clerk-authentication

clerk-authentication is a skill for Claude Code, Codex from Mindrally/skills. It costs 24 tokens per session (2,908 once invoked), scanned A, original, Apache-2.0.

Guidance for adding Clerk, a hosted user sign-in service, to Next.js applications. It covers provider setup, environment variables, middleware, hooks, server actions, and checks around protected data access.

In plain words
What is it for?
Use it when adding sign-up and sign-in, protecting Next.js routes and server actions, configuring Clerk keys, or sending users to custom authentication pages.
Why use it?
It helps prevent relying on a single login check in the wrong place. The guidance keeps authentication checks close to the data and actions they protect.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when adding sign-up and sign-in, protecting Next.js routes and server actions, configuring Clerk keys, or sending users to custom authentication pages.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mindrally/skills/clerk-authentication
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add Mindrally/skills --skill clerk-authentication
Clone the repo
git clone --depth 1 https://github.com/Mindrally/skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for clerk-authentication

README.md
[![agentmods](https://agentmods.dev/badge/skills/mindrally/skills/clerk-authentication.svg)](https://agentmods.dev/skills/mindrally/skills/clerk-authentication)
Your own site
<a href="https://agentmods.dev/skills/mindrally/skills/clerk-authentication"><img src="https://agentmods.dev/badge/skills/mindrally/skills/clerk-authentication.svg" alt="Measured on agentmods" height="20"></a>
Per session 24 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,908 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Socket pass 18 Mar 2026
  • Snyk pass 15 Feb 2026
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00024 $0.02908
Opus 5 $0.00012 $0.01454
Sonnet 5 $0.00005 $0.00582
Haiku 4.5 $0.00002 $0.00291

Measured 8d ago against content hash 05f5b11ac782, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

clerk-authentication scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

clerk-authentication/SKILL.md · 562 lines

How it starts

The opening of the file, as written. The whole thing — 562 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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

npm install @clerk/nextjs

Environment Variables

# 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)

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

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)

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)(.*)',
  ],
};

Read the full file on GitHub · 562 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 562 lines · 24 tokens per session scan A 05f5b11ac782

Subscribe to this mod's changes

clerk-authentication is a skill published in the GitHub repository Mindrally/skills (258 stars, last pushed 4d ago), licensed Apache-2.0. It adds 24 tokens to every session and 2,908 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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