@ import { DetailedLineRangeMapping, LineRangeMapping } from '../../../../../edito
 import { createDecorator } from '../../../../../platform/instantiation/common/instantiation.js';
 import { InstantiationType, registerSingleton } from '../../../../../platform/instantiation/common/extensions.js';
 import { ChatMessageRole, ILanguageModelsService } from '../../common/languageModels.js';
-import { ExtensionIdentifier } from '../../../../../platform/extensions/common/extensions.js';
 import * as nls from '../../../../../nls.js';
 
 /**
@@ -284,7 +283,7 @@ Example response format:
 
 			const response = await this._languageModelsService.sendChatRequest(
 				models[0],
-				new ExtensionIdentifier('core'),
+				undefined,
 				[{ role: ChatMessageRole.User, content: [{ type: 'text', value: prompt }] }],
 				{},
 				cancellationToken

src/vs/workbench/contrib/chat/browser/widget/chatContentParts/chatThinkingContentPart.ts

@@ -32,7 +32,6 @@ import { autorun } from '../../../../../../base/common/observable.js';
 import { CancellationTokenSource } from '../../../../../../base/common/cancellation.js';
 import { IChatMarkdownAnchorService } from './chatMarkdownAnchorService.js';
 import { ChatMessageRole, ILanguageModelsService } from '../../../common/languageModels.js';
-import { ExtensionIdentifier } from '../../../../../../platform/extensions/common/extensions.js';
 import './media/chatThinkingContent.css';
 import { IHoverService } from '../../../../../../platform/hover/browser/hover.js';
 
@@ -958,7 +957,7 @@ ${this.hookCount > 0 ? `EXAMPLES WITH BLOCKED CONTENT (from hooks):
 
 			const response = await this.languageModelsService.sendChatRequest(
 				models[0],
-				new ExtensionIdentifier('core'),
+				undefined,
 				[{ role: ChatMessageRole.User, content: [{ type: 'text', value: prompt }] }],
 				{},
 				cts.token

src/vs/workbench/contrib/chat/browser/widget/chatQuestionCarouselAutoReply.ts

@@ -13,7 +13,6 @@ import { hasKey } from '../../../../../base/common/types.js';
 import { localize } from '../../../../../nls.js';
 import { IConfigurationService } from '../../../../../platform/configuration/common/configuration.js';
 import { IDialogService } from '../../../../../platform/dialogs/common/dialogs.js';
-import { ExtensionIdentifier } from '../../../../../platform/extensions/common/extensions.js';
 import { ILogService } from '../../../../../platform/log/common/log.js';
 import { IStorageService, StorageScope, StorageTarget } from '../../../../../platform/storage/common/storage.js';
 import { IChatQuestion, IChatQuestionCarousel } from '../../common/chatService/chatService.js';
@@ -191,7 +190,7 @@ export class ChatQuestionCarouselAutoReply extends Disposable {
 		const prompt = this.buildPrompt(carousel, requestMessageText, false);
 		const response = await this.languageModelsService.sendChatRequest(
 			modelId,
-			new ExtensionIdentifier('core'),
+			undefined,
 			[{ role: ChatMessageRole.User, content: [{ type: 'text', value: prompt }] }],
 			{},
 			token,
@@ -205,7 +204,7 @@ export class ChatQuestionCarouselAutoReply extends Disposable {
 		const retryPrompt = this.buildPrompt(carousel, requestMessageText, true);
 		const retryResponse = await this.languageModelsService.sendChatRequest(
 			modelId,
-			new ExtensionIdentifier('core'),
+			undefined,
 			[{ role: ChatMessageRole.User, content: [{ type: 'text', value: retryPrompt }] }],
 			{},
 			token,

src/vs/workbench/contrib/chat/common/languageModels.ts

@@ -263,13 +263,13 @@ export async function getTextResponseFromStream(response: ILanguageModelChatResp
 export interface ILanguageModelChatProvider {
 	readonly onDidChange: Event<void>;
 	provideLanguageModelChatInfo(options: ILanguageModelChatInfoOptions, token: CancellationToken): Promise<ILanguageModelChatMetadataAndIdentifier[]>;
-	sendChatRequest(modelId: string, messages: IChatMessage[], from: ExtensionIdentifier, options: { [name: string]: unknown }, token: CancellationToken): Promise<ILanguageModelChatResponse>;
+	sendChatRequest(modelId: string, messages: IChatMessage[], from: ExtensionIdentifier | undefined, options: { [name: string]: unknown }, token: CancellationToken): Promise<ILanguageModelChatResponse>;
 	provideTokenCount(modelId: string, message: string | IChatMessage, token: CancellationToken): Promise<number>;
 }
 
 export interface ILanguageModelChat {
 	metadata: ILanguageModelChatMetadata;
-	sendChatRequest(messages: IChatMessage[], from: ExtensionIdentifier, options: { [name: string]: unknown }, token: CancellationToken): Promise<ILanguageModelChatResponse>;
+	sendChatRequest(messages: IChatMessage[], from: ExtensionIdentifier | undefined, options: { [name: string]: unknown }, token: CancellationToken): Promise<ILanguageModelChatResponse>;
 	provideTokenCount(message: string | IChatMessage, token: CancellationToken): Promise<number>;
 }
 
@@ -355,7 +355,7 @@ export interface ILanguageModelsService {
 	deltaLanguageModelChatProviderDescriptors(added: IUserFriendlyLanguageModel[], removed: IUserFriendlyLanguageModel[]): void;
 
 	// eslint-disable-next-line @typescript-eslint/no-explicit-any
-	sendChatRequest(modelId: string, from: ExtensionIdentifier, messages: IChatMessage[], options: { [name: string]: any }, token: CancellationToken): Promise<ILanguageModelChatResponse>;
+	sendChatRequest(modelId: string, from: ExtensionIdentifier | undefined, messages: IChatMessage[], options: { [name: string]: any }, token: CancellationToken): Promise<ILanguageModelChatResponse>;
 
 	computeTokenLength(modelId: string, message: string | IChatMessage, token: CancellationToken): Promise<number>;
 
@@ -927,7 +927,7 @@ export class LanguageModelsService implements ILanguageModelsService {
 	}
 
 	// eslint-disable-next-line @typescript-eslint/no-explicit-any
-	async sendChatRequest(modelId: string, from: ExtensionIdentifier, messages: IChatMessage[], options: { [name: string]: any }, token: CancellationToken): Promise<ILanguageModelChatResponse> {
+	async sendChatRequest(modelId: string, from: ExtensionIdentifier | undefined, messages: IChatMessage[], options: { [name: string]: any }, token: CancellationToken): Promise<ILanguageModelChatResponse> {
 		const provider = this._providers.get(this._modelCache.get(modelId)?.vendor || '');
 		if (!provider) {
 			throw new Error(`Chat provider for model ${modelId} is not registered.`);

src/vs/workbench/contrib/chat/test/common/languageModels.test.ts

@@ -160,7 +160,7 @@ suite('LanguageModels', function () {
 				}));
 				return modelMetadataAndIdentifier;
 			},
-			sendChatRequest: async (modelId: string, messages: IChatMessage[], _from: ExtensionIdentifier, _options: { [name: string]: any }, token: CancellationToken) => {
+			sendChatRequest: async (modelId: string, messages: IChatMessage[], _from: ExtensionIdentifier | undefined, _options: { [name: string]: any }, token: CancellationToken) => {
 				// const message = messages.at(-1);
 
 				const defer = new DeferredPromise();

src/vs/workbench/contrib/chat/test/common/languageModels.ts

@@ -67,7 +67,7 @@ export class NullLanguageModelsService implements ILanguageModelsService {
 	}
 
 	// eslint-disable-next-line @typescript-eslint/no-explicit-any
-	sendChatRequest(identifier: string, from: ExtensionIdentifier, messages: IChatMessage[], options: { [name: string]: any }, token: CancellationToken): Promise<ILanguageModelChatResponse> {
+	sendChatRequest(identifier: string, from: ExtensionIdentifier | undefined, messages: IChatMessage[], options: { [name: string]: any }, token: CancellationToken): Promise<ILanguageModelChatResponse> {
 		throw new Error('Method not implemented.');
 	}
 

src/vs/workbench/contrib/mcp/common/mcpSamplingService.ts

@@ -15,7 +15,6 @@ import { localize } from '../../../../nls.js';
 import { ICommandService } from '../../../../platform/commands/common/commands.js';
 import { ConfigurationTarget, getConfigValueInTarget, IConfigurationService } from '../../../../platform/configuration/common/configuration.js';
 import { IDialogService } from '../../../../platform/dialogs/common/dialogs.js';
-import { ExtensionIdentifier } from '../../../../platform/extensions/common/extensions.js';
 import { IInstantiationService } from '../../../../platform/instantiation/common/instantiation.js';
 import { INotificationService, Severity } from '../../../../platform/notification/common/notification.js';
 import { ChatAgentLocation, ChatConfiguration } from '../../chat/common/constants.js';
@@ -81,7 +80,7 @@ export class McpSamplingService extends Disposable implements IMcpSamplingServic
 
 		const model = await this._modelSequencer.queue(() => this._getMatchingModel(opts));
 		// todo@connor4312: nullExtensionDescription.identifier -> undefined with API update
-		const response = await this._languageModelsService.sendChatRequest(model, new ExtensionIdentifier('core'), messages, {}, token);
+		const response = await this._languageModelsService.sendChatRequest(model, undefined, messages, {}, token);
 
 		let responseText = '';
 

src/vs/workbench/contrib/terminalContrib/chatAgentTools/browser/tools/monitoring/outputMonitor.ts

@@ -13,7 +13,6 @@ import { Disposable, MutableDisposable, type IDisposable } from '../../../../../
 import { isObject, isString } from '../../../../../../../base/common/types.js';
 import { URI } from '../../../../../../../base/common/uri.js';
 import { localize } from '../../../../../../../nls.js';
-import { ExtensionIdentifier } from '../../../../../../../platform/extensions/common/extensions.js';
 import { IChatWidgetService } from '../../../../../chat/browser/chat.js';
 import { ChatElicitationRequestPart } from '../../../../../chat/common/model/chatProgressTypes/chatElicitationRequestPart.js';
 import { ChatModel } from '../../../../../chat/common/model/chatModel.js';
@@ -473,7 +472,7 @@ export class OutputMonitor extends Disposable implements IOutputMonitor {
 
 		const response = await this._languageModelsService.sendChatRequest(
 			model,
-			new ExtensionIdentifier('core'),
+			undefined,
 			[{ role: ChatMessageRole.User, content: [{ type: 'text', value: `Evaluate this terminal output to determine if there were errors. If there are errors, return them. Otherwise, return undefined: ${buffer}.` }] }],
 			{},
 			token
@@ -546,7 +545,7 @@ export class OutputMonitor extends Disposable implements IOutputMonitor {
 			${lastLines}
 			`;
 
-		const response = await this._languageModelsService.sendChatRequest(model, new ExtensionIdentifier('core'), [{ role: ChatMessageRole.User, content: [{ type: 'text', value: promptText }] }], {}, token);
+		const response = await this._languageModelsService.sendChatRequest(model, undefined, [{ role: ChatMessageRole.User, content: [{ type: 'text', value: promptText }] }], {}, token);
 		const responseText = await getTextResponseFromStream(response);
 		try {
 			const match = responseText.match(/\{[\s\S]*\}/);
@@ -652,7 +651,7 @@ export class OutputMonitor extends Disposable implements IOutputMonitor {
 		if (model) {
 			try {
 				const promptText = `Given the following confirmation prompt and options from a terminal output, which option is the default?\nPrompt: "${prompt}"\nOptions: ${JSON.stringify(options)}\nRespond with only the option string.`;
-				const response = await this._languageModelsService.sendChatRequest(model, new ExtensionIdentifier('core'), [
+				const response = await this._languageModelsService.sendChatRequest(model, undefined, [
 					{ role: ChatMessageRole.User, content: [{ type: 'text', value: promptText }] }
 				], {}, token);
 

src/vscode-dts/vscode.proposed.chatProvider.d.ts

@@ -13,7 +13,8 @@ declare module 'vscode' {
 	export interface ProvideLanguageModelChatResponseOptions {
 
 		/**
-		 * What extension initiated the request to the language model
+		 * What extension initiated the request to the language model, or
+		 * `undefined` if the request was initiated by other functionality in the editor.
 		 */
 		readonly requestInitiator: string;
 	}