Borrowing it
Nothing to install: this file belongs to antosubash/SimpleModule. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/antosubash/SimpleModule/main/.claude/skills/react-expert/SKILL.mdgit clone --depth 1 https://github.com/antosubash/SimpleModuleWrote 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/skills/antosubash/simplemodule/react-expert)<a href="https://agentmods.dev/skills/antosubash/simplemodule/react-expert"><img src="https://agentmods.dev/badge/skills/antosubash/simplemodule/react-expert/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/skills/antosubash/simplemodule/react-expert"><img src="https://agentmods.dev/badge/skills/antosubash/simplemodule/react-expert.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 | $0.00079 | $0.01199 |
| Opus 5.5 | $0.00032 | $0.00480 |
| Sonnet 5.5 | $0.00016 | $0.00240 |
| Haiku 4.5 | $0.00008 | $0.00120 |
Grade A, and why
react-expert 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 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.
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.
This is a copy
95% identical to react-expert — 5 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.
How it starts
The opening of the file, as written. The whole thing — 150 lines — stays where its author put it; the contents beside it link to each section on GitHub.
React Expert
Senior React specialist with deep expertise in React 19, Server Components, and production-grade application architecture.
When to Use This Skill
- Building new React components or features
- Implementing state management (local, Context, Redux, Zustand)
- Optimizing React performance
- Setting up React project architecture
- Working with React 19 Server Components
- Implementing forms with React 19 actions
- Data fetching patterns with TanStack Query or
use()
Core Workflow
- Analyze requirements - Identify component hierarchy, state needs, data flow
- Choose patterns - Select appropriate state management, data fetching approach
- Implement - Write TypeScript components with proper types
- Validate - Run
tsc --noEmit; if it fails, review reported errors, fix all type issues, and re-run until clean before proceeding - Optimize - Apply memoization where needed, ensure accessibility; if new type errors are introduced, return to step 4
- Test - Write tests with React Testing Library; if any assertions fail, debug and fix before submitting
Reference Guide
Load detailed guidance based on context:
| Topic | Reference | Load When |
|---|---|---|
| Server Components | references/server-components.md |
RSC patterns, Next.js App Router |
| React 19 | references/react-19-features.md |
use() hook, useActionState, forms |
| State Management | references/state-management.md |
Context, Zustand, Redux, TanStack |
| Hooks | references/hooks-patterns.md |
Custom hooks, useEffect, useCallback |
| Performance | references/performance.md |
memo, lazy, virtualization |
| Testing | references/testing-react.md |
Testing Library, mocking |
| Class Migration | references/migration-class-to-modern.md |
Converting class components to hooks/RSC |
Key Patterns
Server Component (Next.js App Router)
// app/users/page.tsx — Server Component, no "use client"
import { db } from '@/lib/db';
interface User {
id: string;
name: string;
}
export default async function UsersPage() {
const users: User[] = await db.user.findMany();
return (
<ul>
{users.map((user) => (
<li key={user.id}>{user.name}</li>
))}
</ul>
);
}
What ships with it
6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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 · 150 lines · 79 tokens per session scan A f349e26b8743
react-expert is a skill published in the GitHub repository antosubash/SimpleModule (5 stars, last pushed 17d ago), licensed MIT. It adds 79 tokens to every session and 1,199 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 95% identical to react-expert, differing in 5 lines, and is treated as a copy.
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