nextjs

A set of development standards for Next.js, a framework for building web applications with React. It covers project structure, page routing, layouts, data fetching, components, loading states, and error handling.

In plain words
What is it for?
Use it when creating or reviewing Next.js pages, routes, layouts, API handlers, reusable components, and shared hooks or services.
Why use it?
It gives a project consistent rules for organizing Next.js code and separating interface code from data and server work.

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/jimmypocock/cursor-rules/nextjs
Clone the repo
git clone --depth 1 https://github.com/jimmypocock/cursor-rules

Made for: Cursor.

Per session 5 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,014 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 $0.00005 $0.01014
Opus 5 $0.00003 $0.00507
Sonnet 5 $0.00001 $0.00203
Haiku 4.5 $0.00001 $0.00101

Measured 2d ago against content hash 6706c1cc404a, 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 · 152 lines

How it starts

The opening of the file, as written. The whole thing — 152 lines — stays where its author put it; the contents beside it link to each section on GitHub.


Description: Next.js Application Development Standards Globs: */.tsx, **/.ts, /pages//, /app//, /components//

Next.js Development Standards

@base.mdc @typescript.mdc

Project Structure

  • Use the App Router for new projects
  • Structure pages logically by feature or route
  • Create reusable components in a dedicated components directory
  • Group related functionality in feature directories
  • Use custom hooks for shared logic
  • Implement services for API interactions
  • Keep utility functions in a utils directory
  • Separate UI components from data fetching

App Router Best Practices

  • Use the folder-based routing system effectively
  • Implement layouts for shared UI across routes
  • Create loading and error states for each route
  • Use route groups for organizational purposes
  • Leverage parallel routes for complex layouts
  • Implement intercepting routes for modals and slideovers
  • Use dynamic segments for parameterized routes
  • Implement proper route handlers for API endpoints

Component Architecture

  • Use React Server Components by default
  • Mark client components with 'use client' directive when needed
  • Keep components focused on single responsibilities
  • Implement proper prop validation with TypeScript
  • Create reusable UI components in a component library
  • Leverage composition over inheritance
  • Implement proper error boundaries
  • Organize components by domain or feature

Data Fetching

  • Use React Server Components for server-side data fetching
  • Implement proper caching strategies
  • Leverage SWR or React Query for client-side data fetching
  • Handle loading and error states gracefully
  • Optimize fetch requests with appropriate cache headers
  • Implement pagination for large data sets
  • Use suspense boundaries for loading states
  • Implement proper error handling for failed requests

Performance Optimization

  • Use Image component for optimized images
  • Implement font optimization with next/font
  • Use dynamic imports for code splitting
  • Implement route prefetching for faster navigation
  • Optimize third-party scripts with Script component
  • Use React.memo for expensive components
  • Implement proper bundling strategies
  • Leverage Edge runtime for performance-critical paths

Read the full file on GitHub · 152 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. 2d ago First seen · 152 lines · 5 tokens per session scan A 6706c1cc404a

Subscribe to this mod's changes

nextjs is a cursor rule published in the GitHub repository jimmypocock/cursor-rules (8 stars, last pushed 1y ago), licensed MIT. It adds 5 tokens to every session and 1,014 once invoked, about $0.0000 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 2026-08-31.