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 skills add andrewsrigom/agent-skills --skill react-render-performance-and-state-boundariesgit clone --depth 1 https://github.com/andrewsrigom/agent-skillsWrote 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/skills/andrewsrigom/agent-skills/react-render-performance-and-state-boundaries)<a href="https://agentmods.dev/skills/andrewsrigom/agent-skills/react-render-performance-and-state-boundaries"><img src="https://agentmods.dev/badge/skills/andrewsrigom/agent-skills/react-render-performance-and-state-boundaries/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/andrewsrigom/agent-skills/react-render-performance-and-state-boundaries"><img src="https://agentmods.dev/badge/skills/andrewsrigom/agent-skills/react-render-performance-and-state-boundaries.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00053 | $0.00494 |
| Opus 5 | $0.00026 | $0.00247 |
| Sonnet 5 | $0.00011 | $0.00099 |
| Haiku 4.5 | $0.00005 | $0.00049 |
Grade A, and why
react-render-performance-and-state-boundaries 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 8d 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.
How it starts
The opening of the file, as written. The whole thing — 67 lines — stays where its author put it; the contents beside it link to each section on GitHub.
React Render Performance And State Boundaries
Use this skill when the main problem is React doing too much work after state changes.
Scope
- rerender storms
- bad state placement
- context update blast radius
- expensive derived values in hot paths
- choosing between boundary changes and memoization
Default path
- Find the state change that triggers the slow path.
- Move state ownership as close as possible to the components that truly need it.
- Reduce rerender blast radius before adding memoization.
- Split hot and cold subtrees when one interaction keeps invalidating both.
- Add
memo,useMemo, oruseCallbackonly when measurement shows they remove meaningful work.
When to deviate
- Keep shared state higher only when multiple distant consumers truly need synchronized ownership.
- Use memoization earlier when a stable expensive child is already isolated and the props are naturally memo-friendly.
- Reach for virtualization when list size, not state placement, is the dominant cost.
Guardrails
- State placement is usually a bigger win than sprinkling memoization.
- Context is for shared semantics, not every frequently changing local concern.
- Derived values should usually stay derived, not become mirrored state.
- Avoid making code harder to reason about for theoretical render wins.
Avoid
- adding
useMemoanduseCallbackeverywhere by default - storing derived values in state just to avoid recalculation
- putting frequently changing state high in the tree without a hard reason
- using one global context for data that changes at very different rates
Verification checklist
- the triggering state change is identified
- the new state owner is deliberate
- rerender scope is smaller after the change
- memoization is justified by measured work, not habit
- the code is still easier to reason about than before
Output Shape
When answering with this skill, prefer:
- trigger causing extra work
- current state owner
- better boundary
- whether memoization is warranted
- verification approach
What ships with it
1 file 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.
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.
- 8d ago First seen · 67 lines · 53 tokens per session scan A 4a7a50cdf53c
react-render-performance-and-state-boundaries is a skill published in the GitHub repository andrewsrigom/agent-skills (2 stars, last pushed 5mo ago), licensed MIT. It adds 53 tokens to every session and 494 once invoked, about $0.0003 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 2026-08-31.
Other skills, from other repositories
chakra-ui-builder
Build responsive, accessible UI components and layouts using Chakra UI v3, install or configure Chakra UI in new and existing projects, and design scalable themes using tokens, semantic tokens, recipes, and slot recipes. Use this skill whenever a user asks to build, create, or generate any UI component, page, form…
material-ui-tailwind
Integrates Material UI with Tailwind CSS v4 using cascade layers (enableCssLayer, @layer order) and documents Tailwind v3 interoperability (preflight, important, injectFirst, portals). Use when combining MUI with Tailwind utilities, slotProps className, or theme token bridges.
r3f-best-practices
React Three Fiber (R3F) and Poimandres ecosystem best practices. Use when writing, reviewing, or optimizing R3F code. Triggers on tasks involving @react-three/fiber, @react-three/drei, zustand, @react-three/postprocessing, @react-three/rapier, or leva.
create-site
Creates a new Power Pages code site (SPA) using React, Angular, Vue, or Astro. Guides through the full process from initial concept to deployed site: requirements discovery, scaffolding, component planning, design, implementation, validation, and deployment. Use when the user wants to create, build, or scaffold a new…
fast-typescript-check
Keep www-sacred's TypeScript fast to type-check and fast to run. Use when touching the ASCII/canvas animation components (the only real per-frame code here), tightening type-check wall-clock, or auditing a change for runtime or compiler regressions. Scoped to this repo — a React 19 / Next.js 16 component library plus…
menu-testing-ssr
Server rendering and testing for react-horizontal-scrolling-menu: the library is client-only ('use client' required in React Server Components, else "createContext is not a function"), SSR first paint is controlled by the useIsVisible defaultValue argument (canonical ('first', true) / ('last', false))…