kausthubh-coder/clerk-setup

Adding Clerk

This skill sets up Clerk for authentication by following the official quickstart documentation.

Quick Reference

| Step | Action | |------|--------| | 1. Detect framework | Check package.json dependencies | | 2. Fetch quickstart | Use WebFetch on the appropriate docs URL | | 3. Follow instructions | Execute the steps from the official guide | | 4. Get API keys | From dashboard.clerk.com |

Framework Detection

Check package.json to identify the framework:

| Dependency | Framework | Quickstart URL | |------------|-----------|----------------| | next | Next.js | https://clerk.com/docs/nextjs/getting-started/quickstart | | @remix-run/react | Remix | https://clerk.com/docs/remix/getting-started/quickstart | | astro | Astro | https://clerk.com/docs/astro/getting-started/quickstart | | nuxt | Nuxt | https://clerk.com/docs/nuxt/getting-started/quickstart | | react-router | React Router | https://clerk.com/docs/react-router/getting-started/quickstart | | @tanstack/react-start | TanStack Start | https://clerk.com/docs/tanstack-react-start/getting-started/quickstart | | react (no framework) | React SPA | https://clerk.com/docs/react/getting-started/quickstart | | vue | Vue | https://clerk.com/docs/vue/getting-started/quickstart | | express | Express | https://clerk.com/docs/expressjs/getting-started/quickstart | | fastify | Fastify | https://clerk.com/docs/fastify/getting-started/quickstart | | expo | Expo | https://clerk.com/docs/expo/getting-started/quickstart |

For other platforms:

• Chrome Extension: https://clerk.com/docs/chrome-extension/getting-started/quickstart
• Android: https://clerk.com/docs/android/getting-started/quickstart
• iOS: https://clerk.com/docs/ios/getting-started/quickstart
• Vanilla JavaScript: https://clerk.com/docs/js-frontend/getting-started/quickstart

Decision Tree

User Request: "Add Clerk" / "Add authentication"
    │
    ├─ Read package.json
    │
    ├─ Existing auth detected?
    │   │
    │   ├─ YES → Audit current auth → Create migration plan
    │   │        → See "Migrating from Another Auth Provider"
    │   │
    │   └─ NO → Fresh install
    │
    ├─ Identify framework from dependencies
    │
    ├─ WebFetch the appropriate quickstart URL
    │
    └─ Follow the official instructions step-by-step

Setup Process

1. Detect the Framework

Read the project's package.json and match dependencies to the table above.

2. Fetch the Quickstart Guide

Use WebFetch to retrieve the official quickstart for the detected framework:

WebFetch: https://clerk.com/docs/{framework}/getting-started/quickstart
Prompt: "Extract the complete setup instructions including all code snippets, file paths, and configuration steps."

3. Follow the Instructions

Execute each step from the quickstart guide:

• Install the required packages
• Set up environment variables
• Add the provider/middleware
• Create sign-in/sign-up routes if needed
• Test the integration

4. Get API Keys

Two paths for development API keys:

Keyless (Automatic)

• On first SDK initialization, Clerk auto-generates dev keys and shows "Claim your application" popover
• No manual key setup required—keys are created and injected automatically
• Simplest path for new projects

Manual (Dashboard)

• Get keys from dashboard.clerk.com if Keyless doesn't trigger
• Publishable Key: Starts with pk_test_ or pk_live_
• Secret Key: Starts with sk_test_ or sk_live_
• Set as environment variables: NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY and CLERK_SECRET_KEY

Migrating from Another Auth Provider

If the project already has authentication, create a migration plan before replacing it.

Detect Existing Auth

Check package.json for existing auth libraries:

• next-auth / @auth/core → NextAuth/Auth.js
• @supabase/supabase-js → Supabase Auth
• firebase / firebase-admin → Firebase Auth
• @aws-amplify/auth → AWS Cognito
• auth0 / @auth0/nextjs-auth0 → Auth0
• passport → Passport.js
• Custom JWT/session implementation

Migration Process

1. Audit current auth - Identify all auth touchpoints:

   • Sign-in/sign-up pages
   • Session/token handling
   • Protected routes and middleware
   • User data storage (database tables, external IDs)
   • OAuth providers configured

2. Create migration plan - Consider:

   • User data export - Export users and import via Clerk's Backend API
   • Password hashes - Clerk can upgrade hashes to Bcrypt transparently
   • External IDs - Store legacy user IDs as external_id in Clerk
   • Session handling - Existing sessions will terminate on switch

3. Choose migration strategy:

   • Big bang - Switch all users at once (simpler, requires maintenance window)
   • Trickle migration - Run both systems temporarily (lower risk, higher complexity)

Migration Reference

• Migration Overview: https://clerk.com/docs/guides/development/migrating/overview

Common Pitfalls

| Level | Issue | Solution | |-------|-------|----------| | CRITICAL | Missing await on auth() | In Next.js 15+, auth() is async: const { userId } = await auth() | | CRITICAL | Exposing CLERK_SECRET_KEY | Never use secret key in client code; only NEXT_PUBLIC_* keys are safe | | HIGH | Missing middleware matcher | Include API routes: matcher: ['/((?!.*\\..*|_next).*)', '/'] | | HIGH | ClerkProvider not at root | Must wrap entire app in root layout/App component | | HIGH | Auth routes not public | Allow /sign-in, /sign-up in middleware config | | HIGH | Landing page requires auth | To keep "/" public, exclude it: matcher: ['/((?!.*\\..*|_next|^/$).*)', '/api/(.*)'] | | MEDIUM | Wrong import path | Server code uses @clerk/nextjs/server, client uses @clerk/nextjs |

See Also

• custom-flows/ - Custom sign-in/up components
• syncing-users/ - Webhook → database sync
• managing-orgs/ - B2B multi-tenant organizations
• testing/ - E2E testing setup
• nextjs-patterns/ - Advanced Next.js patterns

Documentation

• Quickstart Overview: https://clerk.com/docs/getting-started/quickstart/overview
• Migration Guide: https://clerk.com/docs/guides/development/migrating/overview
• Full Documentation: https://clerk.com/docs