Clerk Auth

---
name: clerk-auth
description: "Expert patterns for Clerk auth implementation, middleware, organizations, webhooks, and user sync Use when: adding authentication, clerk auth, user authentication, sign in, sign up."
source: rootcastle-rei
risk: unknown
---

# Clerk Authentication

## Patterns

### Next.js App Router Setup

Complete Clerk setup for Next.js 14/15 App Router.

Includes ClerkProvider, environment variables, and basic
sign-in/sign-up components.

Key components:
- ClerkProvider: Wraps app for auth context
- <SignIn />, <SignUp />: Pre-built auth forms
- <UserButton />: User menu with session management


### Middleware Route Protection

Protect routes using clerkMiddleware and createRouteMatcher.

Best practices:
- Single middleware.ts file at project root
- Use createRouteMatcher for route groups
- auth.protect() for explicit protection
- Centralize all auth logic in middleware


### Server Component Authentication

Access auth state in Server Components using auth() and currentUser().

Key functions:
- auth(): Returns userId, sessionId, orgId, claims
- currentUser(): Returns full User object
- Both require clerkMiddleware to be configured


## ⚠️ Sharp Edges

| Issue | Severity | Solution |
|-------|----------|----------|
| Issue | critical | See docs |
| Issue | high | See docs |
| Issue | high | See docs |
| Issue | high | See docs |
| Issue | medium | See docs |
| Issue | medium | See docs |
| Issue | medium | See docs |
| Issue | medium | See docs |

## When to Use
This skill is applicable to execute the workflow or actions described in the overview.

---

> 🏰 **Rei Skills** — Curated by [Rootcastle Engineering & Innovation](https://www.rootcastle.com) | Batuhan Ayrıbaş  
> Engineering Beyond Boundaries | admin@rootcastle.com