diff --git a/launcher/mpv.test.ts b/launcher/mpv.test.ts
index a2743d5..5742343 100644
--- a/launcher/mpv.test.ts
+++ b/launcher/mpv.test.ts
@@ -5,7 +5,7 @@ import path from 'node:path';
 import net from 'node:net';
 import { EventEmitter } from 'node:events';
 import type { Args } from './types';
-import { startOverlay, state, waitForUnixSocketReady } from './mpv';
+import { runAppCommandCaptureOutput, startOverlay, state, waitForUnixSocketReady } from './mpv';
 import * as mpvModule from './mpv';
 
 function createTempSocketPath(): { dir: string; socketPath: string } {
@@ -19,6 +19,18 @@ test('mpv module exposes only canonical socket readiness helper', () => {
   assert.equal('waitForSocket' in mpvModule, false);
 });
 
+test('runAppCommandCaptureOutput captures status and stdio', () => {
+  const result = runAppCommandCaptureOutput(process.execPath, [
+    '-e',
+    'process.stdout.write("stdout-line"); process.stderr.write("stderr-line");',
+  ]);
+
+  assert.equal(result.status, 0);
+  assert.equal(result.stdout, 'stdout-line');
+  assert.equal(result.stderr, 'stderr-line');
+  assert.equal(result.error, undefined);
+});
+
 test('waitForUnixSocketReady returns false when socket never appears', async () => {
   const { dir, socketPath } = createTempSocketPath();
   try {
diff --git a/launcher/mpv.ts b/launcher/mpv.ts
index 6abd753..bdcc3eb 100644
--- a/launcher/mpv.ts
+++ b/launcher/mpv.ts
@@ -658,6 +658,28 @@ export function runAppCommandWithInherit(appPath: string, appArgs: string[]): ne
   process.exit(result.status ?? 0);
 }
 
+export function runAppCommandCaptureOutput(
+  appPath: string,
+  appArgs: string[],
+): {
+  status: number;
+  stdout: string;
+  stderr: string;
+  error?: Error;
+} {
+  const result = spawnSync(appPath, appArgs, {
+    env: buildAppEnv(),
+    encoding: 'utf8',
+  });
+
+  return {
+    status: result.status ?? 1,
+    stdout: result.stdout ?? '',
+    stderr: result.stderr ?? '',
+    error: result.error ?? undefined,
+  };
+}
+
 export function runAppCommandWithInheritLogged(
   appPath: string,
   appArgs: string[],