fix: prefer powershell cli shims on Windows

Author: 0xranx

dist/engines/shared.d.ts.map

@@ -92,4 +92,55 @@ describe('engine shared spawn helpers', () => {
       options,
     );
   });
+
+  it('spawnCommand prefers a sibling PowerShell shim on Windows when available', async () => {
+    const originalPlatform = process.platform;
+    Object.defineProperty(process, 'platform', { value: 'win32' });
+    const crossSpawnMock = vi.fn();
+    try {
+      vi.doMock('cross-spawn', () => ({
+        default: crossSpawnMock,
+      }));
+      vi.doMock('node:child_process', async (importOriginal) => {
+        const original = await importOriginal<typeof import('node:child_process')>();
+        return {
+          ...original,
+          execFileSync: vi.fn((cmd: string, args: string[]) => {
+            if (cmd === 'where' && args[0] === 'claude') return 'C:\\Users\\me\\AppData\\Roaming\\npm\\claude.cmd\r\n';
+            if (cmd === 'where' && args[0] === 'powershell.exe')
+              return 'C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\powershell.exe\r\n';
+            return '';
+          }),
+        };
+      });
+      vi.doMock('node:fs', async (importOriginal) => {
+        const original = await importOriginal<typeof import('node:fs')>();
+        return {
+          ...original,
+          existsSync: vi.fn((path: string) => path === 'C:\\Users\\me\\AppData\\Roaming\\npm\\claude.ps1'),
+        };
+      });
+
+      const { spawnCommand } = await import('../engines/shared.js');
+      const options = { stdio: 'ignore' as const };
+      spawnCommand('claude', ['--version'], options);
+
+      expect(crossSpawnMock).toHaveBeenCalledWith(
+        'C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\powershell.exe',
+        [
+          '-NoLogo',
+          '-NoProfile',
+          '-NonInteractive',
+          '-ExecutionPolicy',
+          'Bypass',
+          '-File',
+          'C:\\Users\\me\\AppData\\Roaming\\npm\\claude.ps1',
+          '--version',
+        ],
+        options,
+      );
+    } finally {
+      Object.defineProperty(process, 'platform', { value: originalPlatform });
+    }
+  });
 });

dist/engines/shared.js

@@ -54,4 +54,46 @@ describe('Windows CLI launch smoke', () => {
     expect(events.some((event) => event.type === 'done' && event.sessionId === 'win-shim')).toBe(true);
     expect(events.some((event) => event.type === 'error')).toBe(false);
   });
+
+  itWindows('prefers claude.ps1 over claude.cmd when both exist', async () => {
+    const workspace = await mkdtemp(join(tmpdir(), 'golem-win-workspace-'));
+    const fakeBin = await mkdtemp(join(tmpdir(), 'golem-win-bin-'));
+    tempDirs.push(workspace, fakeBin);
+
+    await mkdir(join(workspace, 'skills', 'general'), { recursive: true });
+    await writeFile(join(workspace, 'golem.yaml'), 'name: windows-smoke\nengine: claude-code\n', 'utf-8');
+    await writeFile(
+      join(workspace, 'skills', 'general', 'SKILL.md'),
+      '---\nname: general\ndescription: General assistant\n---\n# General\n',
+      'utf-8',
+    );
+
+    await writeFile(
+      join(fakeBin, 'claude.cmd'),
+      ['@echo off', 'echo plain text from cmd shim', ''].join('\r\n'),
+      'utf-8',
+    );
+    await writeFile(
+      join(fakeBin, 'claude.ps1'),
+      [
+        'Write-Output \'{"type":"assistant","message":{"content":[{"type":"text","text":"ps1 ok"}]}}\'',
+        'Write-Output \'{"type":"result","is_error":false,"session_id":"win-ps1"}\'',
+        '',
+      ].join('\r\n'),
+      'utf-8',
+    );
+
+    originalPath = process.env.PATH;
+    process.env.PATH = [fakeBin, originalPath].filter(Boolean).join(delimiter);
+
+    const assistant = createAssistant({ dir: workspace, timeoutMs: 5_000 });
+    const events: StreamEvent[] = [];
+    for await (const event of assistant.chat('hello from windows')) {
+      events.push(event);
+    }
+
+    expect(events).toContainEqual({ type: 'text', content: 'ps1 ok' });
+    expect(events.some((event) => event.type === 'done' && event.sessionId === 'win-ps1')).toBe(true);
+    expect(events.some((event) => event.type === 'error')).toBe(false);
+  });
 });

dist/engines/shared.js.map

@@ -47,6 +47,17 @@ export function prependPathEntries(
 
 export function spawnCommand(command: string, args: string[], options: SpawnOptions) {
   const resolved = resolveOnPath(command) || command;
+  if (process.platform === 'win32' && /\.cmd$/i.test(resolved)) {
+    const ps1Path = resolved.replace(/\.cmd$/i, '.ps1');
+    const powershell = resolveOnPath('powershell.exe') || resolveOnPath('pwsh.exe');
+    if (existsSync(ps1Path) && powershell) {
+      return crossSpawn(
+        powershell,
+        ['-NoLogo', '-NoProfile', '-NonInteractive', '-ExecutionPolicy', 'Bypass', '-File', ps1Path, ...args],
+        options,
+      );
+    }
+  }
   return crossSpawn(resolved, args, options);
 }