feat: add support for Copilot user agents and related functionality

src/vs/workbench/contrib/chat/browser/chat.contribution.ts

@@ -53,7 +53,7 @@ import { ILanguageModelToolsService } from '../common/tools/languageModelToolsSe
 import { agentPluginDiscoveryRegistry, IAgentPluginService } from '../common/plugins/agentPluginService.js';
 import { ChatPromptFilesExtensionPointHandler } from '../common/promptSyntax/chatPromptFilesContribution.js';
 import { PromptsConfig } from '../common/promptSyntax/config/config.js';
-import { INSTRUCTIONS_DEFAULT_SOURCE_FOLDER, INSTRUCTION_FILE_EXTENSION, LEGACY_MODE_DEFAULT_SOURCE_FOLDER, LEGACY_MODE_FILE_EXTENSION, PROMPT_DEFAULT_SOURCE_FOLDER, PROMPT_FILE_EXTENSION, DEFAULT_SKILL_SOURCE_FOLDERS, AGENTS_SOURCE_FOLDER, AGENT_FILE_EXTENSION, SKILL_FILENAME, CLAUDE_AGENTS_SOURCE_FOLDER, DEFAULT_HOOK_FILE_PATHS, DEFAULT_INSTRUCTIONS_SOURCE_FOLDERS, PromptFileSource } from '../common/promptSyntax/config/promptFileLocations.js';
+import { INSTRUCTIONS_DEFAULT_SOURCE_FOLDER, INSTRUCTION_FILE_EXTENSION, LEGACY_MODE_DEFAULT_SOURCE_FOLDER, LEGACY_MODE_FILE_EXTENSION, PROMPT_DEFAULT_SOURCE_FOLDER, PROMPT_FILE_EXTENSION, DEFAULT_SKILL_SOURCE_FOLDERS, AGENTS_SOURCE_FOLDER, AGENT_FILE_EXTENSION, SKILL_FILENAME, CLAUDE_AGENTS_SOURCE_FOLDER, DEFAULT_HOOK_FILE_PATHS, DEFAULT_INSTRUCTIONS_SOURCE_FOLDERS, PromptFileSource, COPILOT_USER_AGENTS_SOURCE_FOLDER } from '../common/promptSyntax/config/promptFileLocations.js';
 import { PromptLanguageFeaturesProvider } from '../common/promptSyntax/promptFileContributions.js';
 import { AGENT_DOCUMENTATION_URL, INSTRUCTIONS_DOCUMENTATION_URL, PROMPT_DOCUMENTATION_URL, SKILL_DOCUMENTATION_URL, HOOK_DOCUMENTATION_URL, PromptsType } from '../common/promptSyntax/promptTypes.js';
 import { hookFileSchema, HOOK_SCHEMA_URI } from '../common/promptSyntax/hookSchema.js';
@@ -884,6 +884,7 @@ configurationRegistry.registerConfiguration({
 			default: {
 				[AGENTS_SOURCE_FOLDER]: true,
 				[CLAUDE_AGENTS_SOURCE_FOLDER]: true,
+				[COPILOT_USER_AGENTS_SOURCE_FOLDER]: true,
 			},
 			additionalProperties: { type: 'boolean' },
 			propertyNames: {

src/vs/workbench/contrib/chat/common/promptSyntax/config/promptFileLocations.ts

@@ -86,6 +86,11 @@ export const AGENTS_SOURCE_FOLDER = '.github/agents';
  */
 export const CLAUDE_AGENTS_SOURCE_FOLDER = '.claude/agents';
 
+/**
+ * Copilot user agents folder.
+ */
+export const COPILOT_USER_AGENTS_SOURCE_FOLDER = '~/.copilot/agents';
+
 /**
  * Claude rules folder.
  */
@@ -186,6 +191,7 @@ export const DEFAULT_AGENT_SOURCE_FOLDERS: readonly IPromptSourceFolder[] = [
 	{ path: AGENTS_SOURCE_FOLDER, source: PromptFileSource.GitHubWorkspace, storage: PromptsStorage.local },
 	{ path: CLAUDE_AGENTS_SOURCE_FOLDER, source: PromptFileSource.ClaudeWorkspace, storage: PromptsStorage.local },
 	{ path: '~/' + CLAUDE_AGENTS_SOURCE_FOLDER, source: PromptFileSource.ClaudePersonal, storage: PromptsStorage.user },
+	{ path: COPILOT_USER_AGENTS_SOURCE_FOLDER, source: PromptFileSource.CopilotPersonal, storage: PromptsStorage.user },
 ];
 
 /**
@@ -204,7 +210,7 @@ export const DEFAULT_HOOK_FILE_PATHS: readonly IPromptSourceFolder[] = [
  */
 function isInAgentsFolder(fileUri: URI): boolean {
 	const dir = dirname(fileUri.path);
-	return dir.endsWith('/' + AGENTS_SOURCE_FOLDER) || dir.endsWith('/' + CLAUDE_AGENTS_SOURCE_FOLDER);
+	return dir.endsWith('/' + AGENTS_SOURCE_FOLDER) || dir.endsWith('/' + CLAUDE_AGENTS_SOURCE_FOLDER) || isInCopilotAgentsFolder(fileUri);
 }
 
 /**
@@ -215,6 +221,14 @@ export function isInClaudeAgentsFolder(fileUri: URI): boolean {
 	return dir.endsWith('/' + CLAUDE_AGENTS_SOURCE_FOLDER);
 }
 
+/**
+ * Helper function to check if a file is directly in the ~/.copilot/agents/ folder.
+ */
+export function isInCopilotAgentsFolder(fileUri: URI): boolean {
+	const dir = dirname(fileUri.path);
+	return dir.endsWith(COPILOT_USER_AGENTS_SOURCE_FOLDER.substring(1));
+}
+
 /**
  * Helper function to check if a file is inside the .claude/rules/ folder (including subfolders).
  * Claude rules files (.md) in this folder are treated as instruction files.

src/vs/workbench/contrib/chat/common/promptSyntax/languageProviders/promptValidator.ts

@@ -23,10 +23,9 @@ import { ResourceMap } from '../../../../../../base/common/map.js';
 import { IFileService } from '../../../../../../platform/files/common/files.js';
 import { IPromptsService, Target } from '../service/promptsService.js';
 import { ILabelService } from '../../../../../../platform/label/common/label.js';
-import { AGENTS_SOURCE_FOLDER, CLAUDE_AGENTS_SOURCE_FOLDER, isInClaudeRulesFolder, LEGACY_MODE_FILE_EXTENSION } from '../config/promptFileLocations.js';
+import { AGENTS_SOURCE_FOLDER, isInClaudeAgentsFolder, isInClaudeRulesFolder, isInCopilotAgentsFolder, LEGACY_MODE_FILE_EXTENSION } from '../config/promptFileLocations.js';
 import { Lazy } from '../../../../../../base/common/lazy.js';
 import { CancellationToken } from '../../../../../../base/common/cancellation.js';
-import { dirname } from '../../../../../../base/common/resources.js';
 import { URI } from '../../../../../../base/common/uri.js';
 
 export const MARKERS_OWNER_ID = 'prompts-diagnostics-provider';
@@ -1023,10 +1022,12 @@ export function isVSCodeOrDefaultTarget(target: Target): boolean {
 export function getTarget(promptType: PromptsType, header: PromptHeader | URI): Target {
 	const uri = header instanceof URI ? header : header.uri;
 	if (promptType === PromptsType.agent) {
-		const parentDir = dirname(uri);
-		if (parentDir.path.endsWith(`/${CLAUDE_AGENTS_SOURCE_FOLDER}`)) {
+		if (isInClaudeAgentsFolder(uri)) {
 			return Target.Claude;
 		}
+		if (isInCopilotAgentsFolder(uri)) {
+			return Target.GitHubCopilot;
+		}
 		if (!(header instanceof URI)) {
 			const target = header.target;
 			if (target === Target.GitHubCopilot || target === Target.VSCode) {

src/vs/workbench/contrib/chat/test/common/promptSyntax/config/promptFileLocations.test.ts

@@ -48,6 +48,36 @@ suite('promptFileLocations', function () {
 			assert.strictEqual(getPromptFileType(uri), undefined);
 		});
 
+		test('.md files in .claude/agents/ subfolder should NOT be recognized as agent files', () => {
+			const uri = URI.file('/workspace/.claude/agents/subfolder/test.md');
+			assert.strictEqual(getPromptFileType(uri), undefined);
+		});
+
+		test('.md files in ~/.copilot/agents/ subfolder should NOT be recognized as agent files', () => {
+			const uri = URI.file('/home/user/.copilot/agents/subfolder/test.md');
+			assert.strictEqual(getPromptFileType(uri), undefined);
+		});
+
+		test('.md files in .claude/agents/ folder should be recognized as agent files', () => {
+			const uri = URI.file('/workspace/.claude/agents/demonstrate.md');
+			assert.strictEqual(getPromptFileType(uri), PromptsType.agent);
+		});
+
+		test('README.md in .claude/agents/ should NOT be recognized as agent file', () => {
+			const uri = URI.file('/workspace/.claude/agents/README.md');
+			assert.strictEqual(getPromptFileType(uri), undefined);
+		});
+
+		test('.md files in ~/.copilot/agents/ folder should be recognized as agent files', () => {
+			const uri = URI.file('/home/user/.copilot/agents/my-agent.md');
+			assert.strictEqual(getPromptFileType(uri), PromptsType.agent);
+		});
+
+		test('README.md in ~/.copilot/agents/ should NOT be recognized as agent file', () => {
+			const uri = URI.file('/home/user/.copilot/agents/README.md');
+			assert.strictEqual(getPromptFileType(uri), undefined);
+		});
+
 		test('.md files outside .github/agents/ should not be recognized as agent files', () => {
 			const uri = URI.file('/workspace/test/foo.md');
 			assert.strictEqual(getPromptFileType(uri), undefined);
@@ -130,6 +160,16 @@ suite('promptFileLocations', function () {
 			assert.strictEqual(getCleanPromptName(uri), 'demonstrate');
 		});
 
+		test('removes .md extension for files in .claude/agents/', () => {
+			const uri = URI.file('/workspace/.claude/agents/claude-agent.md');
+			assert.strictEqual(getCleanPromptName(uri), 'claude-agent');
+		});
+
+		test('removes .md extension for files in ~/.copilot/agents/', () => {
+			const uri = URI.file('/home/user/.copilot/agents/my-agent.md');
+			assert.strictEqual(getCleanPromptName(uri), 'my-agent');
+		});
+
 		test('README.md in .github/agents/ should keep .md extension', () => {
 			const uri = URI.file('/workspace/.github/agents/README.md');
 			assert.strictEqual(getCleanPromptName(uri), 'README.md');

src/vs/workbench/contrib/chat/test/common/promptSyntax/service/promptsService.test.ts

@@ -1177,6 +1177,56 @@ suite('PromptsService', () => {
 			);
 		});
 
+		test('copilot user agents from ~/.copilot/agents/ should have GitHubCopilot target', async () => {
+			const rootFolderName = 'copilot-user-agents';
+			const rootFolder = `/${rootFolderName}`;
+			const rootFolderUri = URI.file(rootFolder);
+
+			workspaceContextService.setWorkspace(testWorkspace(rootFolderUri));
+
+			await mockFiles(fileService, [
+				{
+					// Copilot user agent in ~/.copilot/agents/ (resolved from /home/user/.copilot/agents/)
+					path: '/home/user/.copilot/agents/copilot-user-agent.md',
+					contents: [
+						'---',
+						'description: \'Copilot user agent from home folder.\'',
+						'tools: [ read ]',
+						'---',
+						'I am a Copilot user agent.',
+					]
+				},
+			]);
+
+			const result = (await service.getCustomAgents(CancellationToken.None)).map(agent => ({ ...agent, uri: URI.from(agent.uri) }));
+			const expected: ICustomAgent[] = [
+				{
+					name: 'copilot-user-agent',
+					description: 'Copilot user agent from home folder.',
+					target: Target.GitHubCopilot,
+					tools: ['read'],
+					agentInstructions: {
+						content: 'I am a Copilot user agent.',
+						toolReferences: [],
+						metadata: undefined
+					},
+					handOffs: undefined,
+					model: undefined,
+					argumentHint: undefined,
+					visibility: { userInvocable: true, agentInvocable: true },
+					agents: undefined,
+					uri: URI.file('/home/user/.copilot/agents/copilot-user-agent.md'),
+					source: { storage: PromptsStorage.user }
+				},
+			];
+
+			assert.deepEqual(
+				result,
+				expected,
+				'Agents from ~/.copilot/agents/ must have Target.GitHubCopilot.',
+			);
+		});
+
 		test('agents with .md extension should be recognized, except README.md', async () => {
 			const rootFolderName = 'custom-agents-md-extension';
 			const rootFolder = `/${rootFolderName}`;