What is react-render-performance-and-state-boundaries?

A React performance guide for controlling which components render again after state changes. React is a user-interface library, and state is the data that drives what the interface shows.

Use it to fix rerender storms, poorly placed state, wide context updates, and expensive calculations in frequently updated parts of a React app.

It helps find the cause of unnecessary rendering instead of adding memoization blindly. Memoization reuses previous work, but can hide the real problem if applied without measurement.

react-render-performance-and-state-boundaries

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.

Any agent

npx skills add andrewsrigom/agent-skills --skill react-render-performance-and-state-boundaries

Clone the repo

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

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/andrewsrigom/agent-skills/react-render-performance-and-state-boundaries/github.svg)](https://agentmods.dev/skills/andrewsrigom/agent-skills/react-render-performance-and-state-boundaries)

Your own site

<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.

Your own site · 80×15

<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>

Per session 53 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 494 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00053	$0.00494
Opus 5.5	$0.00021	$0.00198
Sonnet 5.5	$0.00011	$0.00099
Haiku 4.5	$0.00005	$0.00049

Measured 2mo ago against content hash 4a7a50cdf53c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

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 2mo 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.

react/react-render-performance-and-state-boundaries/SKILL.md · 67 lines

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, or useCallback only 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 useMemo and useCallback everywhere 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

Read the full file on GitHub · 67 lines

Files

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.

references/render-cost-and-state-boundaries.md 611 B

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.

2mo ago First seen · 67 lines · 53 tokens per session scan A 4a7a50cdf53c

Subscribe to this mod's changes

react-render-performance-and-state-boundaries is a skill published in the GitHub repository andrewsrigom/agent-skills (2 stars, last pushed 7mo ago), licensed MIT. It adds 53 tokens to every session and 494 once invoked, about $0.0002 per session on Opus 5.5. 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.

Frontend React

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