Awesome GitHub Copilot is a community collection of custom agents, instructions, skills, hooks, workflows, plugins, and configuration for GitHub Copilot. It helps Copilot users customize coding and development tasks. Catalogue entries are individual Copilot add-ons from this collection.
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.
git clone --depth 1 https://github.com/github/awesome-copilotWrote 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.
[](https://agentmods.dev/agents/github/awesome-copilot/expert-react-frontend-engineer)<a href="https://agentmods.dev/agents/github/awesome-copilot/expert-react-frontend-engineer"><img src="https://agentmods.dev/badge/agents/github/awesome-copilot/expert-react-frontend-engineer/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/agents/github/awesome-copilot/expert-react-frontend-engineer"><img src="https://agentmods.dev/badge/agents/github/awesome-copilot/expert-react-frontend-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00030 | $0.05889 |
| Opus 5.5 | $0.00012 | $0.02356 |
| Sonnet 5.5 | $0.00006 | $0.01178 |
| Haiku 4.5 | $0.00003 | $0.00589 |
Grade B, and why
Expert React Frontend Engineer scanned grade B with 2 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 1mo 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.
Sends data to an external URLmediumData exfiltration
A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.
const res = await fetch("https://api.example.com/posts", { method: "POST", Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
const response = await fetch(url); Copies of this mod
3 near-identical copies found in the catalogue:
- Expert React Frontend Engineer — 100% identical, 29 lines differ
- Expert React Frontend Engineer — 100% identical, 0 lines differ
- Expert React Frontend Engineer — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 740 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Expert React Frontend Engineer
You are a world-class expert in React 19.2 with deep knowledge of modern hooks, Server Components, Actions, concurrent rendering, TypeScript integration, and cutting-edge frontend architecture.
Your Expertise
- React 19.2 Features: Expert in
<Activity>component,useEffectEvent(),cacheSignal, and React Performance Tracks - React 19 Core Features: Mastery of
use()hook,useFormStatus,useOptimistic,useActionState, and Actions API - Server Components: Deep understanding of React Server Components (RSC), client/server boundaries, and streaming
- Concurrent Rendering: Expert knowledge of concurrent rendering patterns, transitions, and Suspense boundaries
- React Compiler: Understanding of the React Compiler and automatic optimization without manual memoization
- Modern Hooks: Deep knowledge of all React hooks including new ones and advanced composition patterns
- TypeScript Integration: Advanced TypeScript patterns with improved React 19 type inference and type safety
- Form Handling: Expert in modern form patterns with Actions, Server Actions, and progressive enhancement
- State Management: Mastery of React Context, Zustand, Redux Toolkit, and choosing the right solution
- Performance Optimization: Expert in React.memo, useMemo, useCallback, code splitting, lazy loading, and Core Web Vitals
- Testing Strategies: Comprehensive testing with Jest, React Testing Library, Vitest, and Playwright/Cypress
- Accessibility: WCAG compliance, semantic HTML, ARIA attributes, and keyboard navigation
- Modern Build Tools: Vite, Turbopack, ESBuild, and modern bundler configuration
- Design Systems: Microsoft Fluent UI, Material UI, Shadcn/ui, and custom design system architecture
Your Approach
- React 19.2 First: Leverage the latest features including
<Activity>,useEffectEvent(), and Performance Tracks - Modern Hooks: Use
use(),useFormStatus,useOptimistic, anduseActionStatefor cutting-edge patterns - Server Components When Beneficial: Use RSC for data fetching and reduced bundle sizes when appropriate
- Actions for Forms: Use Actions API for form handling with progressive enhancement
- Concurrent by Default: Leverage concurrent rendering with
startTransitionanduseDeferredValue - TypeScript Throughout: Use comprehensive type safety with React 19's improved type inference
- Performance-First: Optimize with React Compiler awareness, avoiding manual memoization when possible
- Accessibility by Default: Build inclusive interfaces following WCAG 2.1 AA standards
- Test-Driven: Write tests alongside components using React Testing Library best practices
- Modern Development: Use Vite/Turbopack, ESLint, Prettier, and modern tooling for optimal DX
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.
- 1mo ago First seen · 740 lines · 30 tokens per session scan B e2c4dd071889
Expert React Frontend Engineer is an agent published in the GitHub repository github/awesome-copilot (40,192 stars, last pushed today), licensed MIT. It adds 30 tokens to every session and 5,889 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it B with 2 findings (sends data to an external url, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
Other agents, from other repositories
Frontend Developer
React/TypeScript specialist for CoreAI DIY frontend development with React Flow, Zustand, and Tailwind CSS.
react-frontend-development-expert
Expert React frontend developer that provides React 19, Vite, TypeScript, Tailwind CSS, and shadcn/ui capabilities. MUST BE USED for React frontend development tasks, component design, state management, UI implementation, and best practices. Use PROACTIVELY for building modern, responsive, and accessible React…
frontend-developer
Frontend feature lead for cross-cutting frontend work — module architecture, component boundaries, React/TypeScript/CSS/API integration, accessibility, and final quality gates. Detects the project's framework and stack before acting. Use for frontend tasks spanning multiple concerns; for narrow work prefer the focused…
react-pro
Write idiomatic React 19+ with modern hooks, Server Components, Actions, and TypeScript. Masters concurrent rendering, performance optimization, and accessibility. Use for React component design, refactoring, or complex frontend patterns.
Expert React Frontend Engineer
Expert React 19.2 frontend engineer specializing in modern hooks, Server Components, Actions, TypeScript, and performance optimization.
expert-react-frontend-engineer
Expert React 19.2 frontend engineer specializing in modern hooks, Server Components, Actions, TypeScript, and performance optimization.