React Specialist

React Specialist is an agent for coding agents from TheSethRose/Copilot-Skills. It costs 43 tokens per session (1,453 once invoked), scanned A, original, MIT.

A specialist profile for building applications with React, a JavaScript library for user interfaces. It covers component design, application state, performance, testing, accessibility, and related development patterns.

In plain words
What is it for?
Designing or reviewing React components, choosing state-management approaches, improving performance, and planning production React applications.
Why use it?
It gives React work a focused review of structure, speed, maintainability, and user-interface quality.

Agent

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/thesethrose/copilot-skills/react-specialist
Clone the repo
git clone --depth 1 https://github.com/TheSethRose/Copilot-Skills

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for React Specialist

README.md
[![agentmods](https://agentmods.dev/badge/agents/thesethrose/copilot-skills/react-specialist.svg)](https://agentmods.dev/agents/thesethrose/copilot-skills/react-specialist)
Your own site
<a href="https://agentmods.dev/agents/thesethrose/copilot-skills/react-specialist"><img src="https://agentmods.dev/badge/agents/thesethrose/copilot-skills/react-specialist.svg" alt="Measured on agentmods" height="20"></a>
Per session 43 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,453 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 $0.00043 $0.01453
Opus 5 $0.00022 $0.00727
Sonnet 5 $0.00009 $0.00291
Haiku 4.5 $0.00004 $0.00145

Measured 5d ago against content hash be01ef803761, 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 5d ago.

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

Copies of this mod

2 near-identical copies found in the catalogue:

.github/agents/react-specialist.md · 289 lines

How it starts

The opening of the file, as written. The whole thing — 289 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.

Prompt alignment:

  • When handling React/UI work, follow .github/prompts/react.skill.prompt.md in addition to these agent guidelines.

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 · 289 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. 5d ago First seen · 289 lines · 43 tokens per session scan A be01ef803761

Subscribe to this mod's changes

React Specialist is an agent published in the GitHub repository TheSethRose/Copilot-Skills (3 stars, last pushed 8mo ago), licensed MIT. It adds 43 tokens to every session and 1,453 once invoked, about $0.0002 per session on Opus 5. 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 2026-08-31.

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