react-expert

react-expert is a skill for Claude Code, Codex from kaustubhhiware/agent-skills-fullstack-development. It costs 40 tokens per session (770 once invoked), scanned A, original, MIT.

A set of instructions for building React 18 and newer web applications. React is a JavaScript library for creating user interfaces from reusable components.

In plain words
What is it for?
Use it when creating React components and features, setting up project structure, adding state management or data fetching, building forms, improving performance, or writing interface tests.
Why use it?
It helps choose how components share data, manage state, load information, handle forms, and stay accessible and responsive as an application grows.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/kaustubhhiware/agent-skills-fullstack-development/react-expert
Any agent
npx skills add kaustubhhiware/agent-skills-fullstack-development --skill react-expert
Clone the repo
git clone --depth 1 https://github.com/kaustubhhiware/agent-skills-fullstack-development

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for react-expert

README.md
[![agentmods](https://agentmods.dev/badge/skills/kaustubhhiware/agent-skills-fullstack-development/react-expert.svg)](https://agentmods.dev/skills/kaustubhhiware/agent-skills-fullstack-development/react-expert)
Your own site
<a href="https://agentmods.dev/skills/kaustubhhiware/agent-skills-fullstack-development/react-expert"><img src="https://agentmods.dev/badge/skills/kaustubhhiware/agent-skills-fullstack-development/react-expert.svg" alt="Measured on agentmods" height="20"></a>
Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 770 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00040 $0.00770
Opus 5 $0.00020 $0.00385
Sonnet 5 $0.00008 $0.00154
Haiku 4.5 $0.00004 $0.00077

Measured 4d ago against content hash b3cd6ede0b97, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 4d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

.agents/skills/react-expert/SKILL.md · 85 lines

How it starts

The opening of the file, as written. The whole thing — 85 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.

Role Definition

You are a senior React engineer with 10+ years of frontend experience. You specialize in React 19 patterns including Server Components, the use() hook, and form actions. You build accessible, performant applications with TypeScript and modern state management.

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

  1. Analyze requirements - Identify component hierarchy, state needs, data flow
  2. Choose patterns - Select appropriate state management, data fetching approach
  3. Implement - Write TypeScript components with proper types
  4. Optimize - Apply memoization where needed, ensure accessibility
  5. Test - Write tests with React Testing Library

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

Constraints

MUST DO

  • Use TypeScript with strict mode
  • Implement error boundaries for graceful failures
  • Use key props correctly (stable, unique identifiers)
  • Clean up effects (return cleanup function)
  • Use semantic HTML and ARIA for accessibility
  • Memoize when passing callbacks/objects to memoized children
  • Use Suspense boundaries for async operations

Read the full file on GitHub · 85 lines

Files

What ships with it

7 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.

Changes

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.

  1. 4d ago First seen · 85 lines · 40 tokens per session scan A b3cd6ede0b97

Subscribe to this mod's changes

react-expert is a skill published in the GitHub repository kaustubhhiware/agent-skills-fullstack-development (16 stars, last pushed 3mo ago), licensed MIT. It adds 40 tokens to every session and 770 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 2026-08-30.

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