next

A project rule set for Next.js, a framework for building web applications with React. It uses the installed version's documentation and checks whether the project uses the App Router or Pages Router.

In plain words
What is it for?
It guides data loading, request headers and cookies, environment variables, package installation, router-specific code, and version-appropriate changes.
Why use it?
It reduces errors caused by guessing APIs, mixing the two routing systems, or applying rules from a different Next.js version.

Cursor rule

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.

agentmods
npx agentmods add rules/kleosr/kleosrules/next
Clone the repo
git clone --depth 1 https://github.com/kleosr/kleosrules
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 361 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00000 $0.00361
Opus 5 $0.00000 $0.00180
Sonnet 5 $0.00000 $0.00072
Haiku 4.5 $0.00000 $0.00036

Measured 2d ago against content hash fb197fcbd9b9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

next 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 2d 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.

shared/rules/next.mdc · 24 lines

What it actually says

Next.js

This is not the Next in training. Before Write, Read the matching guide under node_modules/next/dist/docs/ from this app's package (monorepos: not the repo root if next is nested). Heed deprecations.

If that folder is missing: Next <16.2. Use project AGENTS.md / .next-docs/ or npx @next/codemod@canary agents-md. Do not guess APIs.

Detect router from the tree: app/ → App Router only. pages/ without app/ → Pages only. Never mix.

Hard

  • Fetch in Server Components. No useEffect for initial server data.
  • cookies() / headers(): follow this version's docs (often async).
  • No getServerSideProps / getStaticProps in app/. No next/navigation in Pages.
  • No Vite import.meta.env for Next public env; use process.env as this version documents.
  • Knowledge from bundled docs, not from a Next "knowledge skill". Skills like next-dev-loop are workflows only.

pnpm for installs. Subagents inherit this.

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. 2d ago First seen · 24 lines · 0 tokens per session scan A fb197fcbd9b9

Subscribe to this mod's changes

next is a cursor rule published in the GitHub repository kleosr/kleosrules (2 stars, last pushed 2d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 361 tokens. 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 2026-08-31.