A JavaScript library for building web interfaces from reusable pieces called components. It includes tools for component state, shared data, side effects, loading states, and controlling unnecessary re-renders.

Use it to build web pages and applications, manage changing interface data, connect components to external systems, show loading content, and organize shared state.

It breaks complex interfaces into smaller pieces that are easier to reason about, reuse, and update as application data changes.

react — Skill by hairyf

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/hairyf/skills/react

Any agent

npx skills add hairyf/skills --skill react

Clone the repo

git clone --depth 1 https://github.com/hairyf/skills

Made for: Claude Code, Codex.

Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,431 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. Scan, not verified.

Origin fork From a forked repository.

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.

Model	Per session	Once invoked
Fable 5	$0.00029	$0.01431
Opus 5	$0.00015	$0.00715
Sonnet 5	$0.00006	$0.00286
Haiku 4.5	$0.00003	$0.00143

Measured 2d ago against content hash 638fd94bbf71, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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 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.

skills/react/SKILL.md · 104 lines

How it starts

The opening of the file, as written. The whole thing — 104 lines — stays where its author put it; the contents beside it link to each section on GitHub.

React

The skill is based on React, generated at 2026-01-31.

React is a JavaScript library for building user interfaces. It lets you compose complex UIs from small and isolated pieces of code called "components". React uses a declarative paradigm that makes it easier to reason about your application and aims to be both efficient and flexible.

Core References

Topic	Description	Reference
useState	Hook for managing component state with direct updates	core-usestate
useEffect	Hook for synchronizing components with external systems	core-useeffect
useContext	Hook for reading and subscribing to context	core-usecontext
useRef	Hook for referencing values that don't trigger re-renders	core-useref
useReducer	Hook for managing complex state with a reducer function	core-usereducer
Suspense	Component for displaying fallback UI while content is loading	core-suspense
memo	Higher-order component for memoizing component renders	core-memo
createContext	API for creating context objects	core-createcontext
Fragment	Component for grouping elements without wrapper nodes	core-fragment
StrictMode	Component for enabling additional development checks	core-strictmode

Features

Performance Optimization

Topic	Description	Reference
useMemo	Hook for caching expensive calculations	features-usememo
useCallback	Hook for caching function definitions	features-usecallback
lazy	API for code splitting and lazy loading components	features-lazy
useTransition	Hook for non-blocking state updates	features-usetransition
useDeferredValue	Hook for deferring non-critical UI updates	features-usedeferredvalue
useLayoutEffect	Hook that fires synchronously before browser repaint	features-uselayouteffect
startTransition	API for marking non-blocking state updates	features-starttransition

Read the full file on GitHub · 104 lines

Files

What ships with it

37 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.

2d ago First seen · 104 lines · 29 tokens per session scan A 638fd94bbf71

Subscribe to this mod's changes

react is a skill published in the GitHub repository hairyf/skills (25 stars, last pushed 22d ago), licensed MIT. It adds 29 tokens to every session and 1,431 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It comes from a forked repository.

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