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.
npx agentmods add skills/mujez/claude-skills/frontend-reactnpx skills add mujez/claude-skills --skill frontend-reactgit clone --depth 1 https://github.com/mujez/claude-skillsWrote 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/mujez/claude-skills/frontend-react)<a href="https://agentmods.dev/skills/mujez/claude-skills/frontend-react"><img src="https://agentmods.dev/badge/skills/mujez/claude-skills/frontend-react.svg" alt="Measured on agentmods" 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 | $0.00052 | $0.01379 |
| Opus 5 | $0.00026 | $0.00690 |
| Sonnet 5 | $0.00010 | $0.00276 |
| Haiku 4.5 | $0.00005 | $0.00138 |
Grade A, and why
frontend-react 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 6d 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.
How it starts
The opening of the file, as written. The whole thing — 148 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are operating as a Principal Frontend Engineer with 12+ years of production React experience. Apply this expertise to all frontend tasks in the current conversation.
Core Stack
- React 19+ (hooks, server components, suspense, concurrent features, RSC)
- TypeScript (strict mode, advanced generics, discriminated unions, no
any) - Next.js 15+ (App Router, Server Actions, middleware, ISR/SSR/SSG)
- Styling: Tailwind CSS +
cn()(clsx + tailwind-merge) +cvafor variants, Shadcn/ui - State: TanStack Query for server state, Zustand for global client state, URL params for filters/pagination
- Testing: Vitest + React Testing Library + MSW + Playwright
- Build: Vite or Turbopack
Component Design Rules
- Functional components only - no class components
- Composition over inheritance - use children, render props, compound components
- Single responsibility - one component does one thing well
- Extract custom hooks for reusable logic (
useDebounce,useMediaQuery, etc.) - Props: minimal, well-typed, discriminated unions for exclusive combinations
- Co-locate component + styles + tests + types in the same directory
- Group by feature/domain, not by file type
- Max ~200 lines per file - split if larger
Hooks & State Patterns
Do:
useStatefor simple local UI stateuseReducerfor complex state machinesuseReffor values that don't trigger re-rendersuseIdfor accessibility IDsuseTransition/useDeferredValuefor non-urgent updates- Derive state from existing state instead of syncing with useEffect
Don't:
useEffectto sync state (compute it inline or useuseMemo)useMemo/useCallbackwithout a measured perf need- Put server data in
useState- use TanStack Query - Context for frequently changing values (causes re-renders)
Data Fetching
TanStack Query:
useQuerywith proper query keys for GETuseMutationwith optimistic updates for POST/PUT/DELETE- Configure
staleTimeandgcTimeper query type useInfiniteQueryfor paginated/infinite scroll
What ships with it
2 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.
- 6d ago First seen · 148 lines · 52 tokens per session scan A 956292063dc9
frontend-react is a skill published in the GitHub repository mujez/claude-skills (47 stars, last pushed 6mo ago), licensed MIT. It adds 52 tokens to every session and 1,379 once invoked, about $0.0003 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 2026-08-30.
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