Free tool · Next.js 16.3+ · Cursor · Claude Code

Paste your AGENTS.md.
See what your agent is missing.

Next.js now writes part of your AGENTS.md for you. This checks the part you have to write yourself: stack, commands and the auth and payment rules agents most often break.

agents-md-checker — runs in your browser, nothing is sent or stored

$ paste your AGENTS.md

try:

next: skip the next one

Skip the guesswork. The VibeBoot SaaS Starter ships with this already handled: an AGENTS.md, CLAUDE.md and three .cursor/rules files written for its own code, plus auth, Stripe and a database on Next.js 16.4.3. $49, one-time.

14-day money-back guarantee · lifetime updates

Get the SaaS Starter What's inside →

Building an AI chat app? The AI Chatbot Starter ships streaming chat, saved conversations, Free/Pro usage limits enforced on the server and Stripe, with AGENTS.md and .cursor/rules. Get the AI Chatbot Starter, $59

managed block · stack · commands · guardrails
nothing leaves your browser
checked Oct 27, 2026

01What it checks

Next.js writes one block. You write the rest.

Since Next.js 16.3, next dev adds a managed block between BEGIN:nextjs-agent-rules and END:nextjs-agent-rules markers when it detects a coding agent. The block points the agent at the docs bundled with your installed Next.js version. Next.js only updates what's between the markers. Your project's rules are still up to you, and this checker looks for:

→The managed block: whether it's there, whether the markers are intact, and whether the file has anything outside it.
→Stack and version: the framework version, auth, database, TypeScript, and proxy.ts on Next.js 16.
→Commands: test, lint, build and typecheck, plus a definition of done.
→Guardrails: server-side auth checks, data scoping, webhook verification and secrets.

Each gap comes with a suggestion and a copyable prompt for your agent. For scoped .cursor/rules to go with it, grab the free Cursor Rules Pack. Starting from scratch? Use the AGENTS.md generator. The background is in Next.js 16 writes your AGENTS.md now.

02Skip the setup

A Next.js 16 SaaS starter that's already on proxy.ts.

Get the SaaS Starter Try the live demo

14-day money-back guarantee · lifetime updates

See everything that's inside →

AGENTS.md + CLAUDE.md · stack, commands, file locations and critical rules
Guardrails · server-side auth() checks, queries scoped to the user, raw-body webhook verification
Done means green · typecheck, lint, Vitest and build
Next.js 16.4.3 · next dev adds the managed block when an agent runs it

FAQ

What is the Next.js managed AGENTS.md block?

Since Next.js 16.3, next dev writes a block between  and  when it detects an AI coding agent. It points agents at version-matched docs in node_modules/next/dist/docs/. Next.js only updates the content between the markers.

Should I commit the managed block?

Yes. The Next.js docs say to commit it as-is. If you remove it, next dev adds it back, so it keeps showing up as an uncommitted change.

How do I turn it off?

Set agentRules: false in next.config.ts. Since Next.js 16.4.0, the next next dev run also removes the existing block and keeps the rest of the file.

Does this work for CLAUDE.md or non-Next.js projects?

Mostly. The stack, command and guardrail checks work on any agent instructions file. The managed-block check only applies to Next.js 16.3+.

Is my file sent anywhere?

No. The checks are plain JavaScript in this page. Nothing you paste is sent, logged or stored.

Sources: the Next.js AI agents guide, the agentRules reference, the Next.js 16.3 AI improvements post and generate-agent-files.js in Next.js 16.4.3. Checked Oct 27, 2026. Spotted a mistake? Email [email protected].

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