What does the Clerk Authentication AI skill do?

Guidelines for implementing Clerk authentication in Next.js applications with middleware, hooks, and security best practices

Why use Clerk Authentication on TypingMind?

Because you install it once and use it with any model. Clerk Authentication is plain Markdown rather than provider-specific code, so the same skill runs on GPT-5, Claude, Gemini, Grok, or a local model — and you can switch model mid-chat without it breaking. TypingMind runs on your own API keys, so you pay providers directly instead of a per-seat subscription, and your skills and chats stay in your own storage.

How do I install Clerk Authentication in TypingMind?

Open Plugins → Skills → Install from GitHub in TypingMind and paste https://github.com/Mindrally/skills/tree/main/clerk-authentication. TypingMind reads its SKILL.md and installs it as a skill you can enable per chat.

Which AI models can use Clerk Authentication?

Any model you connect in TypingMind. AI skills are plain Markdown instructions rather than provider-specific code, so GPT, Claude, Gemini, Grok, and local models can all load this skill when a request matches it.

How many AI models can I use with Clerk Authentication?

As many as you like. As long as a model supports skills, you can use Clerk Authentication with it — GPT, Claude, Gemini, Grok, DeepSeek, Mistral, Llama and more — all on TypingMind with your own API keys.

Is the Clerk Authentication AI skill free?

Yes. It is published on GitHub by Mindrally under the Apache-2.0 license. You only pay your own AI provider for the tokens you use.

An AI skill is a reusable instruction bundle that teaches an AI model how to do one specific task. It follows the open Agent Skills format: a SKILL.md file with a name and description, plus any scripts, templates or reference files the model may need. The model reads the instructions only when your request matches the skill, so an installed skill costs nothing until it is used.

How are AI skills different from plugins or MCP servers?

A plugin or MCP server gives a model new tools to call — code that runs somewhere and returns a result. An AI skill gives the model knowledge and process instead: how to approach a task, which steps to follow, what good output looks like. Skills are plain Markdown, so they need no server, no API key and no runtime, and they work with any model.

Clerk Authentication by Mindrally — AI Skill for Any LLM

Clerk Authentication

You are an expert in Clerk authentication implementation for Next.js applications. Follow these guidelines when integrating Clerk.

Core Principles

Implement defense-in-depth with multiple authentication layers
Verify authentication at every data access point, not just middleware
Protect server actions individually
Use Clerk's built-in security features (HttpOnly cookies, CSRF protection)

Installation and Setup

bash
npm install @clerk/nextjs

Environment Variables

bash
# Required
NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY=pk_...
CLERK_SECRET_KEY=sk_...

# Optional: Custom URLs
NEXT_PUBLIC_CLERK_SIGN_IN_URL=/sign-in
NEXT_PUBLIC_CLERK_SIGN_UP_URL=/sign-up
NEXT_PUBLIC_CLERK_AFTER_SIGN_IN_URL=/dashboard
NEXT_PUBLIC_CLERK_AFTER_SIGN_UP_URL=/dashboard

Provider Setup

App Router (app/layout.tsx)

typescript
import { ClerkProvider } from '@clerk/nextjs';

export default function RootLayout({
  children,
}: {
  children: React.ReactNode;
}) {
  return (
    <ClerkProvider>
      <html lang="en">
        <body>{children}</body>
      </html>
    </ClerkProvider>
  );
}

With Custom Appearance

typescript
import { ClerkProvider } from '@clerk/nextjs';
import { dark } from '@clerk/themes';

export default function RootLayout({ children }: { children: React.ReactNode }) {
  return (
    <ClerkProvider
      appearance={{
        baseTheme: dark,
        variables: {
          colorPrimary: '#3b82f6',
        },
        elements: {
          formButtonPrimary: 'bg-blue-500 hover:bg-blue-600',
        },
      }}
    >
      <html lang="en">
        <body>{children}</body>
      </html>
    </ClerkProvider>
  );
}

Middleware Configuration

Basic Middleware (middleware.ts)

typescript
import { clerkMiddleware, createRouteMatcher } from '@clerk/nextjs/server';

// Define protected routes
const isProtectedRoute = createRouteMatcher([
  '/dashboard(.*)',
  '/api/protected(.*)',
  '/settings(.*)',
]);

// Define public routes (optional, for clarity)
const isPublicRoute = createRouteMatcher([
  '/',
  '/sign-in(.*)',
  '/sign-up(.*)',
  '/api/public(.*)',
]);

export default clerkMiddleware(async (auth, req) => {
  if (isProtectedRoute(req)) {
    await auth.protect();
  }
});

export const config = {
  matcher: [
    // Skip Next.js internals and static files
    '/((?!_next|[^?]*\\.(?:html?|css|js(?!on)|jpe?g|webp|png|gif|svg|ttf|woff2?|ico|csv|docx?|xlsx?|zip|webmanifest)).*)',
    // Always run for API routes
    '/(api|trpc)(.*)',
  ],
};

Advanced Middleware with Role-Based Access

typescript
import { clerkMiddleware, createRouteMatcher } from '@clerk/nextjs/server';

const isAdminRoute = createRouteMatcher(['/admin(.*)']);
const isProtectedRoute = createRouteMatcher(['/dashboard(.*)', '/api/protected(.*)']);

export default clerkMiddleware(async (auth, req) => {
  const { userId, sessionClaims } = await auth();

  // Admin routes require admin role
  if (isAdminRoute(req)) {
    if (!userId || sessionClaims?.metadata?.role !== 'admin') {
      return new Response('Forbidden', { status: 403 });
    }
  }

  // Protected routes require authentication
  if (isProtectedRoute(req)) {
    await auth.protect();
  }
});

Authentication in Server Components

Using auth()

typescript
import { auth } from '@clerk/nextjs/server';

export default async function DashboardPage() {
  const { userId } = await auth();

  if (!userId) {
    redirect('/sign-in');
  }

  // Fetch user-specific data
  const data = await fetchUserData(userId);

  return <Dashboard data={data} />;
}

Using currentUser()

typescript
import { currentUser } from '@clerk/nextjs/server';

export default async function ProfilePage() {
  const user = await currentUser();

  if (!user) {
    redirect('/sign-in');
  }

  return (
    <div>
      <h1>Welcome, {user.firstName}!</h1>
      <p>Email: {user.emailAddresses[0]?.emailAddress}</p>
    </div>
  );
}

Authentication in Client Components

useUser Hook

typescript
'use client';

import { useUser } from '@clerk/nextjs';

export function UserProfile() {
  const { isLoaded, isSignedIn, user } = useUser();

  if (!isLoaded) {
    return <Skeleton />;
  }

  if (!isSignedIn) {
    return <SignInPrompt />;
  }

  return (
    <div>
      <img src={user.imageUrl} alt={user.fullName ?? 'User'} />
      <p>{user.fullName}</p>
    </div>
  );
}

useAuth Hook

typescript
'use client';

import { useAuth } from '@clerk/nextjs';

export function ProtectedAction() {
  const { isLoaded, userId, getToken } = useAuth();

  async function handleAction() {
    if (!userId) return;

    // Get a fresh token for API calls
    const token = await getToken();

    const response = await fetch('/api/protected', {
      headers: {
        Authorization: `Bearer ${token}`,
      },
    });
  }

  if (!isLoaded || !userId) {
    return null;
  }

  return <button onClick={handleAction}>Perform Action</button>;
}

Server Actions Protection

Always protect server actions individually:

typescript
'use server';

import { auth } from '@clerk/nextjs/server';

export async function createPost(formData: FormData) {
  const { userId } = await auth();

  if (!userId) {
    throw new Error('Unauthorized');
  }

  const title = formData.get('title') as string;
  const content = formData.get('content') as string;

  // Create post with user ID
  const post = await db.post.create({
    data: {
      title,
      content,
      authorId: userId,
    },
  });

  revalidatePath('/posts');
  return post;
}

With Role Validation

typescript
'use server';

import { auth } from '@clerk/nextjs/server';

export async function deleteUser(userId: string) {
  const { userId: currentUserId, sessionClaims } = await auth();

  if (!currentUserId) {
    throw new Error('Unauthorized');
  }

  if (sessionClaims?.metadata?.role !== 'admin') {
    throw new Error('Forbidden: Admin access required');
  }

  await db.user.delete({ where: { id: userId } });
  revalidatePath('/admin/users');
}

API Route Protection

Route Handlers (App Router)

typescript
import { auth } from '@clerk/nextjs/server';
import { NextResponse } from 'next/server';

export async function GET() {
  const { userId } = await auth();

  if (!userId) {
    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
  }

  const data = await fetchUserData(userId);
  return NextResponse.json(data);
}

export async function POST(request: Request) {
  const { userId } = await auth();

  if (!userId) {
    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
  }

  const body = await request.json();
  // Process request...

  return NextResponse.json({ success: true });
}

JWT Verification for External APIs

typescript
import { auth } from '@clerk/nextjs/server';

export async function GET() {
  const { getToken } = await auth();

  // Get JWT for external API
  const token = await getToken({ template: 'external-api' });

  const response = await fetch('https://external-api.com/data', {
    headers: {
      Authorization: `Bearer ${token}`,
    },
  });

  return Response.json(await response.json());
}

Organization Support

typescript
import { auth } from '@clerk/nextjs/server';

export async function getOrganizationData() {
  const { userId, orgId, orgRole } = await auth();

  if (!userId || !orgId) {
    throw new Error('Must be in an organization');
  }

  // Check organization role
  if (orgRole !== 'org:admin') {
    throw new Error('Admin access required');
  }

  return await db.organization.findUnique({
    where: { clerkOrgId: orgId },
  });
}

Custom Session Claims

Configure in Clerk Dashboard

Add custom claims via JWT Templates, then access them:

typescript
import { auth } from '@clerk/nextjs/server';

export async function checkSubscription() {
  const { sessionClaims } = await auth();

  const plan = sessionClaims?.metadata?.subscriptionPlan;

  if (plan !== 'pro') {
    throw new Error('Pro subscription required');
  }
}

UI Components

Pre-built Components

typescript
import {
  SignIn,
  SignUp,
  SignOutButton,
  UserButton,
  SignedIn,
  SignedOut,
} from '@clerk/nextjs';

export function Header() {
  return (
    <header>
      <SignedIn>
        <UserButton afterSignOutUrl="/" />
      </SignedIn>
      <SignedOut>
        <SignInButton mode="modal" />
      </SignedOut>
    </header>
  );
}

// Dedicated sign-in page
export default function SignInPage() {
  return (
    <div className="flex justify-center items-center min-h-screen">
      <SignIn />
    </div>
  );
}

Security Best Practices

1. Defense in Depth

typescript
// Layer 1: Middleware
export default clerkMiddleware(async (auth, req) => {
  if (isProtectedRoute(req)) {
    await auth.protect();
  }
});

// Layer 2: Server Component
export default async function Page() {
  const { userId } = await auth();
  if (!userId) redirect('/sign-in');
  // ...
}

// Layer 3: Data Access
async function fetchUserData(userId: string) {
  const { userId: currentUserId } = await auth();
  if (currentUserId !== userId) throw new Error('Forbidden');
  // ...
}

2. Protect All Server Actions

typescript
// Every server action should verify auth independently
'use server';

export async function sensitiveAction() {
  const { userId } = await auth();
  if (!userId) throw new Error('Unauthorized');
  // ...
}

3. Avoid Client-Side Only Protection

typescript
// BAD: Client-side only check
'use client';
export function SecretComponent() {
  const { isSignedIn } = useAuth();
  if (!isSignedIn) return null;
  return <div>Secret Data</div>; // Data still sent to client!
}

// GOOD: Server-side protection
export default async function SecretPage() {
  const { userId } = await auth();
  if (!userId) redirect('/sign-in');
  const data = await fetchSecretData(userId);
  return <SecretComponent data={data} />;
}

Error Handling

typescript
import { auth } from '@clerk/nextjs/server';
import { redirect } from 'next/navigation';

export default async function ProtectedPage() {
  try {
    const { userId } = await auth();

    if (!userId) {
      redirect('/sign-in');
    }

    const data = await fetchUserData(userId);
    return <Dashboard data={data} />;
  } catch (error) {
    if (error instanceof AuthenticationError) {
      redirect('/sign-in');
    }
    throw error;
  }
}

Testing

typescript
// Mock Clerk for testing
import { auth } from '@clerk/nextjs/server';

jest.mock('@clerk/nextjs/server', () => ({
  auth: jest.fn(),
}));

describe('Protected API', () => {
  it('returns 401 for unauthenticated requests', async () => {
    (auth as jest.Mock).mockResolvedValue({ userId: null });

    const response = await GET();
    expect(response.status).toBe(401);
  });

  it('returns data for authenticated requests', async () => {
    (auth as jest.Mock).mockResolvedValue({ userId: 'user_123' });

    const response = await GET();
    expect(response.status).toBe(200);
  });
});

Common Anti-Patterns to Avoid

Relying solely on middleware for protection
Not protecting server actions individually
Using client-side auth checks for sensitive data
Exposing user data without ownership verification
Not validating organization membership for org-scoped resources
Hardcoding role checks instead of using Clerk's RBAC
Not handling loading states in client components

Publisher	Mindrally
Repository	`skills`
Skill name	`clerk-authentication`
Stars	259
Forks	41
Bundled files	Instructions only
License	Apache-2.0
Links	Skill source Repository

Overview

Installation

Install in TypingMind

Install in another agent

Use it in TypingMind

Works with any AI model

Skill instructions

Clerk Authentication

Core Principles

Installation and Setup

Environment Variables

Provider Setup

App Router (app/layout.tsx)

With Custom Appearance

Middleware Configuration

Basic Middleware (middleware.ts)

Advanced Middleware with Role-Based Access

Authentication in Server Components

Using auth()

Using currentUser()

Authentication in Client Components

useUser Hook

useAuth Hook

Server Actions Protection

With Role Validation

API Route Protection

Route Handlers (App Router)

JWT Verification for External APIs

Organization Support

Custom Session Claims

Configure in Clerk Dashboard

UI Components

Pre-built Components

Security Best Practices

1. Defense in Depth

2. Protect All Server Actions

3. Avoid Client-Side Only Protection

Error Handling

Testing

Common Anti-Patterns to Avoid

Frequently asked questions

Related AI Skills

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