react

Rules for building React user interfaces with function-based components and hooks, which are React features for managing reusable behavior and state.

In plain words
What is it for?
Use them when creating JSX or TSX components, reusable hooks, shared state with Context, validated props, lists, and performance-sensitive components.
Why use it?
They provide consistent ways to share logic, manage state, render lists safely, validate inputs, and avoid unnecessary page elements or updates.

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/rm2thaddeus/pixel_detective/react
Clone the repo
git clone --depth 1 https://github.com/rm2thaddeus/Pixel_Detective

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 131 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 $0.00131
Opus 5 $0.00000 $0.00066
Sonnet 5 $0.00000 $0.00026
Haiku 4.5 $0.00000 $0.00013

Measured yesterday against content hash bf51fb64e200, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

react 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 yesterday.

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/react.mdc · 23 lines

What it actually says


description: This rule explains React component patterns, hooks usage, and best practices. globs: /*.jsx,/*.tsx alwaysApply: false

React rules

  • Use functional components with hooks instead of class components
  • Use custom hooks for reusable logic
  • Use the Context API for state management when needed
  • Use proper prop validation with PropTypes
  • Use React.memo for performance optimization when necessary
  • Use fragments to avoid unnecessary DOM elements
  • Use proper list rendering with keys
  • Prefer composition over inheritance
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. yesterday First seen · 23 lines · 131 tokens per session scan A bf51fb64e200

Subscribe to this mod's changes

react is a cursor rule published in the GitHub repository rm2thaddeus/Pixel_Detective (21 stars, last pushed 6mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 131 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.