react-19 skillA
react-19 is agent-read markdown (skill) from fusengine/agents: Use when implementing React 19.2 patterns — use(), useOptimistic, useActionState, useEffectEvent, Activity component, React Compiler..
Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.
What the file says
<objective>
Covers React 19.2's new hooks and features: `use()` for reading promises/context in render, `useOptimistic` for instant UI updates, `useActionState` for form action state, `useFormStatus` for child-component pending state, `useEffectEvent` for non-reactive effect callbacks, the `Activity` component for hiding/showing UI while preserving state, and the React Compiler's automatic memoization (making manual `useMemo`/`useCallback` mostly obsolete).
Also documents all classic hooks (useState, useEffect, useLayoutEffect, useRef, useImperativeHandle, useMemo, useCallback, useId, useSyncExternalStore) and React 18→19 breaking changes (`ref` as a prop instead of `forwardRef`, `<Context value={}>` instead of `<Context.Provider>`). This is the core React hooks/features skill — for global state see react-state, for forms see react-forms, and for SOLID architecture rules see solid-react.
</objective>
# React 19.2 Core Features
## Agent Workflow (MANDATORY)
Before ANY implementation, spawn 3 agents in parallel, one `Agent` call each with a `name`:
1. **fuse-ai-pilot:explore-codebase** - Analyze existing React patterns and component structure
…Read the whole file at its exact version.
How to install
mdr add fusengine/agents/react-19@v19.2.0mdr add fusengine/agents/react-19@sha256:f27b298edc554b5aPin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.
[](https://markdownregistry.com/a/art_lubqrcexd6tyz6ss)
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Versions
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| v19.2.0 latest | 2026-09-04 | 5f1d30f | 8,936 B | A | view · diff |
| v19.2.0 | 2026-07-29 | 3b91eed | 8,907 B | A | view · diff |
| v19.2.0 | 2026-02-07 | 0a3cd21 | 8,004 B | A | view · diff |
| v19.2.0 | 2026-01-31 | 9cb1933 | 6,999 B | A | view · diff |
| v19.2.0 | 2026-01-31 | 7d8568c | 7,988 B | A | view |
Audit of the latest version
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- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (8936 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
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- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
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- pass: No base64 blob over 200 characters
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- pass: No script tag
Source
fusengine/agents · 28 stars · license MIT · pushed 2026-09-24 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_lubqrcexd6tyz6ss GET https://markdownregistry.com/api/v1/resolve?ref=fusengine/agents/react-19 GET https://markdownregistry.com/api/v1/blob/f27b298edc554b5ae82d5e5d4a0c126c256b3d6278b964169975218b6e44f1ec
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