diff --git a/.prettierignore b/.prettierignore
index 32405c6..5380627 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -2,3 +2,4 @@ pnpm-lock.yaml
 dist/
 node_modules/
 CHANGELOG.md
+CLAUDE.md
diff --git a/README.md b/README.md
index 93cb8ac..d66ccb7 100644
--- a/README.md
+++ b/README.md
@@ -100,6 +100,14 @@ Telemetry is automatically disabled in CI environments and during development.
 
 ## Development
 
+On Windows, clone with symlinks enabled so `CLAUDE.md` is not checked out as a copy (which breaks Prettier):
+
+```bash
+git clone -c core.symlinks=true https://github.com/spotify/confidence-cli.git
+```
+
+If the repo is already cloned, run `git checkout -- CLAUDE.md` after `git config core.symlinks true`.
+
 ```bash
 pnpm install
 pnpm try          # Run the wizard locally via tsx
diff --git a/__tests__/e2e/system-check-failure.e2e.ts b/__tests__/e2e/system-check-failure.e2e.ts
index 9defccf..496a872 100644
--- a/__tests__/e2e/system-check-failure.e2e.ts
+++ b/__tests__/e2e/system-check-failure.e2e.ts
@@ -1,5 +1,6 @@
-import { createSession } from './testing-framework/index.js';
 import { dirname } from 'node:path';
+import { isWindows } from '../shared/platform.js';
+import { createSession } from './testing-framework/index.js';
 
 describe('when system check fails', () => {
   it('shows error when git is missing', async () => {
@@ -18,8 +19,13 @@ describe('when system check fails', () => {
     expect(session.snapshot()).toMatchSnapshot('system-check-failure');
   });
 
-  it('shows error when node is not on PATH', async () => {
-    // PATH with git but not node — CLI still runs via absolute path
+  /**
+   * @todo Make this test work on Windows. It currently relies on `/usr/bin`
+   * as a PATH that contains git but not node, which has no direct Windows
+   * equivalent. Constructing one portably is non-trivial because git's
+   * install location varies across Windows setups.
+   */
+  it.skipIf(isWindows)('shows error when node is not on PATH', async () => {
     using session = createSession({ systemPath: '/usr/bin' });
 
     await session.waitForText('Start setup');
diff --git a/__tests__/e2e/testing-framework/mocks/binaries/fs.ts b/__tests__/e2e/testing-framework/mocks/binaries/fs.ts
new file mode 100644
index 0000000..14f7f0f
--- /dev/null
+++ b/__tests__/e2e/testing-framework/mocks/binaries/fs.ts
@@ -0,0 +1,23 @@
+import { writeFileSync, chmodSync } from 'node:fs';
+import { join } from 'node:path';
+import { isWindows } from '../../../../shared/platform.js';
+
+export const writeMockBinary = isWindows ? writeWindowsBinary : writeUnixBinary;
+
+function writeUnixBinary(dir: string, name: string, script: string): void {
+  const filePath = join(dir, name);
+  writeFileSync(filePath, script, 'utf-8');
+  chmodSync(filePath, 0o755);
+}
+
+function writeWindowsBinary(dir: string, name: string, script: string): void {
+  const jsPath = join(dir, `${name}.js`);
+  writeFileSync(jsPath, script.replace(/^#!.*\n/, ''), 'utf-8');
+  // `.cmd` is for cmd.exe; CreateProcess cannot run it. The CLI resolves
+  // `{name}.js` on PATH and runs it with Node instead (`resolveBin`).
+  writeFileSync(join(dir, `${name}.cmd`), `@node "%~dp0${name}.js" %*\r\n`, 'utf-8');
+}
+
+export const writeMockOpenStub = isWindows
+  ? (dir: string) => writeFileSync(join(dir, 'open.cmd'), '@exit /b 0\r\n', 'utf-8')
+  : (dir: string) => writeUnixBinary(dir, 'open', '#!/bin/sh\nexit 0\n');
diff --git a/__tests__/e2e/testing-framework/mocks/binaries/index.ts b/__tests__/e2e/testing-framework/mocks/binaries/index.ts
index 0a6a082..34be236 100644
--- a/__tests__/e2e/testing-framework/mocks/binaries/index.ts
+++ b/__tests__/e2e/testing-framework/mocks/binaries/index.ts
@@ -1,8 +1,9 @@
-import { writeFileSync, mkdirSync, chmodSync } from 'node:fs';
+import { mkdirSync } from 'node:fs';
 import { join } from 'node:path';
 import { CLAUDE_SCRIPT } from './claude.js';
 import { CURSOR_SCRIPT } from './cursor.js';
 import { CODEX_SCRIPT } from './codex.js';
+import { writeMockBinary, writeMockOpenStub } from './fs.js';
 
 /** Filename the mock IDE binary writes the chat prompt to. */
 export const CHAT_PROMPT_FILE = '.e2e-chat-prompt';
@@ -10,12 +11,6 @@ export const CHAT_PROMPT_FILE = '.e2e-chat-prompt';
 /** Filename the mock IDE binary writes the onboarding invocation JSON to. */
 export const ONBOARDING_INVOCATION_FILE = '.e2e-onboarding-invocation';
 
-function writeMockBinary(dir: string, name: string, script: string): void {
-  const filePath = join(dir, name);
-  writeFileSync(filePath, script, 'utf-8');
-  chmodSync(filePath, 0o755);
-}
-
 /**
  * Creates a directory of executable mock IDE binaries (`claude`, `cursor`,
  * `codex`, `open`) that the wizard will find on `PATH` during e2e tests.
@@ -34,7 +29,8 @@ export function createMockBinDir(dir: string): string {
   writeMockBinary(binDir, 'claude', CLAUDE_SCRIPT);
   writeMockBinary(binDir, 'cursor', CURSOR_SCRIPT);
   writeMockBinary(binDir, 'codex', CODEX_SCRIPT);
-  writeMockBinary(binDir, 'open', '#!/bin/sh\nexit 0\n');
+
+  writeMockOpenStub(binDir);
 
   return binDir;
 }
diff --git a/__tests__/e2e/testing-framework/session-factory.ts b/__tests__/e2e/testing-framework/session-factory.ts
index d2c706f..e91af91 100644
--- a/__tests__/e2e/testing-framework/session-factory.ts
+++ b/__tests__/e2e/testing-framework/session-factory.ts
@@ -1,6 +1,6 @@
 import { mkdtempSync, writeFileSync } from 'node:fs';
-import { join } from 'node:path';
 import { tmpdir } from 'node:os';
+import { delimiter, join } from 'node:path';
 import { TerminalSession } from './terminal/index.js';
 import { createProjectDir, type ProjectType } from '../../shared/project-scaffold/index.js';
 
@@ -56,7 +56,7 @@ export function createSession({
   const { path: projectDir } = createProjectDir(project);
 
   const sessionEnv: Record<string, string> = {
-    PATH: `${mockBinDir}:${systemPath ?? process.env.PATH}`,
+    PATH: `${mockBinDir}${delimiter}${systemPath ?? process.env.PATH}`,
     ...env,
   };
 
diff --git a/__tests__/e2e/testing-framework/terminal/session.ts b/__tests__/e2e/testing-framework/terminal/session.ts
index 50d12fa..60caea6 100644
--- a/__tests__/e2e/testing-framework/terminal/session.ts
+++ b/__tests__/e2e/testing-framework/terminal/session.ts
@@ -6,6 +6,8 @@ import { join } from 'node:path';
 import { stripAnsi } from './strip-ansi.js';
 import { renderScreen, normalizeSnapshot } from './screen-buffer.js';
 import { E2E_BASE_ENV } from '../env.js';
+import { overlayEnv } from '../../../shared/overlay-env.js';
+import { isWindows } from '../../../shared/platform.js';
 import { resolveKey, type Modifiers } from '../../../shared/key-map.js';
 
 const CLI_PATH = resolve(import.meta.dirname, '../../../../dist/bin/cli.js');
@@ -81,13 +83,13 @@ export class TerminalSession {
       cols,
       rows,
       cwd: this.cwd,
-      env: {
-        ...process.env,
-        ...E2E_BASE_ENV,
-        ...env,
+      env: overlayEnv(process.env, E2E_BASE_ENV, env, {
         HOME: isolatedTmpDir,
         TMPDIR: isolatedTmpDir,
-      },
+        ...(isWindows
+          ? { USERPROFILE: isolatedTmpDir, TEMP: isolatedTmpDir, TMP: isolatedTmpDir }
+          : {}),
+      }),
     });
 
     this.pty.onData((data) => {
diff --git a/__tests__/integrations/prepare.test.ts b/__tests__/integrations/prepare.test.ts
index df6300a..eafda0e 100644
--- a/__tests__/integrations/prepare.test.ts
+++ b/__tests__/integrations/prepare.test.ts
@@ -2,24 +2,8 @@ import { vi } from 'vitest';
 
 const execFile = vi.fn();
 
-vi.mock('node:child_process', () => ({
-  execFile: (
-    _cmd: string,
-    _args: string[],
-    cb: (err: Error | null, stdout?: string, stderr?: string) => void,
-  ) => {
-    const result = execFile(_cmd, _args) as Promise<{ stdout: string }>;
-    result.then(
-      (val) => cb(null, val.stdout, ''),
-      (err: Error) => cb(err),
-    );
-    return {};
-  },
-}));
-
-vi.mock('node:util', () => ({
-  promisify: () => (cmd: string, args: string[]) =>
-    execFile(cmd, args) as Promise<{ stdout: string }>,
+vi.mock('@lib/exec.js', () => ({
+  execFile: (cmd: string, args: string[]) => execFile(cmd, args) as Promise<{ stdout: string }>,
 }));
 
 beforeEach(() => {
diff --git a/__tests__/lib/resolve-bin.test.ts b/__tests__/lib/resolve-bin.test.ts
new file mode 100644
index 0000000..f10fb43
--- /dev/null
+++ b/__tests__/lib/resolve-bin.test.ts
@@ -0,0 +1,41 @@
+import { join } from 'node:path';
+import { resolveBin } from '@lib/resolve-bin.js';
+
+describe('resolveBin', () => {
+  it('returns the command unchanged on Unix even when a .js shim exists', () => {
+    const sut = resolveBin('claude', ['--version'], {
+      platform: 'darwin',
+      pathEnv: '/mock/bin',
+      exists: () => true,
+    });
+
+    expect(sut).toEqual({ command: 'claude', args: ['--version'] });
+  });
+
+  it('runs a PATH .js shim with node on Windows', () => {
+    const binDir = '/mock/bin';
+    const jsPath = join(binDir, 'claude.js');
+
+    const sut = resolveBin('claude', ['--version'], {
+      platform: 'win32',
+      pathEnv: binDir,
+      execPath: '/nodejs/node.exe',
+      exists: (path) => path === jsPath,
+    });
+
+    expect(sut).toEqual({
+      command: '/nodejs/node.exe',
+      args: [jsPath, '--version'],
+    });
+  });
+
+  it('returns the command unchanged on Windows when no .js shim exists', () => {
+    const sut = resolveBin('claude', ['--version'], {
+      platform: 'win32',
+      pathEnv: join('/Windows', 'System32'),
+      exists: () => false,
+    });
+
+    expect(sut).toEqual({ command: 'claude', args: ['--version'] });
+  });
+});
diff --git a/__tests__/shared/overlay-env.test.ts b/__tests__/shared/overlay-env.test.ts
new file mode 100644
index 0000000..a82c3a1
--- /dev/null
+++ b/__tests__/shared/overlay-env.test.ts
@@ -0,0 +1,26 @@
+import { overlayEnv } from './overlay-env.js';
+
+describe('overlayEnv', () => {
+  it('replaces Windows Path with PATH so mock bins win', () => {
+    const sut = overlayEnv(
+      { Path: 'C:\\Windows', HOME: '/old' },
+      { PATH: 'C:\\mock\\bin', HOME: '/tmp/e2e' },
+    );
+
+    expect(sut.PATH).toBe('C:\\mock\\bin');
+    expect(sut.Path).toBeUndefined();
+    expect(sut.HOME).toBe('/tmp/e2e');
+  });
+
+  it('replaces Temp and Tmp when TEMP and TMP are set', () => {
+    const sut = overlayEnv(
+      { Temp: 'C:\\Windows\\Temp', Tmp: 'C:\\Windows\\Temp' },
+      { TEMP: 'D:\\e2e', TMP: 'D:\\e2e' },
+    );
+
+    expect(sut.TEMP).toBe('D:\\e2e');
+    expect(sut.TMP).toBe('D:\\e2e');
+    expect(sut.Temp).toBeUndefined();
+    expect(sut.Tmp).toBeUndefined();
+  });
+});
diff --git a/__tests__/shared/overlay-env.ts b/__tests__/shared/overlay-env.ts
new file mode 100644
index 0000000..1aa2568
--- /dev/null
+++ b/__tests__/shared/overlay-env.ts
@@ -0,0 +1,29 @@
+/**
+ * Merges environment layers, replacing keys that differ only by case.
+ *
+ * Spreading `process.env` on Windows leaves `Path` / `Temp` alongside later
+ * `PATH` / `TEMP` entries. Child processes can then keep the host values.
+ */
+export function overlayEnv(
+  ...layers: Array<NodeJS.Dict<string | undefined>>
+): Record<string, string> {
+  const result: Record<string, string> = {};
+  const keyByLower = new Map<string, string>();
+
+  for (const layer of layers) {
+    for (const [key, value] of Object.entries(layer)) {
+      if (value === undefined) continue;
+
+      const lower = key.toLowerCase();
+      const previousKey = keyByLower.get(lower);
+      if (previousKey !== undefined && previousKey !== key) {
+        delete result[previousKey];
+      }
+
+      result[key] = value;
+      keyByLower.set(lower, key);
+    }
+  }
+
+  return result;
+}
diff --git a/__tests__/shared/platform.ts b/__tests__/shared/platform.ts
new file mode 100644
index 0000000..7dbb967
--- /dev/null
+++ b/__tests__/shared/platform.ts
@@ -0,0 +1,5 @@
+export const isWindows = process.platform === 'win32';
+
+export function perPlatform<T>(options: { windows: T; unix: T }): T {
+  return isWindows ? options.windows : options.unix;
+}
diff --git a/__tests__/shared/project-scaffold/index.ts b/__tests__/shared/project-scaffold/index.ts
index a170981..4bed870 100644
--- a/__tests__/shared/project-scaffold/index.ts
+++ b/__tests__/shared/project-scaffold/index.ts
@@ -1,4 +1,7 @@
 import { mkdtempSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { perPlatform } from '../platform.js';
 import { SCAFFOLDS } from './scaffolds.js';
 import type { ProjectType } from './types.js';
 
@@ -9,10 +12,15 @@ export type { ProjectType };
  * project scaffold. Supports `Symbol.dispose` for automatic cleanup.
  *
  * @remarks
- * Uses a hardcoded `/tmp/` prefix instead of `os.tmpdir()`. On macOS
- * `tmpdir()` returns `/var/folders/…` which is longer than Linux's `/tmp/`,
- * shifting column alignment in the VT100 screen buffer and breaking e2e
- * snapshot assertions across platforms.
+ * Uses `/tmp/` on Unix instead of `os.tmpdir()`. On macOS `tmpdir()`
+ * returns `/var/folders/…` which is longer than Linux's `/tmp/`, shifting
+ * column alignment in the VT100 screen buffer and breaking e2e snapshot
+ * assertions across platforms. On Windows, `/tmp/` doesn't exist so we
+ * fall back to `os.tmpdir()`.
+ *
+ * @todo The Windows `tmpdir()` path is longer than `/tmp/`, producing
+ * different VT100 column alignment and incompatible e2e snapshots. When
+ * Windows CI is added, use a fixed-length prefix on all platforms.
  *
  * @param type - A named scaffold, or `null` for an empty directory.
  *   @defaultValue `'react'`
@@ -26,7 +34,12 @@ export type { ProjectType };
  * ```
  */
 export function createProjectDir(type: ProjectType = 'react') {
-  const dir = mkdtempSync('/tmp/wizard-test-');
+  const prefix = perPlatform({
+    windows: join(tmpdir(), 'wizard-test-'),
+    unix: '/tmp/wizard-test-',
+  });
+
+  const dir = mkdtempSync(prefix);
   SCAFFOLDS[type](dir);
 
   return {
diff --git a/src/integrations/claude/chat.ts b/src/integrations/claude/chat.ts
index d7103ed..060bf25 100644
--- a/src/integrations/claude/chat.ts
+++ b/src/integrations/claude/chat.ts
@@ -1,4 +1,4 @@
-import { spawn } from 'node:child_process';
+import { spawn } from '@lib/exec.js';
 import type { ChatOpts } from '../types.js';
 
 export function launchChat({ prompt, cwd }: ChatOpts): void {
diff --git a/src/integrations/claude/mcp.ts b/src/integrations/claude/mcp.ts
index 4d25f2d..3c7e474 100644
--- a/src/integrations/claude/mcp.ts
+++ b/src/integrations/claude/mcp.ts
@@ -1,7 +1,6 @@
-import { execFile as execFileCb } from 'node:child_process';
-import { promisify } from 'node:util';
 import { existsSync, readFileSync, writeFileSync, mkdirSync } from 'node:fs';
 import { join } from 'node:path';
+import { execFile } from '@lib/exec.js';
 import type { McpConnectOpts } from '../types.js';
 import {
   type McpServerName,
@@ -11,8 +10,6 @@ import {
 import { getRegisteredMcpNames, getStoredAuthToken } from '../mcp/config.js';
 import { projectConfigPath } from './paths.js';
 
-const execFile = promisify(execFileCb);
-
 export function detectMcpStatuses(
   projectDir: string,
 ): Promise<Record<McpServerName, McpServerStatus>> {
diff --git a/src/integrations/claude/onboarding.ts b/src/integrations/claude/onboarding.ts
index 6878ca5..82cbe0b 100644
--- a/src/integrations/claude/onboarding.ts
+++ b/src/integrations/claude/onboarding.ts
@@ -1,5 +1,6 @@
-import { type ChildProcess, spawn } from 'node:child_process';
+import type { ChildProcess } from 'node:child_process';
 import { createInterface } from 'node:readline';
+import { spawn } from '@lib/exec.js';
 import type { OnboardingOpts, OnboardingCallbacks } from '../types.js';
 import { ONBOARDING_TIMEOUT_MS } from '../constants.js';
 import { type StreamEvent, extractTextLines } from '../stream-json.js';
diff --git a/src/integrations/claude/plugins.ts b/src/integrations/claude/plugins.ts
index f182bb9..4ea09d1 100644
--- a/src/integrations/claude/plugins.ts
+++ b/src/integrations/claude/plugins.ts
@@ -1,13 +1,10 @@
-import { execFile as execFileCb } from 'node:child_process';
 import { resolve } from 'node:path';
-import { promisify } from 'node:util';
+import { execFile } from '@lib/exec.js';
 import { PLUGIN_NAME } from '@lib/constants.js';
 import type { PluginInstallationMethod } from '@shared-kernel/types.js';
 import { hasDownloadedSkills } from '../skills/local.js';
 import { skillsDir } from './paths.js';
 
-const execFile = promisify(execFileCb);
-
 type PluginEntry = {
   id: string;
   enabled: boolean;
diff --git a/src/integrations/claude/prepare.ts b/src/integrations/claude/prepare.ts
index 48acecf..1a60609 100644
--- a/src/integrations/claude/prepare.ts
+++ b/src/integrations/claude/prepare.ts
@@ -1,9 +1,6 @@
-import { execFile as execFileCb } from 'node:child_process';
-import { promisify } from 'node:util';
+import { execFile } from '@lib/exec.js';
 import { extractVersion, isAtLeast } from '../version.js';
 
-const execFile = promisify(execFileCb);
-
 const MIN_VERSION = [2, 1, 212];
 
 export async function prepare(): Promise<void> {
diff --git a/src/integrations/codex/chat.ts b/src/integrations/codex/chat.ts
index f3298de..3013e9c 100644
--- a/src/integrations/codex/chat.ts
+++ b/src/integrations/codex/chat.ts
@@ -1,4 +1,4 @@
-import { spawn } from 'node:child_process';
+import { spawn } from '@lib/exec.js';
 import type { ChatOpts } from '../types.js';
 
 export function launchChat({ prompt, cwd, token }: ChatOpts): void {
diff --git a/src/integrations/codex/mcp.ts b/src/integrations/codex/mcp.ts
index 0b8471c..1be8d9f 100644
--- a/src/integrations/codex/mcp.ts
+++ b/src/integrations/codex/mcp.ts
@@ -1,6 +1,5 @@
 import { readFileSync, writeFileSync } from 'node:fs';
-import { execFile as execFileCb } from 'node:child_process';
-import { promisify } from 'node:util';
+import { execFile } from '@lib/exec.js';
 import type { McpConnectOpts } from '../types.js';
 import {
   MCP_SERVERS,
@@ -10,8 +9,6 @@ import {
 } from '../mcp/servers.js';
 import { globalConfigPath, projectConfigPath } from './paths.js';
 
-const execFile = promisify(execFileCb);
-
 export function detectMcpStatuses(
   projectDir: string,
 ): Promise<Record<McpServerName, McpServerStatus>> {
diff --git a/src/integrations/codex/onboarding.ts b/src/integrations/codex/onboarding.ts
index 77c108f..dc7bd25 100644
--- a/src/integrations/codex/onboarding.ts
+++ b/src/integrations/codex/onboarding.ts
@@ -1,5 +1,6 @@
-import { type ChildProcess, spawn } from 'node:child_process';
+import type { ChildProcess } from 'node:child_process';
 import { createInterface } from 'node:readline';
+import { spawn } from '@lib/exec.js';
 import type { OnboardingOpts, OnboardingCallbacks } from '../types.js';
 import { ONBOARDING_TIMEOUT_MS } from '../constants.js';
 import {
diff --git a/src/integrations/codex/plugins.ts b/src/integrations/codex/plugins.ts
index e684be8..eca8855 100644
--- a/src/integrations/codex/plugins.ts
+++ b/src/integrations/codex/plugins.ts
@@ -1,12 +1,9 @@
-import { execFile as execFileCb } from 'node:child_process';
-import { promisify } from 'node:util';
+import { execFile } from '@lib/exec.js';
 import { PLUGIN_MARKETPLACE_REPO, PLUGIN_MARKETPLACE_NAME, PLUGIN_NAME } from '@lib/constants.js';
 import type { PluginInstallationMethod } from '@shared-kernel/types.js';
 import { hasDownloadedSkills } from '../skills/local.js';
 import { skillsDir } from './paths.js';
 
-const execFile = promisify(execFileCb);
-
 export async function detectPlugin(projectDir: string): Promise<PluginInstallationMethod | null> {
   try {
     const cwd = projectDir;
diff --git a/src/integrations/codex/prepare.ts b/src/integrations/codex/prepare.ts
index 0277d64..de0b862 100644
--- a/src/integrations/codex/prepare.ts
+++ b/src/integrations/codex/prepare.ts
@@ -1,9 +1,6 @@
-import { execFile as execFileCb } from 'node:child_process';
-import { promisify } from 'node:util';
+import { execFile } from '@lib/exec.js';
 import { extractVersion, isAtLeast } from '../version.js';
 
-const execFile = promisify(execFileCb);
-
 const MIN_VERSION = [0, 146, 0];
 
 export async function prepare(): Promise<void> {
diff --git a/src/integrations/cursor/chat.ts b/src/integrations/cursor/chat.ts
index c5802ed..d0f7251 100644
--- a/src/integrations/cursor/chat.ts
+++ b/src/integrations/cursor/chat.ts
@@ -1,4 +1,4 @@
-import { spawn } from 'node:child_process';
+import { spawn } from '@lib/exec.js';
 import type { ChatOpts } from '../types.js';
 
 export function launchChat({ prompt, cwd, token }: ChatOpts): void {
diff --git a/src/integrations/cursor/mcp.ts b/src/integrations/cursor/mcp.ts
index eb2e995..a9a5b40 100644
--- a/src/integrations/cursor/mcp.ts
+++ b/src/integrations/cursor/mcp.ts
@@ -1,7 +1,6 @@
 import { existsSync, readFileSync, writeFileSync, mkdirSync } from 'node:fs';
-import { execFile as execFileCb } from 'node:child_process';
 import { join } from 'node:path';
-import { promisify } from 'node:util';
+import { execFile } from '@lib/exec.js';
 import type { McpConnectOpts } from '../types.js';
 import {
   type McpServerName,
@@ -11,8 +10,6 @@ import {
 import { getRegisteredMcpNames, getStoredAuthToken } from '../mcp/config.js';
 import { cliConfigPath, globalConfigPath, mcpConfigPath } from './paths.js';
 
-const execFile = promisify(execFileCb);
-
 export function detectMcpStatuses(
   projectDir: string,
 ): Promise<Record<McpServerName, McpServerStatus>> {
diff --git a/src/integrations/cursor/onboarding.ts b/src/integrations/cursor/onboarding.ts
index df56c47..a2b283f 100644
--- a/src/integrations/cursor/onboarding.ts
+++ b/src/integrations/cursor/onboarding.ts
@@ -1,5 +1,6 @@
-import { type ChildProcess, spawn } from 'node:child_process';
+import type { ChildProcess } from 'node:child_process';
 import { createInterface } from 'node:readline';
+import { spawn } from '@lib/exec.js';
 import type { OnboardingOpts, OnboardingCallbacks } from '../types.js';
 import { ONBOARDING_TIMEOUT_MS } from '../constants.js';
 import { type StreamEvent, extractTextLines } from '../stream-json.js';
diff --git a/src/integrations/cursor/plugins.ts b/src/integrations/cursor/plugins.ts
index c695fca..d738287 100644
--- a/src/integrations/cursor/plugins.ts
+++ b/src/integrations/cursor/plugins.ts
@@ -1,12 +1,9 @@
-import { execFile as execFileCb } from 'node:child_process';
-import { promisify } from 'node:util';
+import { execFile } from '@lib/exec.js';
 import { PLUGIN_REPO_URL } from '@lib/constants.js';
 import type { PluginInstallationMethod } from '@shared-kernel/types.js';
 import { hasDownloadedSkills } from '../skills/local.js';
 import { skillsDir } from './paths.js';
 
-const execFile = promisify(execFileCb);
-
 export async function detectPlugin(projectDir: string): Promise<PluginInstallationMethod | null> {
   return hasDownloadedSkills(skillsDir(projectDir)) ? 'download' : null;
 }
diff --git a/src/integrations/cursor/prepare.ts b/src/integrations/cursor/prepare.ts
index 50ef171..217bcbc 100644
--- a/src/integrations/cursor/prepare.ts
+++ b/src/integrations/cursor/prepare.ts
@@ -1,9 +1,6 @@
-import { execFile as execFileCb } from 'node:child_process';
-import { promisify } from 'node:util';
+import { execFile } from '@lib/exec.js';
 import { extractVersion, isAtLeast } from '../version.js';
 
-const execFile = promisify(execFileCb);
-
 const MIN_VERSION = [3, 19, 7];
 
 export async function prepare(): Promise<void> {
diff --git a/src/lib/exec.ts b/src/lib/exec.ts
new file mode 100644
index 0000000..f9c868d
--- /dev/null
+++ b/src/lib/exec.ts
@@ -0,0 +1,43 @@
+import {
+  execFile as cpExecFile,
+  spawn as cpSpawn,
+  type ChildProcess,
+  type ExecFileOptions,
+  type SpawnOptions,
+} from 'node:child_process';
+import { promisify } from 'node:util';
+import { pathFromEnv, resolveBin } from './resolve-bin.js';
+
+const promisifiedExecFile = promisify(cpExecFile);
+
+/**
+ * `spawn` that runs Windows `.js` PATH shims with Node instead of `.cmd` files.
+ *
+ * @see {@link resolveBin}
+ */
+export function spawn(
+  command: string,
+  args: readonly string[],
+  options?: SpawnOptions,
+): ChildProcess {
+  const resolved = resolveBin(command, args, { pathEnv: pathFromEnv(options?.env) });
+  return cpSpawn(resolved.command, resolved.args, options ?? {});
+}
+
+/**
+ * `execFile` that runs Windows `.js` PATH shims with Node instead of `.cmd` files.
+ *
+ * @see {@link resolveBin}
+ */
+export async function execFile(
+  command: string,
+  args: readonly string[],
+  options?: ExecFileOptions,
+): Promise<{ stdout: string; stderr: string }> {
+  const resolved = resolveBin(command, args, { pathEnv: pathFromEnv(options?.env) });
+  const { stdout, stderr } = await promisifiedExecFile(resolved.command, resolved.args, {
+    ...options,
+    encoding: 'utf8',
+  });
+  return { stdout, stderr };
+}
diff --git a/src/lib/resolve-bin.ts b/src/lib/resolve-bin.ts
new file mode 100644
index 0000000..a104759
--- /dev/null
+++ b/src/lib/resolve-bin.ts
@@ -0,0 +1,46 @@
+import { existsSync } from 'node:fs';
+import { delimiter, join } from 'node:path';
+
+type ResolveBinOptions = {
+  /** Override `process.platform` (tests). @defaultValue `process.platform` */
+  platform?: NodeJS.Platform;
+  /** PATH to search for a `.js` shim. @defaultValue `process.env.PATH` */
+  pathEnv?: string;
+  /** Node executable used to run a `.js` shim. @defaultValue `process.execPath` */
+  execPath?: string;
+  /** Override filesystem lookup (tests). @defaultValue `existsSync` */
+  exists?: (path: string) => boolean;
+};
+
+/**
+ * Resolves a command so `execFile`/`spawn` can run it without a shell.
+ *
+ * On Windows, `CreateProcess` cannot execute `.cmd` shims. If `{command}.js`
+ * exists on PATH (the e2e mock layout), run it with Node instead so flags
+ * like `--version` are passed to the script rather than to Node itself.
+ */
+export function resolveBin(
+  command: string,
+  args: readonly string[],
+  options: ResolveBinOptions = {},
+): { command: string; args: string[] } {
+  const platform = options.platform ?? process.platform;
+  if (platform !== 'win32') return { command, args: [...args] };
+
+  const pathEnv = options.pathEnv ?? process.env.PATH ?? process.env.Path ?? '';
+  const exists = options.exists ?? existsSync;
+  const execPath = options.execPath ?? process.execPath;
+
+  for (const dir of pathEnv.split(delimiter)) {
+    if (!dir) continue;
+    const jsPath = join(dir, `${command}.js`);
+    if (exists(jsPath)) return { command: execPath, args: [jsPath, ...args] };
+  }
+
+  return { command, args: [...args] };
+}
+
+export function pathFromEnv(env?: NodeJS.ProcessEnv): string | undefined {
+  if (!env) return undefined;
+  return env.PATH ?? env.Path ?? env.path;
+}
diff --git a/vitest.config.e2e.ts b/vitest.config.e2e.ts
index 0481f0b..393a2b6 100644
--- a/vitest.config.e2e.ts
+++ b/vitest.config.e2e.ts
@@ -1,14 +1,15 @@
+import { fileURLToPath } from 'node:url';
 import { defineConfig } from 'vitest/config';
 
 export default defineConfig({
   resolve: {
     alias: {
-      '@commands': new URL('./src/commands', import.meta.url).pathname,
-      '@frameworks': new URL('./src/frameworks', import.meta.url).pathname,
-      '@integrations': new URL('./src/integrations', import.meta.url).pathname,
-      '@providers': new URL('./src/providers', import.meta.url).pathname,
-      '@ui': new URL('./src/ui', import.meta.url).pathname,
-      '@lib': new URL('./src/lib', import.meta.url).pathname,
+      '@commands': fileURLToPath(new URL('./src/commands', import.meta.url)),
+      '@frameworks': fileURLToPath(new URL('./src/frameworks', import.meta.url)),
+      '@integrations': fileURLToPath(new URL('./src/integrations', import.meta.url)),
+      '@providers': fileURLToPath(new URL('./src/providers', import.meta.url)),
+      '@ui': fileURLToPath(new URL('./src/ui', import.meta.url)),
+      '@lib': fileURLToPath(new URL('./src/lib', import.meta.url)),
     },
   },
   test: {
diff --git a/vitest.config.ts b/vitest.config.ts
index 7369bcf..338847d 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -1,3 +1,4 @@
+import { fileURLToPath } from 'node:url';
 import { defineConfig } from 'vitest/config';
 
 const isCI = !!process.env.CI;
@@ -5,14 +6,14 @@ const isCI = !!process.env.CI;
 export default defineConfig({
   resolve: {
     alias: {
-      '@commands': new URL('./src/commands', import.meta.url).pathname,
-      '@features': new URL('./src/features', import.meta.url).pathname,
-      '@frameworks': new URL('./src/frameworks', import.meta.url).pathname,
-      '@integrations': new URL('./src/integrations', import.meta.url).pathname,
-      '@providers': new URL('./src/providers', import.meta.url).pathname,
-      '@shared-kernel': new URL('./src/shared-kernel', import.meta.url).pathname,
-      '@ui': new URL('./src/ui', import.meta.url).pathname,
-      '@lib': new URL('./src/lib', import.meta.url).pathname,
+      '@commands': fileURLToPath(new URL('./src/commands', import.meta.url)),
+      '@features': fileURLToPath(new URL('./src/features', import.meta.url)),
+      '@frameworks': fileURLToPath(new URL('./src/frameworks', import.meta.url)),
+      '@integrations': fileURLToPath(new URL('./src/integrations', import.meta.url)),
+      '@providers': fileURLToPath(new URL('./src/providers', import.meta.url)),
+      '@shared-kernel': fileURLToPath(new URL('./src/shared-kernel', import.meta.url)),
+      '@ui': fileURLToPath(new URL('./src/ui', import.meta.url)),
+      '@lib': fileURLToPath(new URL('./src/lib', import.meta.url)),
     },
   },
   test: {