Add Clerk Authentication

Set up Clerk authentication with the Clerk CLI. Interactive by default: present the checklist, pause while the user completes the browser-side login flow, and continue from CLI output. Before driving the CLI from a script or sandbox, read references/agent-mode.md.

Reference files — load on demand when their trigger hits, not upfront: windows-cli.md (Windows install/npm failure, PowerShell quoting) · agent-mode.md (headless/scripted CLI) · local-conventions.md (app-ID and key resolution/persistence) · split-stack.md (Vite SPA + non-Node backend) · operations.md (sign-up gatekeeping, invitations, org trap).

Ecosystem: compose, don't duplicate

Clerk ships a first-class AI-native stack (skills, CLI agent mode, MCP server, prompts). This pack is a Windows-capable, convention-carrying wrapper over that stack — not a replacement.

• Framework setup depth, framework patterns, orgs, billing, webhooks, testing, mobile -> official skills: npx skills add clerk/skills (https://github.com/clerk/skills); clerk init also offers to install them
• Up-to-date SDK snippets inside AI clients -> clerk mcp install (also clerk mcp list, clerk mcp uninstall)
• Non-interactive CLI automation -> references/agent-mode.md; official reference: https://github.com/clerk/skills/blob/main/skills/core/clerk-cli/references/agent-mode.md
• Cross-project app-ID resolution, credential storage, Windows CLI reality, non-Next.js key routing -> this pack

Ecosystem overview: https://clerk.com/docs/guides/ai/overview

Preliminary setup checklist

Before running any commands, present the user with this checklist:

Here's what I'll do to get you set up with Clerk.

1. Install or update the Clerk CLI
2. Set up Clerk in this project, or scaffold a new app if it's empty
3. Verify the Next.js proxy matcher when applicable
4. Start your app with Clerk installed.

Shall I proceed?

Step 1: Install or update the Clerk CLI

Probe first: command -v clerk && clerk --version.

• Already installed -> update with clerk update --yes.
• Missing -> try the standard install: npm install -g clerk (equivalents: pnpm / yarn / bun / brew install clerk/stable/clerk, or curl -fsSL https://clerk.com/install | bash). Without installing: npx clerk@latest <command> / bunx clerk.
• On Windows, if the install or npx clerk fails with "Unsupported or missing platform: win32-x64" or an npm 404 for a platform package, read references/windows-cli.md before pinning anything — it carries the verified workarounds and a recheck procedure.

Step 2: Sign in to Clerk

Immediately after installing or updating the CLI, from the project root run clerk auth login. This is the first command after install or update — do not list apps, ask which Clerk app to use, or run clerk init before authenticating. It opens a browser and binds a localhost callback; pause while the user completes the flow, then continue from CLI output. If already signed in, continue to initialization. Verify with clerk whoami.

Sandbox/headless: clerk auth login has no headless branch — it stalls. Use CLERK_PLATFORM_API_KEY for headless automation, or hand the login step back to the user and wait. Full agent-mode rules: references/agent-mode.md.

Step 3: Initialize Clerk

Resolve the app ID first — never invent one or reuse another project's. Short version: check ~/.agents/env/clerk.env (project-name = app_id lines), then a pasted personalized SKILL.md, then clerk apps list --json

• ask the user to pick. Full resolution order and persistence rules: references/local-conventions.md.

Inspect the current directory to determine whether this is an existing project or an empty directory.

Existing project: clerk init --app <app-id>. It detects the framework and package manager, installs the correct SDK, and applies framework-specific setup (providers, middleware, auth routes, env config). Do not pass --framework or --pm for existing projects unless the user explicitly wants to override detection or the CLI asks for those values.

Empty directory: ask which framework and package manager the user wants; no preference -> Next.js and npm. Scaffold explicitly: clerk init --framework <framework> --pm <package-manager> --app <app-id>. Non-interactive: clerk init -y skips confirmation prompts.

Package-manager signals on a non-empty directory: pnpm-lock.yaml -> pnpm; yarn.lock -> yarn; bun.lock/bun.lockb -> bun; package-lock.json -> npm; none detected -> npm.

Keyless bootstrap: an unauthenticated agent on keyless-capable frameworks defaults to keyless — clerk init mints an unclaimed app with temporary development keys; a later clerk auth login claims it automatically. --keyless forces keyless over a stale link; --login forces the authenticated flow.

Step 4: Verify the Next.js matcher

After clerk init, if the project uses Next.js, check proxy.ts (or middleware.ts on Next.js 15 and earlier). config.matcher must include Clerk's auto-proxy path once, after the API/TRPC matcher:

'/(api|trpc)(.*)',
'/__clerk/:path*',

Add '/__clerk/:path*' if it is missing.

Step 5: Fall back to docs when init is incomplete

If clerk init reports the framework as unsupported, undetectable, or only partially supported, follow the official quickstart (it fully scaffolds Next.js App/Pages Router, React, React Router, Nuxt, TanStack Start, Astro, Vue, JS/Vite; Expo, Express, Fastify get the SDK plus docs steps). Quickstart URL pattern: https://clerk.com/docs/<slug>/getting-started/quickstart with slug: nextjs, react-router (Remix), astro, nuxt, tanstack-react-start, react, vue, js-frontend (Vite/vanilla JS), expressjs, fastify, expo (iOS/Android/Chrome Extension have their own doc sections). Everything else: https://clerk.com/docs/llms.txt

Step 6: Ensure clear auth controls are visible

Make sure the app has clear sign-in, sign-up, and signed-in user controls so the user can create and recognize their first account. Integrate them into the existing layout; if clear auth controls already exist, reuse or adapt them instead of duplicating them.

For Next.js App Router, use Clerk components from @clerk/nextjs:

import { SignInButton, SignUpButton, Show, UserButton } from '@clerk/nextjs'

<Show when="signed-out"><SignInButton /><SignUpButton /></Show>
<Show when="signed-in"><UserButton /></Show>

Other frameworks use the same component names from their own Clerk package (@clerk/vue, @clerk/nuxt, ...). Vite SPA: React SDK wrapped in ClerkProvider, publishable key from VITE_CLERK_PUBLISHABLE_KEY (public by design); a separate backend receives only the sk_ key in its own env. For the full SPA + non-Node backend wiring pattern, read references/split-stack.md.

Step 7: Verify the setup

After clerk init completes, run clerk doctor. In agent mode, doctor --fix is ignored — read each check's remedy field (clerk doctor --json) and apply fixes yourself. Then start the app, confirm the auth controls are visible, and test the sign-in and sign-up flow.

Step 8: If using shadcn/ui

If components.json exists in the project root and Clerk components are used: npm install @clerk/ui, apply the theme in your provider (import { shadcn } from '@clerk/ui/themes', then <ClerkProvider appearance={{ theme: shadcn }}>, and add @import '@clerk/ui/themes/shadcn.css'; to global CSS.

Safety rules

• Next.js 15+: auth() is async. Always await auth().
• ClerkProvider goes inside <body>, not wrapping <html>.
• Use @clerk/nextjs in Next.js; @clerk/clerk-react is for React SPAs.
• Secret keys (sk_) never enter client code, frontend env, or git.
• Gate integrations on key presence so key absence = exact legacy behavior.
• Server-side sk_ calls hit api.clerk.com, never the Frontend API host (details in references/split-stack.md — this cost us a real bug once).
• Do not trawl env/secrets files hunting for Clerk values on your own initiative; read only files the user pointed you at, and ask for anything missing (references/local-conventions.md).

After setup

Run the app and have the user create their first account through the UI. If sign-up needs restricting, invitations are wanted, or the dashboard enabled orgs by accident, read references/operations.md. For deeper framework patterns (orgs, billing, webhooks, testing, mobile), install the official skills: npx skills add clerk/skills.

Docs: https://clerk.com/docs/cli https://clerk.com/docs/llms.txt Dashboard: https://dashboard.clerk.com/