diff --git a/frontend/src/app.d.ts b/frontend/src/app.d.ts
index 6057acbc..82a7a981 100644
--- a/frontend/src/app.d.ts
+++ b/frontend/src/app.d.ts
@@ -26,6 +26,11 @@ declare global {
 		interface PageData {
 			user?: User; // Available in $page.data.user
 		}
+
+		interface Error {
+			message: string;
+			errorId?: string;
+		}
 	}
 }