diff --git a/scripts/headless-check.mjs b/scripts/headless-check.mjs
index 20dea77..6f7d170 100644
--- a/scripts/headless-check.mjs
+++ b/scripts/headless-check.mjs
@@ -23,6 +23,11 @@ const dist = join(root, 'dist');
 const PORT = Number(process.env.CHECK_PORT || 4176);
 const CDP_PORT = Number(process.env.CDP_PORT || 9333);
 
+if (!existsSync(join(dist, 'index.html'))) {
+  console.error('HEADLESS CHECK FAILED: dist/index.html not found. Run `npm run build` first.');
+  process.exit(1);
+}
+
 function findChrome() {
   if (process.env.CHROME) return process.env.CHROME;
   const candidates = [