React Doctor is a deterministic static analysis tool designed to identify security risks, performance regressions, and architectural anti-patterns in React and React Native codebases. Developed to assist developers in maintaining code quality, it functions as a specialized 'medical' diagnostic agent that catches issues often overlooked by standard linting configurations. The tool is designed to work seamlessly within modern development workflows, providing instant feedback both locally and during continuous integration processes.

Functionality is centered on a high-precision analysis engine that reviews codebases for common pitfalls such as unnecessary effect dependencies, potential state mutations, and accessibility errors. By leveraging deterministic analysis, it provides specific, actionable feedback on code quality issues rather than just generic lint warnings. It integrates with existing linting environments and respects standard ignore configurations, ensuring that developers can adopt it without disrupting their current tooling.

Some of the key features are:

• Automated Pull Request Review: Automatically scans changed files and posts inline review comments on problematic code, blocking regressions before they reach the main branch.
• Performance Analysis: Identifies bottlenecks including unnecessary useEffect hooks, suboptimal state updates, and performance-heavy patterns.
• Security Auditing: Detects potential security risks in client-side code, such as improper handling of secrets and dangerous patterns.
• Accessibility Support: Surfaces common accessibility regressions that can affect end-user experience.
• Customizable Blocking: Allows teams to configure the strictness of the gate, ranging from advisory mode to blocking CI/CD pipelines on errors.
• Framework Support: Offers native awareness for React, Next.js, Vite, TanStack, and React Native/Expo project structures.
• Health Score: Provides a quantifiable metric representing the overall health of the codebase, assisting in tracking long-term maintenance.
• Extensible Configuration: Supports custom configuration through files and plugins, allowing teams to tailor diagnostics to their specific architectural requirements.

React Doctor operates through a command-line interface and a GitHub Actions workflow. Developers can invoke it locally via npx react-doctor@latest to scan their current project, or set it up in CI to enforce code quality standards on every pull request. The tool intelligently parses the project's dependency graph, recognizes the framework-specific context, and flags issues based on their impact. The GitHub Action setup allows for sticky comments, ensuring that developers receive clear, concise summaries of their PR health, complete with links to documentation and concrete suggestions for remediation.

Some common use cases include:

• CI/CD Quality Gating: Preventing code that violates performance or security best practices from being merged into production branches.
• Automated Code Reviews: Assisting code reviewers by highlighting anti-patterns and performance issues in PRs automatically, allowing human reviewers to focus on business logic.
• AI Agent Guardrails: Using React Doctor as a tool for coding agents to ensure the code they generate adheres to strict quality and performance standards.
• Legacy Codebase Auditing: Assessing the health of existing projects to identify the most critical areas needing refactoring or optimization.