nextjs

A set of coding rules for building Next.js websites with TypeScript and Tailwind CSS. Next.js is a framework for web applications, while TypeScript adds type checking and Tailwind CSS provides utility-based styling.

In plain words
What is it for?
Use it when structuring an App Router project, choosing server or browser-side components, loading data, optimizing images, and handling loading or error states.
Why use it?
It helps keep pages, components, data loading, routing, errors, and performance work consistent in a Next.js project.

Cursor rule for Cursor

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/agentset-ai/agentset/nextjs
Clone the repo
git clone --depth 1 https://github.com/agentset-ai/agentset

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 418 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 $0.00418
Opus 5 $0.00000 $0.00209
Sonnet 5 $0.00000 $0.00084
Haiku 4.5 $0.00000 $0.00042

Measured 2d ago against content hash 7b9b7972f454, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

nextjs 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.

.cursor/rules/nextjs.mdc · 63 lines

What it actually says

Next.js Best Practices

Project Structure

  • Use the App Router directory structure
  • Place components in app directory for route-specific components
  • Place shared components in components directory
  • Place utilities and helpers in lib directory
  • Use lowercase with dashes for directories (e.g., components/auth-wizard)

Components

  • Use Server Components by default
  • Mark client components explicitly with 'use client'
  • Wrap client components in Suspense with fallback
  • Use dynamic loading for non-critical components
  • Implement proper error boundaries
  • Place static content and interfaces at file end

Performance

  • Optimize images: Use WebP format, size data, lazy loading
  • Minimize use of 'useEffect' and 'setState'
  • Favor Server Components (RSC) where possible
  • Use dynamic loading for non-critical components
  • Implement proper caching strategies

Data Fetching

  • Use Server Components for data fetching when possible
  • Implement proper error handling for data fetching
  • Use appropriate caching strategies
  • Handle loading and error states appropriately

Routing

  • Use the App Router conventions
  • Implement proper loading and error states for routes
  • Use dynamic routes appropriately
  • Handle parallel routes when needed
  • Whenever you need to use useRouter, import it like this import { useRouter } from "@bprogress/next/app"; to show global proggress bar

Forms and Validation

  • Use Zod for form validation
  • Use react-hook-form for form handling defined in form.tsx
  • Implement proper server-side validation
  • Handle form errors appropriately
  • Show loading states during form submission

State Management

  • Minimize client-side state
  • Use React Context sparingly
  • Prefer server state when possible
  • Implement proper loading states
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 · 63 lines · 0 tokens per session scan A 7b9b7972f454

Subscribe to this mod's changes

nextjs is a cursor rule published in the GitHub repository agentset-ai/agentset (2,076 stars, last pushed 1mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 418 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 2026-08-30.