feat: wire hooks through CopilotCLI customization provider (#4952)

* feat: wire hooks through CopilotCLI customization provider

- Mirror updated chatPromptFiles d.ts with ChatHookProvider
- Add hooks/onDidChangeHooks to IChatPromptFileService interface
- Wire vscode.chat.hooks in ChatPromptFileService implementation
- Add Hook to CopilotCLI provider supportedTypes (unhides section)
- Add getHookItems() to CopilotCLI provider
- Subscribe to onDidChangeHooks for provider invalidation
- Fix all test mocks for new interface member

* chore: update vscodeCommit pointer via vscode-dts:update

* chore: remove backward compat guards for hooks API

---------

Co-authored-by: Justin Chen <54879025+justschen@users.noreply.github.com>

Author: joshspicer

package.json

@@ -6400,5 +6400,5 @@
 		"node-gyp": "npm:node-gyp@10.3.1",
 		"zod": "3.25.76"
 	},
-	"vscodeCommit": "f540be8c1abf14ef594d42dd3a99c50f48732a7b"
+	"vscodeCommit": "d0c21ae98319ccc4f796b6557b945faa9b72a3af"
 }

src/extension/chatSessions/common/chatPromptFileService.ts

@@ -50,4 +50,16 @@ export interface IChatPromptFileService extends IDisposable {
 	 * from all sources (workspace, user, and extension-provided).
 	 */
 	readonly skills: readonly ChatResource[];
+
+	/**
+	 * An event that fires when the list of {@link hooks hooks} changes.
+	 */
+	readonly onDidChangeHooks: Event<void>;
+
+	/**
+	 * The list of currently available hook configuration files.
+	 * These are JSON files that define lifecycle hooks from all sources
+	 * (workspace, user, and extension-provided).
+	 */
+	readonly hooks: readonly ChatResource[];
 }

src/extension/chatSessions/copilotcli/node/test/copilotCLISkills.spec.ts

@@ -34,10 +34,12 @@ class TestChatPromptFileService extends Disposable implements IChatPromptFileSer
 	readonly onDidChangeCustomAgents: Event<void> = Event.None;
 	readonly onDidChangeInstructions: Event<void> = Event.None;
 	readonly onDidChangeSkills: Event<void> = Event.None;
+	readonly onDidChangeHooks: Event<void> = Event.None;
 	readonly customAgents: readonly ChatResource[] = [];
 	readonly customAgentPromptFiles: readonly ParsedPromptFile[] = [];
 	readonly instructions: readonly ChatResource[] = [];
 	skills: readonly ChatResource[] = [];
+	readonly hooks: readonly ChatResource[] = [];
 }
 
 function createWorkspaceService(folders: URI[] = [URI.file('/workspace')]): IWorkspaceService {

src/extension/chatSessions/copilotcli/node/test/copilotCliAgents.spec.ts

@@ -49,9 +49,11 @@ class TestChatPromptFileService extends Disposable implements IChatPromptFileSer
 	readonly onDidChangeCustomAgents: Event<void> = this._onDidChangeCustomAgents.event;
 	readonly onDidChangeInstructions: Event<void> = Event.None;
 	readonly onDidChangeSkills: Event<void> = Event.None;
+	readonly onDidChangeHooks: Event<void> = Event.None;
 	readonly customAgents: readonly import('vscode').ChatResource[] = [];
 	readonly instructions: readonly import('vscode').ChatResource[] = [];
 	readonly skills: readonly import('vscode').ChatResource[] = [];
+	readonly hooks: readonly import('vscode').ChatResource[] = [];
 
 	constructor(private _customAgentPromptFiles: ParsedPromptFile[] = []) {
 		super();

src/extension/chatSessions/copilotcli/vscode-node/test/testHelpers.ts

@@ -237,9 +237,11 @@ export class MockChatPromptFileService extends Disposable implements IChatPrompt
 	customAgents: ChatResource[] = [];
 	instructions: ChatResource[] = [];
 	skills: ChatResource[] = [];
+	hooks: ChatResource[] = [];
 	private readonly _onDidChangeCustomAgents = this._register(new Emitter<void>());
 	private readonly _onDidChangeInstructions = this._register(new Emitter<void>());
 	private readonly _onDidChangeSkills = this._register(new Emitter<void>());
+	private readonly _onDidChangeHooks = this._register(new Emitter<void>());
 
 	get onDidChangeCustomAgents() {
 		return this._onDidChangeCustomAgents.event;
@@ -252,6 +254,10 @@ export class MockChatPromptFileService extends Disposable implements IChatPrompt
 	get onDidChangeSkills() {
 		return this._onDidChangeSkills.event;
 	}
+
+	get onDidChangeHooks() {
+		return this._onDidChangeHooks.event;
+	}
 	get customAgentPromptFiles() {
 		return [];
 	}

src/extension/chatSessions/vscode-node/chatPromptFileService.ts

@@ -22,6 +22,8 @@ export class ChatPromptFileService extends Disposable implements IChatPromptFile
 	readonly onDidChangeInstructions: Event<void> = this._onDidChangeInstructions.event;
 	private readonly _onDidChangeSkills = this._register(new Emitter<void>());
 	readonly onDidChangeSkills: Event<void> = this._onDidChangeSkills.event;
+	private readonly _onDidChangeHooks = this._register(new Emitter<void>());
+	readonly onDidChangeHooks: Event<void> = this._onDidChangeHooks.event;
 
 	private _customAgents: ParsedPromptFile[] = [];
 	private refreshCts: CancellationTokenSource | undefined;
@@ -43,6 +45,10 @@ export class ChatPromptFileService extends Disposable implements IChatPromptFile
 		this._register(vscode.chat.onDidChangeSkills(() => {
 			this._onDidChangeSkills.fire();
 		}));
+
+		this._register(vscode.chat.onDidChangeHooks(() => {
+			this._onDidChangeHooks.fire();
+		}));
 		this.triggerRefreshCustomAgents();
 	}
 
@@ -62,6 +68,10 @@ export class ChatPromptFileService extends Disposable implements IChatPromptFile
 		return vscode.chat.skills;
 	}
 
+	get hooks(): readonly vscode.ChatResource[] {
+		return vscode.chat.hooks;
+	}
+
 	override dispose(): void {
 		this.refreshCts?.dispose(true);
 		this.refreshCts = undefined;

src/extension/chatSessions/vscode-node/copilotCLICustomizationProvider.ts

@@ -25,6 +25,7 @@ export class CopilotCLICustomizationProvider extends Disposable implements vscod
 				vscode.ChatSessionCustomizationType.Agent,
 				vscode.ChatSessionCustomizationType.Skill,
 				vscode.ChatSessionCustomizationType.Instructions,
+				vscode.ChatSessionCustomizationType.Hook,
 			],
 		};
 	}
@@ -39,19 +40,22 @@ export class CopilotCLICustomizationProvider extends Disposable implements vscod
 		this._register(this.chatPromptFileService.onDidChangeCustomAgents(() => this._onDidChange.fire()));
 		this._register(this.chatPromptFileService.onDidChangeInstructions(() => this._onDidChange.fire()));
 		this._register(this.chatPromptFileService.onDidChangeSkills(() => this._onDidChange.fire()));
+		this._register(this.chatPromptFileService.onDidChangeHooks(() => this._onDidChange.fire()));
 		this._register(this.copilotCLIAgents.onDidChangeAgents(() => this._onDidChange.fire()));
 	}
 
 	async provideChatSessionCustomizations(_token: vscode.CancellationToken): Promise<vscode.ChatSessionCustomizationItem[]> {
 		const agents = await this.getAgentItems();
 		const instructions = this.getInstructionItems();
 		const skills = this.getSkillItems();
+		const hooks = this.getHookItems();
 
 		this.logService.debug(`[CopilotCLICustomizationProvider] agents (${agents.length}): ${agents.map(a => a.name).join(', ') || '(none)'}`);
 		this.logService.debug(`[CopilotCLICustomizationProvider] instructions (${instructions.length}): ${instructions.map(i => i.name).join(', ') || '(none)'}`);
 		this.logService.debug(`[CopilotCLICustomizationProvider] skills (${skills.length}): ${skills.map(s => s.name).join(', ') || '(none)'}`);
+		this.logService.debug(`[CopilotCLICustomizationProvider] hooks (${hooks.length}): ${hooks.map(h => h.name).join(', ') || '(none)'}`);
 
-		const items = [...agents, ...instructions, ...skills];
+		const items = [...agents, ...instructions, ...skills, ...hooks];
 		this.logService.debug(`[CopilotCLICustomizationProvider] total: ${items.length} items`);
 		return items;
 	}
@@ -91,6 +95,18 @@ export class CopilotCLICustomizationProvider extends Disposable implements vscod
 			name: deriveNameFromUri(s.uri, SKILL_FILENAME),
 		}));
 	}
+
+	/**
+	 * Collects all hook items from the prompt file service.
+	 * Each item is a hook configuration file (JSON).
+	 */
+	private getHookItems(): vscode.ChatSessionCustomizationItem[] {
+		return this.chatPromptFileService.hooks.map(h => ({
+			uri: h.uri,
+			type: vscode.ChatSessionCustomizationType.Hook,
+			name: basename(h.uri).replace(/\.json$/i, ''),
+		}));
+	}
 }
 
 function deriveNameFromUri(uri: vscode.Uri, extensionOrFilename: string): string {

src/extension/chatSessions/vscode-node/test/copilotCLICustomizationProvider.spec.ts

@@ -58,27 +58,34 @@ class MockChatPromptFileService extends mock<IChatPromptFileService>() {
 	override readonly onDidChangeInstructions = this._onDidChangeInstructions.event;
 	private readonly _onDidChangeSkills = new Emitter<void>();
 	override readonly onDidChangeSkills = this._onDidChangeSkills.event;
+	private readonly _onDidChangeHooks = new Emitter<void>();
+	override readonly onDidChangeHooks = this._onDidChangeHooks.event;
 
 	private _customAgents: vscode.ChatResource[] = [];
 	private _instructions: vscode.ChatResource[] = [];
 	private _skills: vscode.ChatResource[] = [];
+	private _hooks: vscode.ChatResource[] = [];
 
 	override get customAgents(): readonly vscode.ChatResource[] { return this._customAgents; }
 	override get instructions(): readonly vscode.ChatResource[] { return this._instructions; }
 	override get skills(): readonly vscode.ChatResource[] { return this._skills; }
+	override get hooks(): readonly vscode.ChatResource[] { return this._hooks; }
 
 	setCustomAgents(agents: vscode.ChatResource[]) { this._customAgents = agents; }
 	setInstructions(instructions: vscode.ChatResource[]) { this._instructions = instructions; }
 	setSkills(skills: vscode.ChatResource[]) { this._skills = skills; }
+	setHooks(hooks: vscode.ChatResource[]) { this._hooks = hooks; }
 
 	fireCustomAgentsChanged() { this._onDidChangeCustomAgents.fire(); }
 	fireInstructionsChanged() { this._onDidChangeInstructions.fire(); }
 	fireSkillsChanged() { this._onDidChangeSkills.fire(); }
+	fireHooksChanged() { this._onDidChangeHooks.fire(); }
 
 	override dispose() {
 		this._onDidChangeCustomAgents.dispose();
 		this._onDidChangeInstructions.dispose();
 		this._onDidChangeSkills.dispose();
+		this._onDidChangeHooks.dispose();
 	}
 }
 
@@ -130,13 +137,14 @@ describe('CopilotCLICustomizationProvider', () => {
 			expect(CopilotCLICustomizationProvider.metadata.iconId).toBe('worktree');
 		});
 
-		it('supports Agent, Skill, and Instructions types', () => {
+		it('supports Agent, Skill, Instructions, and Hook types', () => {
 			const supported = CopilotCLICustomizationProvider.metadata.supportedTypes;
 			expect(supported).toBeDefined();
-			expect(supported).toHaveLength(3);
+			expect(supported).toHaveLength(4);
 			expect(supported).toContain(FakeChatSessionCustomizationType.Agent);
 			expect(supported).toContain(FakeChatSessionCustomizationType.Skill);
 			expect(supported).toContain(FakeChatSessionCustomizationType.Instructions);
+			expect(supported).toContain(FakeChatSessionCustomizationType.Hook);
 		});
 
 		it('only returns items whose type is in supportedTypes', async () => {
@@ -240,9 +248,39 @@ describe('CopilotCLICustomizationProvider', () => {
 			mockCopilotCLIAgents.setAgents([makeAgentInfo('explore', 'Explore')]);
 			mockPromptFileService.setInstructions([{ uri: URI.file('/workspace/.github/b.instructions.md') }]);
 			mockPromptFileService.setSkills([{ uri: URI.file('/workspace/.github/skills/c/SKILL.md') }]);
+			mockPromptFileService.setHooks([{ uri: URI.file('/workspace/.copilot/hooks/pre-commit.json') }]);
 
 			const items = await provider.provideChatSessionCustomizations(undefined!);
-			expect(items).toHaveLength(3);
+			expect(items).toHaveLength(4);
+		});
+
+		it('returns hooks with correct type and name', async () => {
+			const uri = URI.file('/workspace/.copilot/hooks/diagnostics.json');
+			mockPromptFileService.setHooks([{ uri }]);
+
+			const items = await provider.provideChatSessionCustomizations(undefined!);
+			expect(items).toHaveLength(1);
+			expect(items[0].uri).toBe(uri);
+			expect(items[0].type).toBe(FakeChatSessionCustomizationType.Hook);
+			expect(items[0].name).toBe('diagnostics');
+		});
+
+		it('strips .json extension from hook file name', async () => {
+			mockPromptFileService.setHooks([{ uri: URI.file('/workspace/.copilot/hooks/security-checks.json') }]);
+
+			const items = await provider.provideChatSessionCustomizations(undefined!);
+			expect(items[0].name).toBe('security-checks');
+		});
+
+		it('returns multiple hooks', async () => {
+			mockPromptFileService.setHooks([
+				{ uri: URI.file('/workspace/.copilot/hooks/hooks.json') },
+				{ uri: URI.file('/workspace/.copilot/hooks/diagnostics.json') },
+			]);
+
+			const items = await provider.provideChatSessionCustomizations(undefined!);
+			const hookItems = items.filter((i: vscode.ChatSessionCustomizationItem) => i.type === FakeChatSessionCustomizationType.Hook);
+			expect(hookItems).toHaveLength(2);
 		});
 	});
 
@@ -271,6 +309,14 @@ describe('CopilotCLICustomizationProvider', () => {
 			expect(fired).toBe(true);
 		});
 
+		it('fires when hooks change', () => {
+			let fired = false;
+			disposables.add(provider.onDidChange(() => { fired = true; }));
+
+			mockPromptFileService.fireHooksChanged();
+			expect(fired).toBe(true);
+		});
+
 		it('fires when ICopilotCLIAgents agents change', () => {
 			let fired = false;
 			disposables.add(provider.onDidChange(() => { fired = true; }));

src/extension/vscode.proposed.chatPromptFiles.d.ts

@@ -78,6 +78,28 @@ declare module 'vscode' {
 
 	// #endregion
 
+	// #region HookProvider
+
+	/**
+	 * A provider that supplies hook configuration resources (from hooks JSON files).
+	 */
+	export interface ChatHookProvider {
+		/**
+		 * An optional event to signal that hooks have changed.
+		 */
+		readonly onDidChangeHooks?: Event<void>;
+
+		/**
+		 * Provide the list of hook configuration files available.
+		 * @param context Context for the provide call.
+		 * @param token A cancellation token.
+		 * @returns An array of hook resources or a promise that resolves to such.
+		 */
+		provideHooks(context: unknown, token: CancellationToken): ProviderResult<ChatResource[]>;
+	}
+
+	// #endregion
+
 	// #region SkillProvider
 
 	/**
@@ -136,6 +158,18 @@ declare module 'vscode' {
 		 */
 		export const skills: readonly ChatResource[];
 
+		/**
+		 * An event that fires when the list of {@link hooks hooks} changes.
+		 */
+		export const onDidChangeHooks: Event<void>;
+
+		/**
+		 * The list of currently available hook configuration files.
+		 * These are JSON files that define lifecycle hooks from all sources
+		 * (workspace, user, and extension-provided).
+		 */
+		export const hooks: readonly ChatResource[];
+
 		/**
 		 * Register a provider for custom agents.
 		 * @param provider The custom agent provider.
@@ -163,6 +197,13 @@ declare module 'vscode' {
 		 * @returns A disposable that unregisters the provider when disposed.
 		 */
 		export function registerSkillProvider(provider: ChatSkillProvider): Disposable;
+
+		/**
+		 * Register a provider for hooks.
+		 * @param provider The hook provider.
+		 * @returns A disposable that unregisters the provider when disposed.
+		 */
+		export function registerHookProvider(provider: ChatHookProvider): Disposable;
 	}
 
 	// #endregion