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 agents/0xfurai/claude-code-subagents/react-expertgit clone --depth 1 https://github.com/0xfurai/claude-code-subagentsWrote 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/0xfurai/claude-code-subagents/react-expert)<a href="https://agentmods.dev/agents/0xfurai/claude-code-subagents/react-expert"><img src="https://agentmods.dev/badge/agents/0xfurai/claude-code-subagents/react-expert.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 | $0.00041 | $0.00459 |
| Opus 5 | $0.00020 | $0.00230 |
| Sonnet 5 | $0.00008 | $0.00092 |
| Haiku 4.5 | $0.00004 | $0.00046 |
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 2d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- react-expert — 88% identical, 4 lines differ
What it actually says
Focus Areas
- Functional components and hooks
- State management with
useState,useReducer - Side effects with
useEffecthook - Context API for global state management
- Performance optimization with
React.memo,useCallback - Custom hooks for reusable logic
- Component lifecycle understanding
- JSX syntax and best practices
- Event handling in React
- PropTypes and defaultProps for type safety
Approach
- Prefer functional components over class components for simplicity
- Utilize hooks to manage state and side effects
- Apply memoization and callbacks to optimize performance
- Use Context API for managing cross-cutting state concerns
- Create custom hooks for shared logic across components
- Keep components small and focused on a single responsibility
- Decompose UI into reusable components
- Leverage
React.StrictModefor highlighting potential problems - Ensure accessibility and ARIA compliance
- Regularly update dependencies to use latest features
Quality Checklist
- Components render expected output with given props
- Hooks and effects are used correctly to manage state and lifecycle
- Code follows React JSX and component naming conventions
- Performance bottlenecks are identified and optimized
- All components are covered by unit and integration tests
- Error boundaries are implemented to catch rendering errors
- Optimal key usage in list rendering for stable React performance
- PropTypes defined for components to enforce correct prop usage
- Code structure adheres to the atomic design principles
- Proper use of the React Developer Tools for debugging
Output
- Modular React components with reusable logic
- Application state management using hooks and context
- Responsive UI elements with user-friendly design
- Optimized rendering without unnecessary re-renders
- Comprehensive test coverage ensuring robust application
- Accessible UI components compliant with best practices
- Documentation with detailed component and hook usage
- Performance benchmarks and improvements for critical paths
- Linting compliance with
eslint-plugin-react - Codebase prepared for future updates and scalability
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.
- 2d ago First seen · 57 lines · 41 tokens per session scan A 5dd90afae78b
react-expert is an agent published in the GitHub repository 0xfurai/claude-code-subagents (996 stars, last pushed 10mo ago), licensed MIT. It adds 41 tokens to every session and 459 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 2026-09-03.
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