diff --git a/lib/use-card-detail.js b/lib/use-card-detail.js
index a2c072f..b500524 100644
--- a/lib/use-card-detail.js
+++ b/lib/use-card-detail.js
@@ -5,7 +5,7 @@ import { VOCAB, collectionDisplayName } from './collection-vocabulary.js';
 /**
  * Card/collection page state and handlers (god-component split).
  */
-export function useCardDetail({ user, authLoading }) {
+export function useCardDetail({ user = null, authLoading = true } = {}) {
   const router = useRouter();
   const isAdmin = user?.role === 'admin';
   const adminLoading = authLoading;
diff --git a/pages/card/[id].js b/pages/card/[id].js
index bfe4fca..b4d08d6 100644
--- a/pages/card/[id].js
+++ b/pages/card/[id].js
@@ -6,8 +6,8 @@ import { useCardDetail } from '../../lib/use-card-detail.js';
 
 export default function CardDetail() {
   const router = useRouter();
-  const { user } = useAuth();
-  const detail = useCardDetail();
+  const { user, loading: authLoading } = useAuth();
+  const detail = useCardDetail({ user, authLoading });
 
   if (detail.loading) {
     return (