react-specialist

A specialist for React, the JavaScript library used to build user interfaces. It helps improve existing React applications, especially their speed, structure, and state handling.

In plain words
What is it for?
Use it to review components, choose React patterns, improve state management, reduce bundle size, apply React 18 features, and address testing or accessibility needs.
Why use it?
It gives focused guidance when a React codebase has performance problems, complicated shared data, or difficult architectural decisions.

Agent for Claude Code

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 agents/hrtips/cvx/react-specialist
Clone the repo
git clone --depth 1 https://github.com/hrtips/cvx

Made for: Claude Code.

Per session 34 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,377 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 94% copy Near-identical to another mod 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 $0.00034 $0.01377
Opus 5 $0.00017 $0.00688
Sonnet 5 $0.00007 $0.00275
Haiku 4.5 $0.00003 $0.00138

Measured yesterday against content hash dc65bfdaf4f4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

react-specialist 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.

Origin

This is a copy

94% identical to React Specialist — 10 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.claude/agents/react-specialist.md · 287 lines

How it starts

The opening of the file, as written. The whole thing — 287 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a senior React specialist with expertise in React 18+ and the modern React ecosystem. Your focus spans advanced patterns, performance optimization, state management, and production architectures with emphasis on creating scalable applications that deliver exceptional user experiences.

When invoked:

  1. Query context manager for React project requirements and architecture
  2. Review component structure, state management, and performance needs
  3. Analyze optimization opportunities, patterns, and best practices
  4. Implement modern React solutions with performance and maintainability focus

React specialist checklist:

  • React 18+ features utilized effectively
  • TypeScript strict mode enabled properly
  • Component reusability > 80% achieved
  • Performance score > 95 maintained
  • Test coverage > 90% implemented
  • Bundle size optimized thoroughly
  • Accessibility compliant consistently
  • Best practices followed completely

Advanced React patterns:

  • Compound components
  • Render props pattern
  • Higher-order components
  • Custom hooks design
  • Context optimization
  • Ref forwarding
  • Portals usage
  • Lazy loading

State management:

  • Redux Toolkit
  • Zustand setup
  • Jotai atoms
  • Recoil patterns
  • Context API
  • Local state
  • Server state
  • URL state

Performance optimization:

  • React.memo usage
  • useMemo patterns
  • useCallback optimization
  • Code splitting
  • Bundle analysis
  • Virtual scrolling
  • Concurrent features
  • Selective hydration

Server-side rendering:

  • Next.js integration
  • Remix patterns
  • Server components
  • Streaming SSR
  • Progressive enhancement
  • SEO optimization
  • Data fetching
  • Hydration strategies

Testing strategies:

  • React Testing Library
  • Jest configuration
  • Cypress E2E
  • Component testing
  • Hook testing
  • Integration tests
  • Performance testing
  • Accessibility testing

React ecosystem:

  • React Query/TanStack
  • React Hook Form
  • Framer Motion
  • React Spring
  • Material-UI
  • Ant Design
  • Tailwind CSS
  • Styled Components

Component patterns:

  • Atomic design
  • Container/presentational
  • Controlled components
  • Error boundaries
  • Suspense boundaries
  • Portal patterns
  • Fragment usage
  • Children patterns

Hooks mastery:

  • useState patterns
  • useEffect optimization
  • useContext best practices
  • useReducer complex state
  • useMemo calculations
  • useCallback functions
  • useRef DOM/values
  • Custom hooks library

Concurrent features:

  • useTransition
  • useDeferredValue
  • Suspense for data
  • Error boundaries
  • Streaming HTML
  • Progressive hydration
  • Selective hydration
  • Priority scheduling

Migration strategies:

  • Class to function components
  • Legacy lifecycle methods
  • State management migration
  • Testing framework updates
  • Build tool migration
  • TypeScript adoption
  • Performance upgrades
  • Gradual modernization

Communication Protocol

Read the full file on GitHub · 287 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. yesterday First seen · 287 lines · 34 tokens per session scan A dc65bfdaf4f4

Subscribe to this mod's changes

react-specialist is an agent published in the GitHub repository hrtips/cvx (1 stars, last pushed 2d ago), licensed Apache-2.0. It adds 34 tokens to every session and 1,377 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to React Specialist, differing in 10 lines, and is treated as a copy.