[pull] main from microsoft:main

.github/skills/vscode-dev-workbench/SKILL.md

@@ -21,12 +21,20 @@ If your paths differ, check `server/` in `vscode-dev` for the source root resolu
 
 ## Start the dev server
 
+**Critical:** Run `npm run dev` from the **`vscode-dev`** folder, NOT from `vscode`. The `vscode` repo has no `dev` script and will fail with `npm error Missing script: "dev"`. Terminal tools that simplify/strip leading `cd` into separate commands will silently keep the cwd of a previous terminal — always use an absolute `pushd` or verify with `pwd` before `npm run dev`.
+
 ```bash
-cd vscode-dev
-npm run dev   # runs watch + nodemon; serves https://127.0.0.1:3000
+cd /path/to/vscode-dev     # NOT /path/to/vscode
+npm run dev                # runs watch + nodemon; serves https://127.0.0.1:3000
 ```
 
-On first start you may see one crash like `Cannot find module './indexes'` — it's the watcher racing the first build. nodemon restarts automatically once `out/` finishes compiling.
+If you're driving this through an agent/terminal tool, prefer:
+
+```bash
+pushd /absolute/path/to/vscode-dev >/dev/null && pwd && npm run dev
+```
+
+On first start you may see one crash like `Cannot find module './indexes'` — it's the watcher racing the first build. nodemon restarts automatically once `out/` finishes compiling. The server is ready when `curl -sk -o /dev/null -w "%{http_code}" https://127.0.0.1:3000/` returns `200`.
 
 ## URLs
 
@@ -97,15 +105,19 @@ For a true mobile viewport, drive a standalone Playwright script with `devices['
 
 ## Testing the Agents window against a local mock agent host
 
+If the scenario touches the Agents window (`/agents` route), you almost always need the mock agent host running. Without it, the Agents window will sit on the sign-in / tunnel-discovery screen and block any real interaction. Start it **in addition to** the dev server — it's a second terminal, not a replacement.
+
 `vscode-dev` supports a `?mock-agent-host=ws://…` URL parameter that short-circuits tunnel discovery and wires the Agents window to a raw WebSocket. Pair it with the mock agent host binary from `microsoft/vscode`:
 
 ```bash
-cd vscode
+cd /path/to/vscode
 node out/vs/platform/agentHost/node/agentHostServerMain.js \
   --enable-mock-agent --quiet --without-connection-token --port 8765
 # Listens on ws://localhost:8765
 ```
 
+Prerequisite: `out/` in the `vscode` repo must be populated by the `VS Code - Build` task (or `npm run watch`). If `out/vs/platform/agentHost/node/agentHostServerMain.js` is missing, start that task first.
+
 `--enable-mock-agent` registers the `ScriptedMockAgent` from `src/vs/platform/agentHost/test/node/mockAgent.ts` with one pre-existing session. Seed additional sessions via the `VSCODE_AGENT_HOST_MOCK_SEED_SESSIONS` env var, using a comma-separated list of session URIs (for example, `VSCODE_AGENT_HOST_MOCK_SEED_SESSIONS=mock://pre-1,mock://pre-2`). Scripted prompts include `hello`, `use-tool`, `error`, `permission`, `write-file`, `run-safe-command`, `slow`, `client-tool`, `subagent`, etc. (see `mockAgent.ts` for the full list).
 
 Then open:

extensions/copilot/package.json

@@ -235,6 +235,27 @@
 					]
 				}
 			},
+			{
+				"name": "skill",
+				"toolReferenceName": "skill",
+				"displayName": "%copilot.tools.skill.name%",
+				"icon": "$(book)",
+				"userDescription": "%copilot.tools.skill.description%",
+				"modelDescription": "Invoke a skill to handle a user's request with specialized instructions and workflows.\n\nSkills are domain-specific capabilities discovered from SKILL.md files. When a user's task matches an available skill, call this tool to load and apply it. If the user types a slash command (e.g. \"/deploy\", \"/test\"), treat it as a skill invocation.\n\nUsage:\n- Pass the skill name only (no arguments).\n- Examples: skill: \"docx\", skill: \"deploy\", skill: \"fix-ci-failures\"\n\nRules:\n- Available skills appear in system-reminder messages earlier in the conversation.\n- BLOCKING: When a matching skill exists, you MUST call this tool before producing any other output about the task.\n- Never reference a skill without calling this tool.\n- Do not call this tool for a skill that is already active in the current turn (indicated by a <command-name> tag).\n- Do not use this tool for built-in commands such as /help or /clear.",
+				"when": "config.github.copilot.chat.skillTool.enabled",
+				"inputSchema": {
+					"type": "object",
+					"properties": {
+						"skill": {
+							"type": "string",
+							"description": "The skill name. E.g., \"commit\", \"review-pr\", or \"pdf\""
+						}
+					},
+					"required": [
+						"skill"
+					]
+				}
+			},
 			{
 				"name": "copilot_searchWorkspaceSymbols",
 				"toolReferenceName": "symbols",
@@ -1265,7 +1286,8 @@
 					"problems",
 					"readFile",
 					"viewImage",
-					"readNotebookCellOutput"
+					"readNotebookCellOutput",
+					"skill"
 				]
 			},
 			{
@@ -4411,6 +4433,15 @@
 							"experimental"
 						]
 					},
+					"github.copilot.chat.skillTool.enabled": {
+						"type": "boolean",
+						"default": false,
+						"markdownDescription": "%github.copilot.config.skill.enabled%",
+						"tags": [
+							"advanced",
+							"experimental"
+						]
+					},
 					"github.copilot.chat.executionSubagent.enabled": {
 						"type": "boolean",
 						"default": false,

extensions/copilot/package.nls.json

@@ -490,6 +490,9 @@
 	"copilot.tools.runSubagent.description": "Runs a task within an isolated subagent context. Enables efficient organization of tasks and context window management.",
 	"copilot.tools.searchSubagent.name": "Search Subagent",
 	"copilot.tools.searchSubagent.description": "Launch an iterative search-focused subagent to find relevant code in your workspace.",
+	"copilot.tools.skill.name": "Skill",
+	"copilot.tools.skill.description": "Execute a skill by name. Skills provide specialized capabilities, domain knowledge, and refined workflows.",
+	"github.copilot.config.skill.enabled": "Enable the skill tool in Copilot Chat. When enabled, skills are invoked via a dedicated skill tool instead of readFile.",
 	"github.copilot.config.searchSubagent.enabled": "Enable the search subagent tool for iterative code exploration in the workspace.",
 	"github.copilot.config.searchSubagent.useAgenticProxy": "Use the agentic proxy for the search subagent tool.",
 	"github.copilot.config.searchSubagent.model": "Model to use for the search subagent. When useAgenticProxy is enabled, defaults to 'vscode-agentic-search-router-a'. Otherwise defaults to the main agent model.",

extensions/copilot/src/extension/intents/node/agentIntent.ts

@@ -120,6 +120,9 @@ export const getAgentTools = async (accessor: ServicesAccessor, request: vscode.
 	const executionSubagentEnabled = configurationService.getExperimentBasedConfig(ConfigKey.Advanced.ExecutionSubagentToolEnabled, experimentationService);
 	allowTools[ToolName.ExecutionSubagent] = isGptOrAnthropic && executionSubagentEnabled;
 
+	const skillToolEnabled = configurationService.getExperimentBasedConfig(ConfigKey.Advanced.SkillToolEnabled, experimentationService);
+	allowTools[ToolName.Skill] = skillToolEnabled;
+
 	allowTools[CUSTOM_TOOL_SEARCH_NAME] = !!model.supportsToolSearch;
 
 	if (model.family.includes('grok-code')) {

extensions/copilot/src/extension/intents/node/toolCallingLoop.ts

@@ -383,12 +383,29 @@ export abstract class ToolCallingLoop<TOptions extends IToolCallingLoopOptions =
 			return undefined;
 		}
 
+		// If the model produced a substantive text response with no tool calls, treat it
+		// as a final summary and let the loop stop. Nudging in this case typically just
+		// wastes a turn — the model considers itself done. The user can always continue
+		// the conversation if it wasn't.
+		if (result.round.toolCalls.length === 0 && result.round.response.trim().length > 0) {
+			this._logService.info('[ToolCallingLoop] Autopilot: model produced a text-only response, treating as done');
+			return undefined;
+		}
+
 		// safety valve — only give up after exhausting all continuation attempts
 		if (this.autopilotIterationCount >= ToolCallingLoop.MAX_AUTOPILOT_ITERATIONS) {
 			this._logService.info(`[ToolCallingLoop] Autopilot: hit max iterations (${ToolCallingLoop.MAX_AUTOPILOT_ITERATIONS}), letting it stop`);
 			return undefined;
 		}
 
+		// If we already nudged once and the model still produced no tool calls, the model
+		// is effectively done — further nudges just waste tokens. Bail out and let the
+		// loop stop.
+		if (this.autopilotStopHookActive && result.round.toolCalls.length === 0) {
+			this._logService.info('[ToolCallingLoop] Autopilot: prior nudge produced no tool calls, stopping to avoid wasted requests');
+			return undefined;
+		}
+
 		this.autopilotIterationCount++;
 		return 'You have not yet marked the task as complete using the task_complete tool. ' +
 			'You must call task_complete when done — whether the task involved code changes, answering a question, or any other interaction.\n\n' +
@@ -900,7 +917,7 @@ export abstract class ToolCallingLoop<TOptions extends IToolCallingLoopOptions =
 				const permLevel = this.options.request.permissionLevel;
 				if (permLevel === 'autopilot' && this.options.toolCallLimit < 200) {
 					this.options.toolCallLimit = Math.min(Math.round(this.options.toolCallLimit * 3 / 2), 200);
-					this.showAutopilotProgress(outputStream, l10n.t('Extending tool call limit with Autopilot...'), l10n.t('Extended tool call limit with Autopilot'));
+					this.showAutopilotProgress(outputStream, l10n.t('Autopilot: extending tool call limit\u2026'), l10n.t('Autopilot extended tool call limit'));
 				} else {
 					lastResult = this.hitToolCallLimit(outputStream, lastResult);
 					break;
@@ -951,9 +968,9 @@ export abstract class ToolCallingLoop<TOptions extends IToolCallingLoopOptions =
 						this.autopilotRetryCount++;
 						this._logService.info(`[ToolCallingLoop] Auto-retrying on error (attempt ${this.autopilotRetryCount}/${ToolCallingLoop.MAX_AUTOPILOT_RETRIES}): ${result.response.type}`);
 						if (this.options.request.permissionLevel === 'autopilot') {
-							this.showAutopilotProgress(outputStream, l10n.t('Request failed, retrying with Autopilot...'), l10n.t('Request failed, retried with Autopilot'));
+							this.showAutopilotProgress(outputStream, l10n.t('Autopilot: recovering from a request error\u2026'), l10n.t('Autopilot recovered from a request error'));
 						} else {
-							this.showAutopilotProgress(outputStream, l10n.t('Request failed, retrying request...'), l10n.t('Request failed, retried request'));
+							this.showAutopilotProgress(outputStream, l10n.t('Recovering from a request error\u2026'), l10n.t('Recovered from a request error'));
 						}
 						await timeout(1000, token);
 						continue;
@@ -1003,7 +1020,7 @@ export abstract class ToolCallingLoop<TOptions extends IToolCallingLoopOptions =
 						const autopilotContinue = this.shouldAutopilotContinue(result);
 						if (autopilotContinue) {
 							this._logService.info(`[ToolCallingLoop] Autopilot internal stop hook: continuing because task may not be complete`);
-							this.showAutopilotProgress(outputStream, l10n.t('Continuing with Autopilot: Task not yet complete'), l10n.t('Continued with Autopilot: Task not yet complete'));
+							this.showAutopilotProgress(outputStream, l10n.t('Autopilot: verifying task is done\u2026'), l10n.t('Autopilot continued working'));
 							this.stopHookReason = autopilotContinue;
 							result.round.hookContext = formatHookContext([autopilotContinue]);
 							this.autopilotStopHookActive = true;

extensions/copilot/src/extension/intents/test/node/toolCallingLoopAutopilot.spec.ts

@@ -102,10 +102,10 @@ function createTestConversation(turnCount: number = 1): Conversation {
 	return new Conversation(generateUuid(), turns);
 }
 
-function createMockRound(toolCallNames: string[] = []): IToolCallRound {
+function createMockRound(toolCallNames: string[] = [], response: string = ''): IToolCallRound {
 	return {
 		id: generateUuid(),
-		response: 'test response',
+		response,
 		toolInputRetry: 0,
 		toolCalls: toolCallNames.map(name => ({
 			id: generateUuid(),
@@ -150,10 +150,11 @@ describe('ToolCallingLoop autopilot', () => {
 		vi.restoreAllMocks();
 	});
 
-	function createLoop(permissionLevel?: string): AutopilotTestToolCallingLoop {
+	function createLoop(permissionLevel?: string, requestOverrides: Partial<ChatRequest> = {}): AutopilotTestToolCallingLoop {
 		const conversation = createTestConversation(1);
 		const request = createMockChatRequest({
 			permissionLevel,
+			...requestOverrides,
 		} as Partial<ChatRequest>);
 		const loop = instantiationService.createInstance(
 			AutopilotTestToolCallingLoop,
@@ -196,15 +197,24 @@ describe('ToolCallingLoop autopilot', () => {
 			expect(msg).toBeUndefined();
 		});
 
-		it('should keep nudging even with autopilotStopHookActive set', () => {
+		it('should bail when prior nudge produced no tool calls', () => {
 			const loop = createLoop('autopilot');
 
 			// Simulate that we already nudged once and set the flag
 			loop.setAutopilotStopHookActive(true);
 
-			// Should still return a nudge — autopilotStopHookActive no longer causes early bail
+			// Should bail — the previous nudge produced no tool calls, so further nudges
+			// would just waste tokens (the model is effectively done).
 			const result = loop.testShouldAutopilotContinue(createMockSingleResult());
-			expect(result).toContain('task_complete');
+			expect(result).toBeUndefined();
+		});
+
+		it('should skip the nudge when the model returned a text-only response (no tool calls)', () => {
+			const loop = createLoop('autopilot');
+			const result = loop.testShouldAutopilotContinue(createMockSingleResult({
+				round: createMockRound([], 'Here is a summary of what I did.'),
+			}));
+			expect(result).toBeUndefined();
 		});
 
 		it('should allow another nudge after autopilotStopHookActive is reset', () => {

extensions/copilot/src/extension/prompts/node/agent/agentPrompt.tsx

@@ -525,6 +525,8 @@ class SkillAdherenceReminder extends PromptElement<SkillAdherenceReminderProps>
 	constructor(
 		props: SkillAdherenceReminderProps,
 		@ICustomInstructionsService private readonly customInstructionsService: ICustomInstructionsService,
+		@IConfigurationService private readonly configurationService: IConfigurationService,
+		@IExperimentationService private readonly experimentationService: IExperimentationService,
 	) {
 		super(props);
 	}
@@ -541,6 +543,14 @@ class SkillAdherenceReminder extends PromptElement<SkillAdherenceReminderProps>
 			return undefined;
 		}
 
+		const skillToolEnabled = this.configurationService.getExperimentBasedConfig(ConfigKey.Advanced.SkillToolEnabled, this.experimentationService);
+
+		if (skillToolEnabled) {
+			return <Tag name='additional_skills_reminder'>
+				Always check if any skills apply to the user's request. If so, use the {ToolName.Skill} tool to invoke the skill by name. Multiple skill files may be needed for a single request. These files contain best practices built from testing that are needed for high-quality outputs.<br />
+			</Tag>;
+		}
+
 		return <Tag name='additional_skills_reminder'>
 			Always check if any skills apply to the user's request. If so, use the {ToolName.ReadFile} tool to read the corresponding SKILL.md files. Multiple skill files may be needed for a single request. These files contain best practices built from testing that are needed for high-quality outputs.<br />
 		</Tag>;

extensions/copilot/src/extension/tools/common/skillTelemetry.ts

@@ -0,0 +1,54 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { ICustomInstructionsService, ISkillInfo } from '../../../platform/customInstructions/common/customInstructionsService';
+import { IExtensionsService } from '../../../platform/extensions/common/extensionsService';
+import { ITelemetryService } from '../../../platform/telemetry/common/telemetry';
+import { hash } from '../../../util/vs/base/common/hash';
+import { URI } from '../../../util/vs/base/common/uri';
+
+/**
+ * Sends `skillContentRead` telemetry for a skill invocation.
+ * Shared between the skill tool and the readFile tool to ensure consistent
+ * telemetry when skills are loaded through either path.
+ *
+ * TODO: Add pluginNameHash and pluginVersion properties once vscode core's
+ * extensionPromptFileProvider command exposes IAgentPluginService metadata.
+ */
+export function sendSkillContentReadTelemetry(
+	telemetryService: ITelemetryService,
+	customInstructionsService: ICustomInstructionsService,
+	extensionsService: IExtensionsService,
+	uri: URI,
+	skillInfo: ISkillInfo,
+	content: string,
+): void {
+	const extensionSkillInfo = customInstructionsService.getExtensionSkillInfo(uri);
+	const extensionId = extensionSkillInfo?.extensionId ?? '';
+	const extensionVersion = extensionId ? extensionsService.getExtension(extensionId)?.packageJSON?.version ?? '' : '';
+	const contentHash = content ? String(hash(content)) : '';
+
+	const plaintextProps = {
+		skillName: skillInfo.skillName,
+		skillPath: uri.toString(),
+		skillExtensionId: extensionId,
+		skillExtensionVersion: extensionVersion,
+		skillStorage: skillInfo.storage,
+		skillContentHash: contentHash,
+	};
+
+	telemetryService.sendGHTelemetryEvent('skillContentRead',
+		{
+			skillNameHash: String(hash(skillInfo.skillName)),
+			skillExtensionIdHash: extensionId ? String(hash(extensionId)) : '',
+			skillExtensionVersion: plaintextProps.skillExtensionVersion,
+			skillStorage: plaintextProps.skillStorage,
+			skillContentHash: contentHash,
+		}
+	);
+
+	telemetryService.sendEnhancedGHTelemetryEvent('skillContentRead', plaintextProps);
+	telemetryService.sendInternalMSFTTelemetryEvent('skillContentRead', plaintextProps);
+}

extensions/copilot/src/extension/tools/common/toolNames.ts

@@ -74,6 +74,7 @@ export enum ToolName {
 	ToolSearch = 'tool_search',
 	ResolveMemoryFileUri = 'resolve_memory_file_uri',
 	ExecutionSubagent = 'execution_subagent',
+	Skill = 'skill',
 	SessionStoreSql = 'session_store_sql',
 	CoreOpenBrowserPage = 'open_browser_page',
 	CoreClickElement = 'click_element',
@@ -266,6 +267,7 @@ export const toolCategories: Record<ToolName, ToolCategory> = {
 	[ToolName.Memory]: ToolCategory.VSCodeInteraction,
 	[ToolName.ToolSearch]: ToolCategory.Core,
 	[ToolName.ResolveMemoryFileUri]: ToolCategory.Core,
+	[ToolName.Skill]: ToolCategory.Core,
 	[ToolName.SessionStoreSql]: ToolCategory.Core,
 } as const;
 

extensions/copilot/src/extension/tools/node/allTools.ts

@@ -20,6 +20,7 @@ import './githubTextSearchTool';
 import './insertEditTool';
 import './installExtensionTool';
 import './listDirTool';
+import './skillTool';
 import './manageTodoListTool';
 import './memoryTool';
 import './multiReplaceStringTool';