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Frontend DevelopmentPostHog

react-doctor

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

Stars
34,779
Source
PostHog/posthog
Updated
2026-05-31
Slug
PostHog--posthog--react-doctor
View on GitHubRaw SKILL.md

// install — copy + paste into any project

mkdir -p .claude/skills && curl -fsSL https://raw.githubusercontent.com/PostHog/posthog/HEAD/.agents/skills/react-doctor/SKILL.md -o .claude/skills/react-doctor.md

Drops the SKILL.md into .claude/skills/react-doctor.md. Works with Claude Code, Cursor, and any agent that loads SKILL.md files from .claude/skills/.

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

  1. Run the command above at the project root
  2. Read every diagnostic with file paths and line numbers
  3. Fix issues starting with errors (highest severity)
  4. 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