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React Best Practices Agent Skill

React performance optimization and best practices.

Install this skill Read the source first Free Written by davidanthonyn
Context cost
37k tokensestimated from the bundle, loaded when it triggers
Bundle
44 files · 154.0 kB3 scripts among them — read before you run
Licence
Apache-2.0the author’s own terms
Last change
—v1.8.0
Servers it uses
Noneruns standalone

What it does

React performance optimization and best practices. ALWAYS use this skill when working with any React code - writing components, hooks, JSX; refactoring; optimizing re-renders, memoization, state management; reviewing for performance; fixing hydration mismatches; debugging infinite re-renders, stale closures, input focus loss, animations restarting; preventing remounting; implementing transitions, lazy initialization, effect dependencies. Even simple React tasks benefit from these patterns. Covers React 19+ (useEffectEvent, Activity, ref props).

What this skill changes about the agent has not been set out here as a list. Its SKILL.md, shown below, says it in the author’s own words.

developer toolsperformancereact
Filed under

Developer Tools & Repos

The skill itself

A skill is instructions the model reads, so you can see what you are getting: below is the start of its SKILL.md. The front matter loads with every session, the body loads when the skill triggers, and the whole file comes with the install.

SKILL.md11.6 kB · preview
--- name: accelint-react-best-practices license: Apache-2.0 metadata: author: accelint version: "1.8.0" ---
10# React Best Practices
11
12Comprehensive performance optimization and best practices for React applications, designed for AI agents and LLMs working with React code.
13
14## NEVER Do React
15
16These are the most critical anti-patterns that cause real production issues. Experts learned these the hard way through debugging sessions and performance investigations.
17
18**NEVER define components inside components** — creates new component type on every render, causing full remount with state loss and DOM recreation. Results in input fields losing focus on keystroke, animations restarting unexpectedly, and useEffect cleanup/setup running on every parent render.
19
20**NEVER subscribe to searchParams/localStorage if you only read them in callbacks** — causes component to re-render on every URL change or storage event even when the component doesn't display those values. Read directly in the callback instead: new URLSearchParams(window.location.search).
21
22**NEVER use object/array dependencies in useEffect** — triggers effect on every render since objects are recreated with new references each time. Extract primitive values (id, name) from objects and use those as dependencies instead.
23
24**NEVER sync derived state with useState + useEffect** — leads to extra re-renders, infinite loops, and stale intermediate states. Calculate derived values during render instead: const fullName = firstName + ' ' + lastName.
25
26**NEVER use client-only state (localStorage, cookies, device detection) directly in SSR components** — causes hydration mismatches where server HTML doesn't match client render, resulting in React warnings, visual flickering, and broken interactivity. Use synchronous inline <script> before React hydrates.
27
28**NEVER use forwardRef in React 19+** — deprecated API. Use ref as a regular prop instead: function MyInput({ ref }) { return <input ref={ref} /> }.
This is a preview of SKILL.md. Download or install the skill to get the whole thing.
In the file
SKILL.md1,261 words
Files44
LicenceApache-2.0
Why you can read it

Nothing in a skill executes. The client loads the text and the model follows it, so a skill can be audited the way a runbook is — by reading it.

What it costs in context

Skills are not billed by the call. They are paid for in context: every token the instructions occupy is a token your code, your diff and your conversation cannot use. Here is what this one takes and when it takes it.

≈220
always loaded
The name and description, so the model knows the skill exists and when to reach for it.
36,730
on trigger
The instruction body and 43 supporting files, read only when the skill fires.
18.5%
of a 200k window
Ten skills this size would not fit in the window together.
050k100k150k200k context window

37k tokens, estimated from the bundle at four bytes to the token, held for the rest of the session once it triggers. Heavy. Teams tend to install this one per project rather than globally, and load it only when the job comes up.

Servers bill, skills cost

A server charges by the month. A skill charges once per session, in context, and then keeps charging it for as long as the session lives.

Before and after

The same question, put to the same model twice: once as it comes, and once with these instructions loaded.

No worked example has been published for this skill yet.

The procedure it runs

The procedure has not been set out here step by step. It is in the body of its SKILL.md: the start of it is shown above, and the whole file comes with the install.

Prose, not code

These steps are written for a model to follow, not executed by a runtime. It can still be told to skip one, and it will say so when it does.

Servers it uses

None. This skill calls no MCP servers at all.

Everything it needs is in the instructions, so it works in a project with nothing connected — the model reads the file and changes how it works with what it can already reach.

Its SKILL.md does not declare which tools it asks the agent for, so what it touches is whatever the instructions themselves ask for — read them before you install it.

What it asks for
Writes filesnot declared
Network accessnot declared

This SKILL.md carries no allowed-tools line, so neither is declared. A skill grants no permissions of its own — it can only ask for tools your client already has.

What it will not do

Every skill is narrow, and the useful ones say where they stop. These are the jobs this one is the wrong tool for.

What this skill is not for has not been published here. Nothing is implied by that: it is a section the author has not filled in.

What is in the bundle

44 files, 154.0 kB on disk. Mostly text — the instructions the model reads — with 3 scripts in it that your client would run only if the instructions tell it to.

  • SKILL.md11.6 kB
  • AGENTS.md10.3 kB
  • CHANGELOG.md7.4 kB
  • README.md6.4 kB
  • assets/output-report-template.md9.9 kB
  • evals/assertions.md3.0 kB
  • evals/evals.json12.5 kB
  • references/activity-component-show-hide.md0.8 kB
  • references/animate-svg-wrapper.md1.3 kB
  • references/avoid-usememo-simple-expressions.md1.3 kB
  • references/cache-repeated-function-calls.md2.1 kB
  • references/calculate-derived-state.md1.4 kB
  • references/compound-patterns.md22.1 kB
  • references/css-content-visibility.md1.0 kB
  • references/defer-state-reads.md1.1 kB
  • references/effect-event-deps.md2.0 kB
  • references/extract-default-parameter-value.md1.3 kB
  • references/extract-memoized-components.md1.2 kB
  • references/functional-setstate-updates.md2.2 kB
  • references/hoist-regexp-creation.md1.2 kB
  • references/hoist-static-jsx.md1.0 kB
  • references/initialize-app-once.md1.2 kB
  • references/interaction-logic-in-event-handlers.md1.4 kB
  • references/lazy-state-initialization.md2.2 kB
  • references/named-imports.md0.7 kB
  • references/narrow-effect-dependencies.md1.1 kB
  • references/no-forwardref.md0.7 kB
  • references/no-inline-components.md1.9 kB
  • references/optimize-svg-precision.md0.8 kB
  • references/prevent-hydration-mismatch.md2.8 kB
  • references/quick-checklists.md9.5 kB
  • references/react-compiler-guide.md6.5 kB
  • references/split-combined-hooks.md1.7 kB
  • references/store-event-handlers-refs.md1.3 kB
  • references/subscribe-derived-state.md1.0 kB
  • references/transitions-non-urgent-updates.md1.2 kB
  • references/use-deferred-value.md1.6 kB
  • references/use-usetransition-over-manual-loading.md2.2 kB
  • references/uselatest-stable-callbacks.md2.4 kB
  • references/useref-for-transient-values.md1.9 kB
  • scripts/README.md4.6 kB
  • scripts/check-imports.sh1.6 kB
  • scripts/detect-static-jsx.sh2.9 kB
  • scripts/find-forwardref.sh1.7 kB
What is not in it

A skill installs nothing and depends on nothing: it is a folder your client reads. This one carries 3 scripts beside the text, so the bundle is 44 files you can review in full before installing. The Apache-2.0 licence covers the templates and examples as well as the instructions.

Install

Installing copies the bundle into your project. Nothing runs at install time — the files sit on disk until the model reads them.

# React Best Practices · 37k tokens when loaded · macOS, Linux mkdir -p .claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/davidanthonyn-react-best-practices/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/react-best-practices" ] && { [ ! -e .claude/skills/react-best-practices ] || { mv .claude/skills/react-best-practices "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/react-best-practices" .claude/skills/ && echo "Installed .claude/skills/react-best-practices"
On Windows, or any OS with Node 20+
npx mcprush@latest skill add davidanthonyn/react-best-practices

Windows PowerShell says 'running scripts is disabled on this system'? Run Set-ExecutionPolicy -Scope CurrentUser RemoteSigned once, or type npx.cmd instead of npx (codex.cmd, gemini.cmd, grok.cmd likewise). PowerShell 7 needs neither. Writes to .claude/skills/react-best-practices/ in the current project. For every project instead, run mkdir -p ~/.claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/davidanthonyn-react-best-practices/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/react-best-practices" ] && { [ ! -e ~/.claude/skills/react-best-practices ] || { mv ~/.claude/skills/react-best-practices "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/react-best-practices" ~/.claude/skills/ && echo "Installed ~/.claude/skills/react-best-practices" (macOS, Linux) — or add --global to the npx line. The curl line replaces .claude/skills/react-best-practices/ only after the download succeeds, so files left there by another skill of the same name, or by an older release, do not mix in. A copy already there is moved aside, not deleted, and the line prints where. It appears as accelint-react-best-practices in Gemini CLI, Codex, Copilot and Grok (its own name); Claude Code lists it by the folder name, react-best-practices.

Which clients pick it up on their own

A skill is a folder of text. Most of these read a skills folder and pick it up without being told; the rest take the same folder another way — an upload in the app, a parameter on an API call — and then choose it by its description just the same.

Claude Code.claude/skills/
Claude DesktopCustomize › Skills
ChatGPTSkills › Create › Upload
Cursor.cursor/skills/
VS Code.github/skills/
Codex CLI.agents/skills/
Gemini CLI.gemini/skills/
Grok Build.grok/skills/
Microsoft CopilotSkills › Upload a skill
PerplexityComputer › Skills › Upload a skill
DeepSeek Harness.dsh/skills/
Zed.agents/skills/
Devin Desktop.devin/skills/
Windsurf (legacy).windsurf/skills/
OpenAI Agents SDKInstructions or sandbox Skills
HTTP / APIa request parameter
This release
Version1.8.0
Publishedno release date on file
PriceFree
Referencedavidanthonyn/react-best-practices

Versions

v1.8.0 is what is on the shelf; no release here carries a date. Instructions change more often than APIs do — a skill can be rewritten entirely without anything it depends on moving.

v1.8.0
  • No earlier releases have been published to the marketplace.
Pinning

The install command always fetches the release that is current the day you run it — v1.8.0 today — and cannot ask for an earlier one. The copy on your disk does not change until you run it again.

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Who wrote it

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davidanthonyn

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