fix: validate override piece via resolver including ensemble scope

src/__tests__/selectAndExecute-autoPr.test.ts

@@ -33,6 +33,7 @@ vi.mock('../infra/config/index.js', () => ({
   resolvePieceConfigValue: (...args: unknown[]) => mockResolvePieceConfigValue(...args),
   listPieces: vi.fn(() => ['default']),
   listPieceEntries: vi.fn(() => []),
+  loadPieceByIdentifier: vi.fn((identifier: string) => (identifier === 'default' ? { name: 'default' } : null)),
   isPiecePath: vi.fn(() => false),
 }));
 
@@ -86,11 +87,13 @@ vi.mock('../features/pieceSelection/index.js', () => ({
 }));
 
 import { confirm } from '../shared/prompt/index.js';
+import { loadPieceByIdentifier } from '../infra/config/index.js';
 import { createSharedClone, autoCommitAndPush, summarizeTaskName } from '../infra/task/index.js';
 import { selectPiece } from '../features/pieceSelection/index.js';
 import { selectAndExecuteTask, determinePiece } from '../features/tasks/execute/selectAndExecute.js';
 
 const mockConfirm = vi.mocked(confirm);
+const mockLoadPieceByIdentifier = vi.mocked(loadPieceByIdentifier);
 const mockCreateSharedClone = vi.mocked(createSharedClone);
 const mockAutoCommitAndPush = vi.mocked(autoCommitAndPush);
 const mockSummarizeTaskName = vi.mocked(summarizeTaskName);
@@ -180,6 +183,14 @@ describe('resolveAutoPr default in selectAndExecuteTask', () => {
     expect(mockSelectPiece).toHaveBeenCalledWith('/project');
   });
 
+  it('should accept ensemble scoped piece override when it exists', async () => {
+    mockLoadPieceByIdentifier.mockReturnValueOnce({ name: '@nrslib/takt-packages/critical-thinking' } as never);
+
+    const selected = await determinePiece('/project', '@nrslib/takt-packages/critical-thinking');
+
+    expect(selected).toBe('@nrslib/takt-packages/critical-thinking');
+  });
+
   it('should fail task record when executeTask throws', async () => {
     mockConfirm.mockResolvedValue(true);
     mockSummarizeTaskName.mockResolvedValue('test-task');

src/features/tasks/execute/selectAndExecute.ts

@@ -7,12 +7,11 @@
  */
 
 import {
-  listPieces,
+  loadPieceByIdentifier,
   isPiecePath,
 } from '../../../infra/config/index.js';
 import { confirm } from '../../../shared/prompt/index.js';
 import { createSharedClone, summarizeTaskName, getCurrentBranch, TaskRunner } from '../../../infra/task/index.js';
-import { DEFAULT_PIECE_NAME } from '../../../shared/constants.js';
 import { info, error, withProgress } from '../../../shared/ui/index.js';
 import { createLogger } from '../../../shared/utils/index.js';
 import { executeTask } from './taskExecution.js';
@@ -30,9 +29,8 @@ export async function determinePiece(cwd: string, override?: string): Promise<st
     if (isPiecePath(override)) {
       return override;
     }
-    const availablePieces = listPieces(cwd);
+    const resolvedPiece = loadPieceByIdentifier(override, cwd);
-    const knownPieces = availablePieces.length === 0 ? [DEFAULT_PIECE_NAME] : availablePieces;
+    if (!resolvedPiece) {
-    if (!knownPieces.includes(override)) {
       error(`Piece not found: ${override}`);
       return null;
     }