Clerk Setup

Adding Clerk

Version: Check package.json for the SDK version — see clerk skill for the version table. Core 2 differences are noted inline with > **Core 2 ONLY (skip if current SDK):** callouts.

This skill sets up Clerk for authentication by following the official quickstart documentation. For agents, the clerk CLI handles most of this end to end — see the next section.

Agent-first: Provision via CLI

The clerk CLI replaces most Dashboard clicks. Three scenarios cover almost everything:

Scenario A — New project, new Clerk app

clerk init --framework <next|react|vue|nuxt|astro|react-router|tanstack-react-start|expressjs|fastify|expo> -y

clerk init creates the Clerk app via PLAPI, links the project, writes the framework-specific publishable + secret keys to the right env file (e.g. .env.local for Next.js, .env for Vite-based projects), and installs the SDK package.

Scenario B — Existing project, existing Clerk app

clerk auth login                      # one-time OAuth (skip if already logged in)
clerk link                            # autolinks if a CLERK_PUBLISHABLE_KEY is in your .env
clerk link --app app_xxx              # explicit form, required in agent mode
clerk env pull                        # writes the framework-detected env vars

Scenario C — Existing project, new Clerk app

clerk auth login
clerk apps create "My App" --json     # returns the new app_id
clerk link --app app_xxx
clerk env pull

Daily ops

clerk env pull                        # refresh keys (uses linked profile)
clerk env pull --instance prod        # production keys
clerk doctor --json                   # framework integration health check

Rotate the secret key (replaces Dashboard rotation)

PLAPI exposes secret-key rotation directly. Use raw clerk api until the friendly wrapper ships:

clerk api --platform POST /v1/platform/applications/<app_id>/rotate_secret_keys \
  -d '{"delay_old_secrets_expiration_hours": 24, "reason": "scheduled rotation"}'

delay_old_secrets_expiration_hours keeps the old key valid for the grace period so deploys can roll forward without downtime.

Notes for agents

• clerk link (no flags) only autolinks when a CLERK_PUBLISHABLE_KEY is already in .env / .env.local. Without it, agent mode errors out: "Cannot select an application in agent mode." When that happens, run clerk apps list --json, and ask the user which app_id to link rather than guessing.
• Pass --json on apps list/create, users create, and doctor for parseable output.
• The CLI auto-detects framework env var names (VITE_CLERK_PUBLISHABLE_KEY for Vite, NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY for Next.js, etc.) and target file (.env.development.local > .env.local > .env).

Quick Reference (Dashboard fallback)

If the CLI isn't an option (sandboxed environments, docs walkthroughs), here's the manual Dashboard path:

If the project has components.json (shadcn/ui), apply the shadcn theme after setup. See clerk-custom-ui skill → shadcn Theme.

Framework Detection

Check package.json to identify the framework:

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 → Migration plan
    │   └─ NO → Fresh install
    │
    ├─ Identify framework → WebFetch quickstart → Follow instructions
    │   └─ Next.js? → Create proxy.ts (Next.js <=15: middleware.ts)
    │
    └─ components.json exists? → YES → Apply shadcn theme (see clerk-custom-ui)

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 and proxy/middleware
• Create sign-in/sign-up routes if needed
• Test the integration

Next.js: Create proxy.ts (Next.js <=15: middleware.ts). See the clerk-nextjs-patterns skill for middleware strategies.

shadcn/ui detected (components.json exists): ALWAYS apply the shadcn theme. See clerk-custom-ui skill → shadcn Theme section.

4. Get API Keys

Two paths for development API keys:

Keyless (Automatic)

• On first SDK initialization, Clerk auto-generates dev keys and shows a "Configure your application" button in the bottom right of the running app
• No manual key setup required, keys are created and injected automatically
• Selecting "Configure your application" associates the auto-generated app with your Clerk account so you can edit it from the Dashboard
• 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