Index: auth.d.ts
===================================================================
--- auth.d.ts	(revision 898cf683befadffe8aea07855b58db8cd5082ff9)
+++ auth.d.ts	(revision 898cf683befadffe8aea07855b58db8cd5082ff9)
@@ -0,0 +1,15 @@
+import type { DefaultSession } from "@auth/core/types";
+
+declare module "@auth/core/types" {
+    interface User {
+        id: string;
+        isAdmin?: boolean;
+    }
+
+    interface Session {
+        user?: {
+            id: string;
+            isAdmin?: boolean;
+        } & DefaultSession["user"];
+    }
+}