diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 4ac45813c7..63491c0b30 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -40,6 +40,31 @@ jobs:
       - name: Run tests
         run: pnpm run test
 
+  # The main test job runs on Linux, where the real cmd.exe spawn tests are
+  # skipped. Run them on Windows so command quoting stays covered.
+  test-windows-spawn:
+    runs-on: windows-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: '22'
+
+      - name: Setup pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 10.12.1
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Run Windows spawn tests
+        run: pnpm exec vitest run src/__tests__/commands/setup-windows-spawn.test.ts
+
   test-binary:
     if: github.event_name == 'pull_request'
     strategy:
diff --git a/src/__tests__/commands/setup-windows-spawn.test.ts b/src/__tests__/commands/setup-windows-spawn.test.ts
new file mode 100644
index 0000000000..4b87600ccf
--- /dev/null
+++ b/src/__tests__/commands/setup-windows-spawn.test.ts
@@ -0,0 +1,58 @@
+import { describe, expect, it } from 'vitest';
+import {
+  mkdirSync,
+  mkdtempSync,
+  readFileSync,
+  rmSync,
+  writeFileSync,
+} from 'fs';
+import os from 'os';
+import path from 'path';
+import { runClientCommand } from '../../commands/setup';
+
+// Spawns a real cmd.exe, unlike setup.test.ts which mocks child_process.
+describe.runIf(process.platform === 'win32')(
+  'runClientCommand on Windows (real cmd.exe)',
+  () => {
+    it.each([
+      ['spaces and parentheses', 'Program Files (x86)'],
+      // cmd.exe expands %VAR% even inside quotes, so the path must not be
+      // rewritten to the variable's value.
+      ['a %VAR% sequence', 'dir %USERNAME% x'],
+      ['a %VAR% sequence without spaces', 'dir%USERNAME%x'],
+    ])(
+      'launches a .cmd shim under a path with %s and passes argv through exactly',
+      (_, dirName) => {
+        const root = mkdtempSync(path.join(os.tmpdir(), 'firecrawl-spawn-'));
+        const bin = path.join(root, dirName, 'nodejs');
+        const outFile = path.join(root, 'argv.json');
+        try {
+          mkdirSync(bin, { recursive: true });
+          writeFileSync(
+            path.join(bin, 'record-argv.js'),
+            'require("fs").writeFileSync(process.env.ARGV_OUT, JSON.stringify(process.argv.slice(2)));\n'
+          );
+          writeFileSync(
+            path.join(bin, 'record-argv.cmd'),
+            '@echo off\r\nnode "%~dp0record-argv.js" %*\r\n'
+          );
+          const args = [
+            '--name',
+            'firecrawl',
+            'https://mcp.firecrawl.dev/v2/mcp?a=1&b=2',
+            'Authorization: Bearer ${FIRECRAWL_API_KEY}',
+          ];
+
+          runClientCommand(path.join(bin, 'record-argv.cmd'), args, {
+            stdio: 'pipe',
+            env: { ...process.env, ARGV_OUT: outFile },
+          });
+
+          expect(JSON.parse(readFileSync(outFile, 'utf8'))).toEqual(args);
+        } finally {
+          rmSync(root, { recursive: true, force: true });
+        }
+      }
+    );
+  }
+);
diff --git a/src/__tests__/commands/setup.test.ts b/src/__tests__/commands/setup.test.ts
index 530062c681..e02947a845 100644
--- a/src/__tests__/commands/setup.test.ts
+++ b/src/__tests__/commands/setup.test.ts
@@ -886,7 +886,11 @@ describe('handleSetupCommand', () => {
       expect(command).toBe('cmd.exe');
       expect(passthruArgs.slice(0, 3)).toEqual(['/d', '/s', '/c']);
       expect(opts?.windowsVerbatimArguments).toBe(true);
-      expect(passthruArgs[3]).toContain(`^\"${path.join(bin, 'npx.CMD')}^\"`);
+      // cmd.exe parses the command token itself, so its quotes must stay real
+      // quotes: a caret-escaped ^" is a literal character there, and the path
+      // would split at the space in "Program Files".
+      expect(passthruArgs[3]).toContain(`""${path.join(bin, 'npx.CMD')}" `);
+      expect(passthruArgs[3]).not.toContain(`^\"${path.join(bin, 'npx.CMD')}`);
       expect(passthruArgs[3]).toContain('add-mcp@1.14.0');
       expect(passthruArgs[3]).toContain(
         '^"Authorization: Bearer ${FIRECRAWL_API_KEY}^"'
diff --git a/src/commands/setup.ts b/src/commands/setup.ts
index 0b444a4ee2..8e3ce6e068 100644
--- a/src/commands/setup.ts
+++ b/src/commands/setup.ts
@@ -115,6 +115,21 @@ function escapeCmdArg(arg: string): string {
   return quoted.replace(CMD_META_CHARS, '^$1');
 }
 
+/** Quote the program path that cmd.exe itself resolves. Unlike arguments, this
+ * token is parsed by cmd.exe, where a caret-escaped ^" is a literal character
+ * rather than a quote, so escaping it would split paths such as
+ * `C:\Program Files\nodejs\npx.cmd` at the space. Windows paths cannot contain
+ * `"`. cmd.exe still expands `%VAR%` (and `!VAR!` under delayed expansion)
+ * inside quotes, and a caret is literal there, so each `%`/`!` is placed
+ * outside the quotes and caret-escaped: `"C:\a"^%"X"^%"b\npx.cmd"`. */
+function quoteCmdCommand(command: string): string {
+  rejectCommandControlCharacters(command, 'Command');
+  if (command.includes('"')) {
+    throw new Error('Command path contains an unsupported quote character.');
+  }
+  return `"${command.replace(/[%!]/g, '"^$&"')}"`;
+}
+
 function windowsPathExtensions(env: NodeJS.ProcessEnv): string[] {
   const configured = env.PATHEXT ?? '.COM;.EXE;.BAT;.CMD';
   return configured
@@ -168,7 +183,7 @@ function resolveWindowsCommand(
  * On every other platform we spawn the binary directly with no shell, exactly as
  * `execFileSync` did before.
  */
-function runClientCommand(
+export function runClientCommand(
   command: string,
   args: string[],
   options: Parameters<typeof execFileSync>[2]
@@ -189,7 +204,7 @@ function runClientCommand(
     return;
   }
 
-  const line = [escapeCmdArg(resolved), ...args.map(escapeCmdArg)].join(' ');
+  const line = [quoteCmdCommand(resolved), ...args.map(escapeCmdArg)].join(' ');
   const comspec = env.ComSpec ?? env.COMSPEC ?? 'cmd.exe';
   const windowsOptions = {
     ...options,