diff --git a/src/index.tsx b/src/index.tsx
index 926408b19..f03746241 100644
--- a/src/index.tsx
+++ b/src/index.tsx
@@ -33,7 +33,13 @@ if ('serviceWorker' in navigator) {
     pushSessionToSW(session?.baseUrl, session?.accessToken);
   };
 
-  navigator.serviceWorker.register(swUrl).then(sendSessionToSW);
+  // The dev worker is an ES module (it imports workbox), so it must be
+  // registered as one — otherwise "script evaluation failed" and the dev
+  // client has no SW: authenticated media 401s and notification clicks
+  // never route. Production sw.js is a classic bundled script.
+  navigator.serviceWorker
+    .register(swUrl, import.meta.env.MODE === 'production' ? undefined : { type: 'module' })
+    .then(sendSessionToSW);
   navigator.serviceWorker.ready.then(sendSessionToSW);
 
   navigator.serviceWorker.addEventListener('message', (ev) => {