diff --git a/frontend/README.md b/frontend/README.md
index e215bc4..659f484 100644
--- a/frontend/README.md
+++ b/frontend/README.md
@@ -34,3 +34,25 @@ You can check out [the Next.js GitHub repository](https://github.com/vercel/next
 The easiest way to deploy your Next.js app is to use the [Vercel Platform](https://vercel.com/new?utm_medium=default-template&filter=next.js&utm_source=create-next-app&utm_campaign=create-next-app-readme) from the creators of Next.js.
 
 Check out our [Next.js deployment documentation](https://nextjs.org/docs/app/building-your-application/deploying) for more details.
+## Auth-Architektur (Grundlagen)
+
+### Prinzipien
+- Guard-first Architektur
+- Keine Auth-Logik in Services
+- Controller bleiben dünn
+- Zentrale User-Wahrheit über Request-Kontext
+
+### RequestUser
+- `req.user` ist der einzige User-Kontext im Request
+- Typ: `RequestUser`
+- ID ist **number** (DB-kompatibel)
+- Kann `null` sein (Public Routes)
+
+```ts
+export type UserRole = 'USER' | 'ADMIN' | 'MOD';
+
+export type RequestUser = {
+  id: number;
+  role: UserRole;
+  isFake?: boolean;
+} | null;