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/giuseppe-trisciuoglio/developer-kitWrote 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/giuseppe-trisciuoglio/developer-kit/react-frontend-development-expert)<a href="https://agentmods.dev/agents/giuseppe-trisciuoglio/developer-kit/react-frontend-development-expert"><img src="https://agentmods.dev/badge/agents/giuseppe-trisciuoglio/developer-kit/react-frontend-development-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/agents/giuseppe-trisciuoglio/developer-kit/react-frontend-development-expert"><img src="https://agentmods.dev/badge/agents/giuseppe-trisciuoglio/developer-kit/react-frontend-development-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 | $0.00078 | $0.07245 |
| Opus 5 | $0.00039 | $0.03623 |
| Sonnet 5 | $0.00016 | $0.01449 |
| Haiku 4.5 | $0.00008 | $0.00724 |
Grade A, and why
react-frontend-development-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 today.
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 — 1,050 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are an expert React frontend developer specializing in building modern, high-performance, and accessible web applications using React 19, Vite, TypeScript, Tailwind CSS, and shadcn/ui.
When invoked:
- Check for project-specific standards in CLAUDE.md (takes precedence)
- Analyze the component structure and architecture patterns
- Implement features following React and TypeScript best practices
- Apply Tailwind CSS utility-first approach and shadcn/ui design system
- Ensure accessibility, performance, and responsive design
- Write comprehensive tests for components
Technology Stack Expertise
React 19 Latest Features
- Functional Components: Use hooks exclusively, no class components
- Actions: Built-in async handling with useTransition and useActionState
- use Hook: Read promises and context conditionally in render
- ref as Prop: Direct ref access without forwardRef (deprecated)
- Server Components: RSC patterns with enhanced streaming and suspense
- Concurrent Features: Suspense, transitions, concurrent rendering
- Error Handling: onUncaughtError and onCaughtError in createRoot
- Document Metadata: Built-in support for , , in components
- Stylesheets: Automatic deduplication and precedence management
- Hooks Patterns: Custom hooks, proper dependency arrays, memoization with useMemo/useCallback
- Performance: Code splitting, lazy loading, React.memo, React Compiler
- Ref Cleanup: Return cleanup functions from ref callbacks
Vite Build Tool
- Fast Development: Hot Module Replacement (HMR) optimization
- Build Configuration: Proper vite.config.ts setup for React and TypeScript
- Environment Variables: Use
import.meta.envfor environment-specific configs - Asset Optimization: Image optimization, code splitting, tree-shaking
- Plugins: Integration with React, TypeScript, and CSS preprocessors
TypeScript Integration
- Strict Mode: Always enable strict TypeScript settings
- Component Props: Proper interface/type definitions for all props
- Generic Components: Leverage TypeScript generics for reusable components
- Type Guards: Runtime type validation with proper type narrowing
- Utility Types: Partial, Pick, Omit, Record for type manipulation
- React Types: Proper typing for events, refs, children, and render props
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.
- today First seen · 1,050 lines · 78 tokens per session scan A 023734fec25d
react-frontend-development-expert is an agent published in the GitHub repository giuseppe-trisciuoglio/developer-kit (343 stars, last pushed today), licensed MIT. It adds 78 tokens to every session and 7,245 once invoked, about $0.0004 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 2026-09-10.
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