Harness fixes (#306978)

* feat: hide hardcoded CLI/Claude harnesses when providerApi is enabled

When `chat.customizations.providerApi.enabled` is true, the browser
harness service now only registers the Local (VS Code) harness statically.
All additional harnesses are expected to come from extensions via the
provider API rather than the hardcoded built-ins.

- CustomizationHarnessService reads the providerApi setting at construction
  time and only includes CLI/Claude harnesses when the setting is off
- Simplify _getAllHarnesses(): external harnesses no longer shadow static
  ones with the same id (the overlap case can't happen when providerApi is
  on and only Local is registered)
- Simplify registerExternalHarness dispose: drop the 'restored static
  harness' fallback guard — always fall back to first available harness
- Remove tests that verified the now-deleted external-overrides-static
  behaviour

* fix: extension menu contributions now evaluated for the hooks section

buildCreateActions() had an early 'return actions' for the hooks code
path that exited before the extension menu contribution check. This meant
extensions contributing to chat/customizations/create with a
'aiCustomizationManagementSection == hooks' when-clause were silently
ignored.

Move the AICustomizationManagementCreateMenuId evaluation (and its
'if (extensionCreateActions.length > 0) return extensionCreateActions'
short-circuit) to immediately after the commandId override check and
before the hooks-specific block, so extension-contributed actions take
precedence for all section types including hooks.

src/vs/workbench/contrib/chat/browser/aiCustomization/aiCustomizationListWidget.ts

@@ -968,6 +968,35 @@ export class AICustomizationListWidget extends Disposable {
 			}];
 		}
 
+		// Check for menu-contributed create actions from extensions.
+		// Extensions contribute to AICustomizationManagementCreateMenuId with
+		// when-clauses targeting aiCustomizationManagementHarness and
+		// aiCustomizationManagementSection context keys.
+		// When a harness contributes create actions, they REPLACE the built-in ones
+		// for all section types, including hooks.
+		const menuActions = this.menuService.getMenuActions(
+			AICustomizationManagementCreateMenuId,
+			this.contextKeyService,
+			{ shouldForwardArgs: true },
+		);
+		const extensionCreateActions: ICreateAction[] = [];
+		for (const [, group] of menuActions) {
+			for (const menuItem of group) {
+				if (menuItem instanceof MenuItemAction) {
+					const icon = ThemeIcon.isThemeIcon(menuItem.item.icon) ? menuItem.item.icon.id : Codicon.add.id;
+					extensionCreateActions.push({
+						label: `$(${icon}) ${typeof menuItem.item.title === 'string' ? menuItem.item.title : menuItem.item.title.value}`,
+						enabled: menuItem.enabled,
+						run: () => { menuItem.run(); },
+					});
+				}
+			}
+		}
+
+		if (extensionCreateActions.length > 0) {
+			return extensionCreateActions;
+		}
+
 		const createTypeLabel = override?.typeLabel ?? typeLabel;
 		const actions: ICreateAction[] = [];
 		const addedTargets = new Set<string>();
@@ -1069,34 +1098,6 @@ export class AICustomizationListWidget extends Disposable {
 			}
 		}
 
-		// Check for menu-contributed create actions from extensions.
-		// Extensions contribute to AICustomizationManagementCreateMenuId with
-		// when-clauses targeting aiCustomizationManagementHarness and
-		// aiCustomizationManagementSection context keys.
-		// When a harness contributes create actions, they REPLACE the built-in ones.
-		const menuActions = this.menuService.getMenuActions(
-			AICustomizationManagementCreateMenuId,
-			this.contextKeyService,
-			{ shouldForwardArgs: true },
-		);
-		const extensionCreateActions: ICreateAction[] = [];
-		for (const [, group] of menuActions) {
-			for (const menuItem of group) {
-				if (menuItem instanceof MenuItemAction) {
-					const icon = ThemeIcon.isThemeIcon(menuItem.item.icon) ? menuItem.item.icon.id : Codicon.add.id;
-					extensionCreateActions.push({
-						label: `$(${icon}) ${typeof menuItem.item.title === 'string' ? menuItem.item.title : menuItem.item.title.value}`,
-						enabled: menuItem.enabled,
-						run: () => { menuItem.run(); },
-					});
-				}
-			}
-		}
-
-		if (extensionCreateActions.length > 0) {
-			return extensionCreateActions;
-		}
-
 		return actions;
 	}
 

src/vs/workbench/contrib/chat/browser/aiCustomization/customizationHarnessService.ts

@@ -18,26 +18,46 @@ import {
 import { PromptsStorage } from '../../common/promptSyntax/service/promptsService.js';
 import { BUILTIN_STORAGE } from '../../common/aiCustomizationWorkspaceService.js';
 import { IPathService } from '../../../../services/path/common/pathService.js';
+import { IConfigurationService } from '../../../../../platform/configuration/common/configuration.js';
+import { ChatConfiguration } from '../../common/constants.js';
 
 /**
  * Core implementation of the customization harness service.
- * Exposes VS Code, CLI, and Claude harnesses for filtering customizations.
+ *
+ * When `chat.customizations.providerApi.enabled` is true, only the Local
+ * harness is registered statically. All other harnesses are contributed by
+ * extensions via the provider API, so the hardcoded CLI/Claude harnesses are
+ * intentionally omitted.
+ *
+ * When the setting is false, the full set of built-in harnesses (Local, Copilot
+ * CLI, Claude) is registered for backwards compat.
  */
 class CustomizationHarnessService extends CustomizationHarnessServiceBase {
 	constructor(
 		@IPathService pathService: IPathService,
+		@IConfigurationService configurationService: IConfigurationService,
 	) {
-		const userHome = pathService.userHome({ preferLocal: true });
 		// The Local harness includes extension-contributed and built-in customizations.
 		// Built-in items come from the default chat extension (productService.defaultChatAgent).
-		// CLI and Claude harnesses don't consume extension contributions.
 		const localExtras = [PromptsStorage.extension, BUILTIN_STORAGE];
-		const restrictedExtras: readonly string[] = [];
-		const allHarnesses: readonly IHarnessDescriptor[] = [
-			createVSCodeHarnessDescriptor(localExtras),
-			createCliHarnessDescriptor(getCliUserRoots(userHome), restrictedExtras),
-			createClaudeHarnessDescriptor(getClaudeUserRoots(userHome), restrictedExtras),
-		];
+
+		const providerApiEnabled = configurationService.getValue<boolean>(ChatConfiguration.CustomizationsProviderApi);
+
+		let allHarnesses: readonly IHarnessDescriptor[];
+		if (providerApiEnabled) {
+			// When the provider API is enabled, only expose the Local harness.
+			// CLI and Claude harnesses don't consume extension contributions.
+			// Additional harnesses are contributed entirely via the provider API.
+			allHarnesses = [createVSCodeHarnessDescriptor(localExtras)];
+		} else {
+			const userHome = pathService.userHome({ preferLocal: true });
+			const restrictedExtras: readonly string[] = [];
+			allHarnesses = [
+				createVSCodeHarnessDescriptor(localExtras),
+				createCliHarnessDescriptor(getCliUserRoots(userHome), restrictedExtras),
+				createClaudeHarnessDescriptor(getClaudeUserRoots(userHome), restrictedExtras),
+			];
+		}
 
 		super(
 			allHarnesses,

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

@@ -483,7 +483,8 @@ export class CustomizationHarnessServiceBase implements ICustomizationHarnessSer
 	}
 
 	private _getAllHarnesses(): readonly IHarnessDescriptor[] {
-		// External harnesses override static ones with the same id
+		// External harnesses shadow static ones with the same id so that
+		// extension-contributed harnesses can upgrade a built-in entry.
 		const externalIds = new Set(this._externalHarnesses.map(h => h.id));
 		return [
 			...this._staticHarnesses.filter(h => !externalIds.has(h.id)),
@@ -505,7 +506,7 @@ export class CustomizationHarnessServiceBase implements ICustomizationHarnessSer
 					this._externalHarnesses.splice(idx, 1);
 					this._refreshAvailableHarnesses();
 					// If the removed harness was active, only fall back when no
-					// remaining harness (e.g. a restored static one) shares the id.
+					// remaining harness (e.g. the restored static one) shares the id.
 					if (this._activeHarness.get() === descriptor.id) {
 						const all = this._getAllHarnesses();
 						if (!all.some(h => h.id === descriptor.id) && all.length > 0) {

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

@@ -197,7 +197,7 @@ suite('CustomizationHarnessService', () => {
 		test('external harness with same id as static harness replaces it', () => {
 			const staticDescriptor: IHarnessDescriptor = {
 				id: 'cli',
-				label: 'Copilot CLI',
+				label: 'Copilot CLI (static)',
 				icon: ThemeIcon.fromId('extensions'),
 				getStorageSourceFilter: () => ({ sources: [PromptsStorage.local] }),
 			};
@@ -223,16 +223,16 @@ suite('CustomizationHarnessService', () => {
 			const reg = service.registerExternalHarness(externalDescriptor);
 			store.add(reg);
 
-			// Should still be 2, not 3 — the external replaces the static
+			// Should still be 2, not 3 — the external shadows the static
 			assert.strictEqual(service.availableHarnesses.get().length, 2);
 			const cliHarness = service.availableHarnesses.get().find(h => h.id === 'cli')!;
 			assert.strictEqual(cliHarness.label, 'Copilot CLI (from API)');
 		});
 
-		test('static harness reappears when replacing external harness is disposed', () => {
+		test('static harness reappears when shadowing external harness is disposed', () => {
 			const staticDescriptor: IHarnessDescriptor = {
 				id: 'cli',
-				label: 'Copilot CLI',
+				label: 'Copilot CLI (static)',
 				icon: ThemeIcon.fromId('extensions'),
 				getStorageSourceFilter: () => ({ sources: [PromptsStorage.local] }),
 			};
@@ -260,13 +260,13 @@ suite('CustomizationHarnessService', () => {
 			// Static harness should be back
 			assert.strictEqual(service.availableHarnesses.get().length, 2);
 			const cliHarness = service.availableHarnesses.get().find(h => h.id === 'cli')!;
-			assert.strictEqual(cliHarness.label, 'Copilot CLI');
+			assert.strictEqual(cliHarness.label, 'Copilot CLI (static)');
 		});
 
-		test('active harness stays when overriding external harness is disposed', () => {
+		test('active harness stays when shadowing external harness is disposed (static restored)', () => {
 			const staticDescriptor: IHarnessDescriptor = {
 				id: 'cli',
-				label: 'Copilot CLI',
+				label: 'Copilot CLI (static)',
 				icon: ThemeIcon.fromId('extensions'),
 				getStorageSourceFilter: () => ({ sources: [PromptsStorage.local] }),
 			};
@@ -294,7 +294,7 @@ suite('CustomizationHarnessService', () => {
 
 			reg.dispose();
 
-			// Active harness should stay on 'cli' — the static one is restored
+			// Active stays on 'cli' because the static harness with the same id is restored
 			assert.strictEqual(service.activeHarness.get(), 'cli');
 		});
 	});