Set up Clerk
Use the Clerk CLI to add authentication. In agent environments, supported frameworks default to accountless setup: npx -y clerk@latest init provisions a claimable application and writes temporary development keys without requiring a Clerk account.
Before you start
Show the user this checklist and wait for a yes:
Here's what I'll do to get you set up with Clerk.
1. Set up Clerk in this project, or scaffold a new app if this directory is empty.
2. Install Clerk's agent skills for the coding agents on this machine, if they aren't installed yet.
3. Start your app with Clerk installed.
Shall I proceed?
Existing authentication
Before init, inspect auth dependencies, routes, middleware, sessions, and user records — never environment files. If a different auth provider exists, stop and get approval for a migration plan covering:
- Backend API user import, stable external IDs, compatible password hashes, and OAuth continuity.
- Protected routes, tokens, session cutover, and rollout strategy.
Do not modify or remove existing auth without approval.
See the migration guide.
Existing Clerk projects
For a native iOS or macOS app, follow the iOS setup prompt instead. It reuses the linked application and keeps existing configuration.
If the project already uses Clerk, skip init in Steps 1a and 1b: a signed-out agent run could create another application and replace the project's Clerk keys. If Clerk already works and the user asked for setup, report that no setup is needed. If the user reports missing keys, restore them through the existing-application branch below. If inspection finds missing provider, middleware, or auth routes, add only those pieces from the matching quickstart in Step 2. Never create a replacement application.
Inspect its Clerk package versions before changing anything and use the version table in the clerk skill to identify its SDK generation. Preserve that generation unless the user asks to upgrade it, and apply these differences in every step below for Core 2 projects:
- React and Expo use
@clerk/clerk-reactand@clerk/clerk-expoinstead of@clerk/reactand@clerk/expo. - Control components are
<SignedIn>and<SignedOut>instead of<Show>. - Next.js
ClerkProvidercan wrap<html>instead of going inside<body>. - The minimum Node.js version is 18.17.0 instead of 20.9.0.
- Themes come from
@clerk/themesand@clerk/themes/shadcn.cssinstead of@clerk/ui.
Use an existing Clerk application (optional)
Follow this branch when the user asks to use an existing Clerk application or an existing Clerk project needs its keys restored. Have them authenticate from their host terminal before targeting account-level resources:
npx -y clerk@latest auth login
If they supplied an application ID, keep it for init or link as appropriate. Otherwise, list the applications:
npx -y clerk@latest apps list --json
Show the names and IDs and ask which application to use. Never choose an application for them. For a new Clerk integration, pass the selected ID as --app <application_id> to init. For a project already using Clerk, do not run init. If it is not already linked to the selected application, link it:
npx -y clerk@latest link --app <application_id>
For missing development keys, pull them:
npx -y clerk@latest env pull
Only when the user needs production keys, run npx -y clerk@latest deploy status --mode agent and follow its nextAction. Once production is complete, copy the keys to the host as described under "After setup". Never pull production keys without --print: a plain env pull writes them over the local development keys. Do not replace working keys or switch applications without the user's confirmation.
Step 1a: Existing project without Clerk
For a native iOS or macOS app in Xcode, follow the iOS setup prompt instead of the remaining steps.
For a project that does not already use Clerk, run from the project root:
npx -y clerk@latest init
init detects the framework and package manager, installs the SDK, and configures the provider, middleware, auth routes, and environment. It also installs Clerk's agent skills globally. If the user declined them, or they're already available to you, such as when you loaded this as the clerk-setup skill, add --no-skills to skip that step. Don't pass --framework or --pm unless asked. Add --app <application_id> only when the user selected an application in the optional branch above.
Step 1b: Empty directory
For a native iOS or macOS app, follow the iOS setup prompt instead of the remaining steps. It covers creating the Xcode project.
Ask which framework and package manager to use, defaulting to Next.js and npm:
npx -y clerk@latest init --framework <framework> --pm <package-manager>
init creates the app in a new subdirectory, such as my-clerk-next-app, not in the current directory. Run the remaining steps from that subdirectory. As in Step 1a, add --no-skills if Clerk's skills are already available to you or the user declined them.
init can create Next.js, React Router, Astro, Nuxt, TanStack Start, React, Vue, JavaScript/Vite, and Expo apps. For Express, Fastify, or Android, create the project with that platform's own tooling first, then follow Step 1a.
Step 1c: Accountless development keys
For a signed-out user on a framework with accountless support (Next.js, React Router, Astro, Nuxt, or TanStack Start), init provisions a claimable application and writes temporary keys to the detected environment file. Relay the filename and claim instruction printed by the CLI. The app stays unclaimed until the user runs npx -y clerk@latest auth login; don't run it unless asked. Use --accountless only to force this flow while signed in.
Frameworks without accountless support need real API keys. There, init applies what setup it can and prints the remaining steps.
Step 2: Fall back to docs when init is incomplete
If init reports the framework is unsupported or undetected, follow the quickstart instead. If it finishes but prints remaining steps, follow those, and use the matching quickstart for anything they don't cover.
For an existing Clerk project with missing integration files, use that quickstart to add only the missing pieces without running init.
init configures Next.js, React, React Router, Nuxt, TanStack Start, Astro, Vue, JavaScript/Vite, Expo, Express, and Fastify projects, and existing iOS and macOS Xcode projects (see the iOS setup prompt). For Android, it only prints setup steps, so follow the quickstart.
Use the matching direct quickstart:
- Next.js
- React
- React Router
- Nuxt
- TanStack Start
- Astro
- Vue
- JavaScript or Vite
- Expo
- Express
- Fastify
- iOS
- Android
- Chrome extension
For everything else, use Clerk's llms.txt.
Step 3: Add visible auth controls
Skip this step for backend-only projects, such as Express or Fastify APIs. For Expo, iOS, and Android, use the native components from the matching quickstart instead.
A web app needs sign-in, sign-up, and signed-in user controls, worked into the existing layout or navigation. If they already exist, adapt them instead of duplicating.
For Next.js App Router, when <Show> renders in a Server Component, it reads the request, so wrap it in <Suspense>:
import { SignInButton, SignUpButton, Show, UserButton } from '@clerk/nextjs'
import { Suspense } from 'react'
<Suspense>
<Show when="signed-out">
<SignInButton />
<SignUpButton />
</Show>
<Show when="signed-in">
<UserButton />
</Show>
</Suspense>
Astro imports from @clerk/astro/components. Nuxt auto-imports the components; explicit imports come from @clerk/nuxt/components. Other frameworks use the same names from their Clerk package, such as @clerk/vue or @clerk/react.
Step 4: Verify
npx -y clerk@latest doctor
Then start the app, confirm the auth controls render, and fix anything the CLI reports.
Bot protection can block sign-ups in browsers you automate. If you test a new accountless app in one, run npx -y clerk@latest users create --email <unique>+clerk_test@example.com --password <random-16-char-alphanumeric> --yes, then sign in. If asked for a verification code, enter 424242. Tell the user you created this test user. For an existing app, ask the user before creating users. To test sign-up, use @clerk/testing.
Step 5: If using shadcn/ui
If components.json exists in the project root, add @clerk/ui with the project's package manager. Match the lockfile: pnpm-lock.yaml → pnpm add, yarn.lock → yarn add, bun.lock or bun.lockb → bun add, package-lock.json → npm install.
Apply the theme in your provider:
import { shadcn } from '@clerk/ui/themes'
<ClerkProvider appearance={{ theme: shadcn }}>{children}</ClerkProvider>
Add to global CSS:
@import '@clerk/ui/themes/shadcn.css';
Critical rules
- Use Node.js 20.9.0 or later for current Clerk SDKs.
- Next.js 15+:
auth()is async. Alwaysawait auth(). - Next.js: when
next.configsetscacheComponents: true(thecreate-next-appdefault),next buildfails on request data read outside<Suspense>. Wrap<Show>rendered in a Server Component, and any Server Component that callsauth()orcurrentUser(), in<Suspense>, as close to the auth-dependent UI as possible. Wrap catch-all<SignIn />,<SignUp />,<UserProfile />, and<OrganizationProfile />pages in<Suspense>too, including the sign-in and sign-up pages the Clerk CLI creates. See Read auth data inside Suspense and Prebuilt components on catch-all routes. - For current Next.js SDKs,
ClerkProvidergoes inside<body>, not around<html>. - Never expose
CLERK_SECRET_KEYin client code. - For fresh setups, use the current framework package, such as
@clerk/nextjs,@clerk/react,@clerk/expo,@clerk/react-router, or@clerk/tanstack-react-start. - Do not read or print existing environment variable files; ask the user for any missing non-sensitive configuration.
After setup
Have the user sign up as their first test user. Congratulate them once the profile icon appears in the nav.
Ask how users should sign up and sign in: email, phone, username, and social providers. The app must be claimed before changing these settings.
If init created the app in this session and no SDK claim file exists, use the init claim steps below. Otherwise, if .clerk/keyless.json (init) or .clerk/.tmp/keyless.json (SDK) exists, ask which app the project should use before anyone signs in or links it.
If both claim files exist, stop before auth login, open, or link: open prefers the init claim, even if the user chose the SDK app. Have the user identify which claim belongs to the app whose keys the project uses, move the other file out of the project, and keep it private. Never read the claim files or keys. Continue only after the user confirms that the remaining file and the project's keys belong to the chosen app.
initclaim: If this is the chosen app, have the user runnpx -y clerk@latest auth login. On older CLIs, signing in from this folder claims theinitapp and replaces the project's keys; a signed-outnpx -y clerk@latest linkcan start that sign-in. If the user chose another app, have them sign in from another folder first.- SDK claim: Have the user run
npx -y clerk@latest openin their own terminal to open the claim page, thennpx -y clerk@latest link. Signing in cannot claim an SDK-created app.
Once the app is claimed, review settings with npx -y clerk@latest config pull and change them with npx -y clerk@latest config patch (supports --dry-run), or use the Clerk Dashboard. See sign-up and sign-in options.
When the user is ready for production:
- Have them claim the app as described above, because unclaimed apps and temporary keys aren't production-ready. If
deploysays the project isn't linked, follow its instructions. - Ask which domain they own for production, one whose DNS they can change (not a hosting provider's URL such as
*.vercel.app), and runnpx -y clerk@latest deploy --mode agent --domain <domain>. It creates the production instance and prints a JSON report. - Follow the report's
nextActionat each step. If a command from the report ornextActioncalls plain clerk, as all of them do on Windows (inside thehostSetupcommand too), and clerk isn't installed, replace that call withnpx -y clerk@latestand keep the rest of the command, including in commands the user runs.nextAction's OAuth steps need bash or zsh. In any other shell, have the user enter the OAuth credentials by runningnpx -y clerk@latest deployin their own terminal, from the project directory. Pass on eachoauth.setupentry'snoteto the user, such as Google's reminder to set the OAuth consent screen to "In production". - Check progress with
npx -y clerk@latest deploy status --mode agent, which exits 0 only when production is complete. - On Vercel, if
vercelisn't installed or you can't run bash or zsh, follow step 6. Otherwise, runvercel whoamiyourself, which doesn't start a login just because you're logged out. If it prints "Logged out.", have the user runvercel loginin their own terminal. Then, if the user confirms this directory is linked to the Vercel project that serves this app in production, copy the production keys by running thecommandof the report'shostSetupentry as given. If either command doesn't exit, Vercel is waiting for a browser login: stop it, have the user run the command that hung in their own terminal, from the project directory, and finish the login it opens, then rerun. - On any other host, or if the user doesn't confirm the Vercel project, have the user run the
env pull --printcommand fromnextActionin a separate terminal in the project directory, not through your session, and add the printed lines to the host. Never write your own pipe into a host's CLI. - Have the user add the other Clerk variables from their env file to the host too.
Then offer Organizations — multi-tenancy, team invitations, roles and permissions, and enterprise SSO.
If yes:
- Run
npx -y clerk@latest enable orgs. - Add
<OrganizationSwitcher />next to the existing<UserButton />, or the framework equivalent. - Have them create an organization from the switcher and invite a teammate.
If no, point them to Organizations, Components, and the Clerk Dashboard.