fix(windows): run dev-install's external commands without a shell

__tests__/dev-install.test.js

@@ -163,14 +163,126 @@ describe('dev-install script', () => {
     });
 
     test('removes marketplace for Claude', () => {
-      expect(devInstallSource.includes('plugin marketplace remove')).toBe(true);
+      expect(devInstallSource.includes("'plugin', 'marketplace', 'remove', 'agent-sh/agentsys'")).toBe(true);
     });
 
     test('copies to ~/.agentsys for OpenCode/Codex', () => {
       expect(devInstallSource.includes('copyToAgentSys')).toBe(true);
     });
   });
 
+  describe('external commands', () => {
+    const realPlatform = process.platform;
+    const realComspec = process.env.comspec;
+
+    function setPlatform(platform) {
+      Object.defineProperty(process, 'platform', { value: platform, configurable: true });
+    }
+
+    afterEach(() => {
+      setPlatform(realPlatform);
+      if (realComspec === undefined) {
+        delete process.env.comspec;
+      } else {
+        process.env.comspec = realComspec;
+      }
+      jest.resetModules();
+      jest.clearAllMocks();
+    });
+
+    /**
+     * Load dev-install with child_process mocked, on the given platform.
+     *
+     * The platform is set before the require because resolveExecutableForPlatform
+     * and planShimSpawn read process.platform when runCommand calls them. comspec
+     * is pinned for the same reason: a real Windows host has COMSPEC set to an
+     * absolute path, so reading it would make the expected shell differ per host.
+     */
+    function loadWithPlatform(platform) {
+      setPlatform(platform);
+      process.env.comspec = 'cmd.exe';
+      jest.resetModules();
+      const childProcess = require('child_process');
+      jest.spyOn(childProcess, 'execFileSync').mockReturnValue('');
+      return {
+        devInstall: require(devInstallPath),
+        execFileSync: childProcess.execFileSync
+      };
+    }
+
+    test('no execSync anywhere - every command is an argv list', () => {
+      expect(devInstallSource.includes('execSync(')).toBe(false);
+      expect(devInstallSource.includes('execFileSync')).toBe(true);
+    });
+
+    test('routes the claude shim through cmd.exe on Windows', () => {
+      const { devInstall, execFileSync } = loadWithPlatform('win32');
+
+      devInstall.runCommand('claude', ['plugin', 'uninstall', 'core@agentsys'], { stdio: 'pipe' });
+
+      expect(execFileSync).toHaveBeenCalledWith(
+        'cmd.exe',
+        ['/d', '/s', '/c', '""claude.cmd" "plugin" "uninstall" "core@agentsys""'],
+        { stdio: 'pipe', windowsVerbatimArguments: true }
+      );
+    });
+
+    test('spawns claude directly on other platforms', () => {
+      const { devInstall, execFileSync } = loadWithPlatform('linux');
+
+      devInstall.runCommand('claude', ['plugin', 'uninstall', 'core@agentsys'], { stdio: 'pipe' });
+
+      expect(execFileSync).toHaveBeenCalledWith(
+        'claude',
+        ['plugin', 'uninstall', 'core@agentsys'],
+        { stdio: 'pipe' }
+      );
+    });
+
+    test('resolves npm to its shim and keeps the cwd', () => {
+      const { devInstall, execFileSync } = loadWithPlatform('win32');
+
+      devInstall.runCommand('npm', ['install', '--production'], { cwd: 'C:\\Users\\dev\\.agentsys', stdio: 'pipe' });
+
+      expect(execFileSync).toHaveBeenCalledWith(
+        'cmd.exe',
+        ['/d', '/s', '/c', '""npm.cmd" "install" "--production""'],
+        { cwd: 'C:\\Users\\dev\\.agentsys', stdio: 'pipe', windowsVerbatimArguments: true }
+      );
+    });
+
+    test('a plugin name holding shell metacharacters stays one argument', () => {
+      const { devInstall, execFileSync } = loadWithPlatform('linux');
+
+      devInstall.runCommand('claude', ['plugin', 'uninstall', 'core & calc@agentsys'], { stdio: 'pipe' });
+
+      const [, args] = execFileSync.mock.calls[0];
+      expect(args).toEqual(['plugin', 'uninstall', 'core & calc@agentsys']);
+    });
+
+    test('commandExists asks where.exe on Windows and which elsewhere', () => {
+      const win = loadWithPlatform('win32');
+      win.devInstall.commandExists('claude');
+      expect(win.execFileSync.mock.calls[0][0]).toBe('where.exe');
+      expect(win.execFileSync.mock.calls[0][1]).toEqual(['claude']);
+
+      const linux = loadWithPlatform('linux');
+      linux.devInstall.commandExists('claude');
+      expect(linux.execFileSync).toHaveBeenCalledWith('which', ['claude'], { stdio: 'pipe' });
+    });
+
+    test('commandExists reports false when the lookup fails', () => {
+      setPlatform('linux');
+      jest.resetModules();
+      const childProcess = require('child_process');
+      jest.spyOn(childProcess, 'execFileSync').mockImplementation(() => {
+        throw new Error('not found');
+      });
+
+      expect(require(devInstallPath).commandExists('claude')).toBe(false);
+    });
+  });
+
   describe('output', () => {
     test('logs with [dev-install] prefix', () => {
       expect(devInstallSource.includes('[dev-install]')).toBe(true);

scripts/dev-install.js

@@ -19,7 +19,7 @@
  *   - Runs synchronously for quick feedback
  */
 
-const { execSync } = require('child_process');
+const { execFileSync } = require('child_process');
 const fs = require('fs');
 const path = require('path');
 
@@ -28,6 +28,11 @@ const SOURCE_DIR = path.join(__dirname, '..');
 const VERSION = require(path.join(SOURCE_DIR, 'package.json')).version;
 const discovery = require(path.join(SOURCE_DIR, 'lib', 'discovery'));
 const transforms = require(path.join(SOURCE_DIR, 'lib', 'adapter-transforms'));
+const {
+  resolveExecutableForPlatform,
+  planShimSpawn,
+  shimSpawnOptions
+} = require(path.join(SOURCE_DIR, 'lib', 'utils', 'command-parser'));
 
 // Target directories
 const HOME = process.env.HOME || process.env.USERPROFILE;
@@ -54,9 +59,25 @@ function log(msg) {
   console.log(`[dev-install] ${msg}`);
 }
 
+/**
+ * Run one external command with an argv list instead of a shell string.
+ *
+ * The commands here (`claude`, `npm`) are .cmd shims on Windows, which need two
+ * separate fixes: resolveExecutableForPlatform supplies the extension that
+ * execFileSync will not look up itself, and planShimSpawn routes the shim
+ * through cmd.exe, since Node has refused to spawn .cmd directly since the
+ * CVE-2024-27980 fix. Plugin names reach this from discovery on disk, so they
+ * stay argv elements - a shell string would make a directory named `a & b` a
+ * second command.
+ */
+function runCommand(command, args, options = {}) {
+  const plan = planShimSpawn(resolveExecutableForPlatform(command), args);
+  return execFileSync(plan.file, plan.args, shimSpawnOptions(plan, options));
+}
+
 function commandExists(cmd) {
   try {
-    execSync(`${process.platform === 'win32' ? 'where' : 'which'} ${cmd}`, { stdio: 'pipe' });
+    runCommand(process.platform === 'win32' ? 'where.exe' : 'which', [cmd], { stdio: 'pipe' });
     return true;
   } catch {
     return false;
@@ -269,7 +290,7 @@ function installClaude() {
 
   // Remove marketplace plugins first
   try {
-    execSync('claude plugin marketplace remove agent-sh/agentsys', { stdio: 'pipe' });
+    runCommand('claude', ['plugin', 'marketplace', 'remove', 'agent-sh/agentsys'], { stdio: 'pipe' });
     log('  Removed marketplace');
   } catch {
     // May not exist
@@ -280,7 +301,7 @@ function installClaude() {
     // Uninstall both current and pre-rename plugin IDs
     for (const suffix of ['agentsys', 'awesome-slash']) {
       try {
-        execSync(`claude plugin uninstall ${plugin}@${suffix}`, { stdio: 'pipe' });
+        runCommand('claude', ['plugin', 'uninstall', `${plugin}@${suffix}`], { stdio: 'pipe' });
       } catch {
         // May not be installed
       }
@@ -570,7 +591,7 @@ function copyToAgentSys() {
 
   // Install dependencies
   log('  Installing dependencies...');
-  execSync('npm install --production', { cwd: AGENTSYS_DIR, stdio: 'pipe' });
+  runCommand('npm', ['install', '--production'], { cwd: AGENTSYS_DIR, stdio: 'pipe' });
 
   agentSysCopied = true;
   log('  [OK] ~/.agentsys');
@@ -635,4 +656,4 @@ if (require.main === module) {
   main();
 }
 
-module.exports = { main };
+module.exports = { main, runCommand, commandExists };