fix(subagent-codex): support Windows command shims

packages/subagent/subagent-codex/src/run.ts

@@ -24,6 +24,23 @@ import { CodexAppServerWire } from './wire.ts'
 /** Default POSIX grace between subprocess termination tiers. */
 export const DEFAULT_DISPOSE_GRACE_MS = 3_000
 
+/**
+ * Resolve the fixed app-server command for a platform.
+ *
+ * Windows npm and pnpm installs expose `codex.cmd`, which requires `cmd.exe`;
+ * the argv is constant so no task or configuration text enters the
+ * shell boundary.
+ * @param platform - host platform used to select the executable boundary.
+ * @returns argv for the fixed Codex app-server command.
+ */
+export function codexAppServerArgv(
+  platform: NodeJS.Platform = process.platform,
+): string[] {
+  return platform === 'win32'
+    ? ['cmd.exe', '/d', '/s', '/c', 'codex', 'app-server', '--stdio']
+    : ['codex', 'app-server', '--stdio']
+}
+
 /** Fully resolved inputs for one Codex app-server run. */
 export interface CodexRunSpec {
   /** Parent Session workspace, also supplied to `thread/start`. */
@@ -106,7 +123,7 @@ export async function startCodexRun(
   }
 
   const child = spec.spawn({
-    argv: ['codex', 'app-server', '--stdio'],
+    argv: codexAppServerArgv(),
     cwd: spec.cwd,
     stdio: { stdin: 'pipe', stdout: 'pipe', stderr: 'inherit' },
     graceMs: spec.disposeGraceMs,

packages/subagent/subagent-codex/tests/subagent-codex.spec.ts

@@ -15,6 +15,7 @@ import LocalSubprocessService from '@deepseek-ai/dsh-subprocess-local'
 import * as codex from '../src/index.ts'
 import * as invariant from '../src/invariant.ts'
 import {
+  codexAppServerArgv,
   DEFAULT_DISPOSE_GRACE_MS,
   disposeCodexChild,
   startCodexRun,
@@ -259,6 +260,19 @@ function turnCompleted(
 }
 
 describe('task admission and package contracts', () => {
+  it('resolves the fixed app-server command through the Windows npm shim boundary', () => {
+    expect(codexAppServerArgv('win32')).toEqual([
+      'cmd.exe',
+      '/d',
+      '/s',
+      '/c',
+      'codex',
+      'app-server',
+      '--stdio',
+    ])
+    expect(codexAppServerArgv('linux')).toEqual(['codex', 'app-server', '--stdio'])
+  })
+
   it('accepts one or more text blocks and rejects empty or non-text tasks', () => {
     expect(textTask([
       { type: 'text', text: 'one' },
@@ -868,7 +882,7 @@ describe('run lifecycle and quiescence', () => {
     child.peer.respond(threadStart, { thread: { id: 'thread-1', ephemeral: true } })
     const run = await starting
     expect(spawn).toHaveBeenCalledWith({
-      argv: ['codex', 'app-server', '--stdio'],
+      argv: codexAppServerArgv(),
       cwd: process.cwd(),
       stdio: { stdin: 'pipe', stdout: 'pipe', stderr: 'inherit' },
       graceMs: DEFAULT_DISPOSE_GRACE_MS,