mcpbeat

React Doctor

posthog/react-doctor

Diagnose and fix React codebase health issues. Use when reviewing React code, fixing performance problems, auditing security, or improving code quality.

370 tokens
context cost
the whole folder, loaded on every use
1
files
instructions only
0
copies elsewhere
how many repositories repackaged it
690
stars on the repo
on the repository, not the skill itself

Install

one command, takes just this skill from the repository 
npx skills add https://github.com/PostHog/posthog --skill react-doctor

The instruction itself

5 sections, as written by the author

React Doctor

Scans your React codebase for security, performance, correctness, and architecture issues. Outputs a 0-100 score with actionable diagnostics.

Usage

npx -y react-doctor@latest . --verbose

Workflow

  • Run the command above at the project root
  • Read every diagnostic with file paths and line numbers
  • Fix issues starting with errors (highest severity)
  • Re-run to verify the score improved

Rules (47+)

  • Security: hardcoded secrets in client bundle, eval()
  • State & Effects: derived state in useEffect, missing cleanup, useState from props, cascading setState
  • Architecture: components inside components, giant components, inline render functions
  • Performance: layout property animations, transition-all, large blur values
  • Correctness: array index as key, conditional rendering bugs
  • Next.js: missing metadata, client-side fetching for server data, async client components
  • Bundle Size: barrel imports, full lodash, moment.js, missing code splitting
  • Server: missing auth in server actions, blocking without after()
  • Accessibility: missing prefers-reduced-motion
  • Dead Code: unused files, exports, types

Score

  • 75+: Great
  • 50-74: Needs work
  • 0-49: Critical

How to use it

Copy the folder

Take posthog/react-doctor from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.

Install what it needs

The instructions reference npx. Without those the skill loads but fails at the first command.