What AGENTS.md is in a Next.js SaaS kit
AGENTS.md is a markdown file at the root of a repo that tells coding agents how to work in this codebase. It is not a product feature users click. It is not a model. It is the brief you wish the intern read before opening a pull request.
Other kits ship one too. Supastarter in particular has been loud about AGENTS.md and skills. The file is becoming table stakes. The useful question is what it should contain for a Next.js SaaS, not whether the filename exists.
What belongs in AGENTS.md
Keep it operational. Agents already know generic React. They do not know your doors:
- Stack. Next.js App Router, Supabase, Stripe, Resend. Do not let the agent add a second auth library "to be helpful."
- Roles. Owner holds billing. Admins invite. Members use the app. Do not invent seat billing in a random route.
- Security habits. Gate every API route. Do not write the database from the browser for privileged work. Do not log tokens. Do not compute prices on the client.
- Skills inventory. Point at the SKILL.md files that already encode copy, SEO, schema, Postgres, and email. Skills are the long form. AGENTS.md is the index.
If the file is a marketing paragraph with no paths, the agent will ignore it. If it is a dump of every convention, the agent will miss the few that prevent a second Stripe integration.
How this differs from a Cursor rule
Cursor rules and Claude skills are scoped. AGENTS.md is the repo handshake: "read this first, then load the skill that matches the task." A copywriting skill should not also explain RLS. The root file should say where billing lives so a landing-page edit does not spawn a new checkout route.
NextBento puts that index in the product repo you clone. The marketing site you are reading is a separate repo. Do not copy live comparison pages into the kit's demo pages.json. That split is also in AGENTS.md on purpose.
What it does not replace
AGENTS.md will not design your product. It will not verify that a user paid. It will not stop a bad prompt from deleting a migration if you skip review. Treat it like a senior's onboarding doc: high leverage when the codebase is already coherent, useless as a substitute for that codebase.
If you are still prompting auth and Stripe from an empty folder, write the file after you have a foundation, or start from a kit that already has one. The longer version of that argument is prompting from a blank repo. Audience intent for Cursor-first founders lives on NextBento for AI-assisted founders.
