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 agentmods add skills/clubpay/ronykit/react-performancenpx skills add clubpay/ronykit --skill react-performancegit clone --depth 1 https://github.com/clubpay/ronykitWhat 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 | $0.00064 | $0.02713 |
| Opus 5 | $0.00032 | $0.01357 |
| Sonnet 5 | $0.00013 | $0.00543 |
| Haiku 4.5 | $0.00006 | $0.00271 |
Grade A, and why
react-performance 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 yesterday.
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 — 215 lines — stays where its author put it; the contents beside it link to each section on GitHub.
React Performance
70 performance rules for React and Next.js, vendored from Vercel Engineering's
react-best-practices (MIT). The full rule set lives in rules/ — each file is
self-contained (impact metric + incorrect→correct code). This SKILL.md is the
index and router: it carries the highest-impact patterns inline so you can
act without opening anything, and points you to the exact rule file for depth.
For Server Components, data fetching, caching, Server Actions, and route-level
code splitting at a higher level, see nextjs-modern. The async-* and
server-* rules here are the detailed reference for that same ground.
When to use
- Writing or reviewing React components, hooks, or Next.js pages for speed.
- Chasing slow renders, janky interactions, large bundles, or poor Core Web Vitals (LCP, INP, TTFB).
- Refactoring code that re-renders too often or ships too much JS.
How to use the rules (read this first)
- Measure before optimizing. Profile the proven bottleneck with the React DevTools Profiler, the Next.js bundle analyzer, and a Lighthouse/Web Vitals pass. Don't memoize on a hunch — most "just to be safe" memoization only adds cost.
- Apply in priority order (table below) — the top categories move the needle far more than the bottom ones.
- Open the specific rule file before applying it, using the routing table
and index below. Each
rules/<name>.mdhas the exact incorrect→correct code and the impact metric. Match the example, don't paraphrase from memory.
Priority order
| # | Category | Impact | Prefix |
|---|---|---|---|
| 1 | Eliminate waterfalls | CRITICAL | async- |
| 2 | Bundle size | CRITICAL | bundle- |
| 3 | Server-side perf | HIGH | server- |
| 4 | Client data fetching | MEDIUM-HIGH | client- |
| 5 | Re-render optimization | MEDIUM | rerender- |
| 6 | Rendering performance | MEDIUM | rendering- |
| 7 | JavaScript hot paths | LOW-MEDIUM | js- |
| 8 | Advanced patterns | LOW | advanced- |
What ships with it
60 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.
- rules/_sections.md 1.5 KB
- rules/_template.md 631 B
- rules/advanced-effect-event-deps.md 1.8 KB
- rules/advanced-event-handler-refs.md 1.4 KB
- rules/advanced-init-once.md 958 B
- rules/advanced-use-latest.md 1.0 KB
- rules/async-api-routes.md 1.1 KB
- rules/async-cheap-condition-before-await.md 1.2 KB
- rules/async-defer-await.md 2.2 KB
- rules/async-dependencies.md 1.3 KB
- rules/async-parallel.md 654 B
- rules/async-suspense-boundaries.md 2.5 KB
- rules/bundle-analyzable-paths.md 2.3 KB
- rules/bundle-barrel-imports.md 2.7 KB
- rules/bundle-conditional.md 949 B
- rules/bundle-defer-third-party.md 920 B
- rules/bundle-dynamic-imports.md 791 B
- rules/bundle-preload.md 1.1 KB
- rules/client-event-listeners.md 1.9 KB
- rules/client-localstorage-schema.md 1.9 KB
- rules/client-passive-event-listeners.md 1.6 KB
- rules/client-swr-dedup.md 1.1 KB
- rules/js-batch-dom-css.md 3.2 KB
- rules/js-cache-function-results.md 1.9 KB
- rules/js-cache-property-access.md 532 B
- rules/js-cache-storage.md 1.6 KB
- rules/js-combine-iterations.md 753 B
- rules/js-early-exit.md 1.1 KB
- rules/js-flatmap-filter.md 1.4 KB
- rules/js-hoist-regexp.md 1.0 KB
- rules/js-index-maps.md 837 B
- rules/js-length-check-first.md 1.7 KB
- rules/js-min-max-loop.md 2.2 KB
- rules/js-request-idle-callback.md 2.6 KB
- rules/js-set-map-lookups.md 532 B
- rules/js-tosorted-immutable.md 1.7 KB
- rules/metadata.json 921 B
- rules/rendering-activity.md 564 B
- rules/rendering-animate-svg-wrapper.md 1.2 KB
- rules/rendering-conditional-render.md 980 B
- rules/rendering-content-visibility.md 815 B
- rules/rendering-hoist-jsx.md 1.0 KB
- rules/rendering-hydration-no-flicker.md 2.3 KB
- rules/rendering-hydration-suppress-warning.md 872 B
- rules/rendering-resource-hints.md 2.5 KB
- rules/rendering-script-defer-async.md 1.8 KB
- rules/rendering-svg-precision.md 588 B
- rules/rendering-usetransition-loading.md 2.0 KB
- rules/rerender-defer-reads.md 973 B
- rules/rerender-dependencies.md 824 B
- rules/rerender-derived-state-no-effect.md 1.2 KB
- rules/rerender-derived-state.md 728 B
- rules/rerender-functional-setstate.md 2.9 KB
- rules/rerender-lazy-state-init.md 2.0 KB
- rules/rerender-memo-with-default-value.md 1.1 KB
- rules/rerender-memo.md 1.1 KB
- rules/rerender-move-effect-to-event.md 1.2 KB
- rules/rerender-no-inline-components.md 2.1 KB
- rules/rerender-simple-expression-in-memo.md 1018 B
- rules/rerender-split-combined-hooks.md 1.8 KB
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.
- yesterday First seen · 215 lines · 64 tokens per session scan A 66494d60ef52
react-performance is a skill published in the GitHub repository clubpay/ronykit (38 stars, last pushed 3d ago), licensed BSD-3-Clause. It adds 64 tokens to every session and 2,713 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 2026-08-30.
Other skills, from other repositories
sql-database-support
Guides classifying, gap-analyzing, and scaffolding support for a new SQL database in pREST (wire-compatible variants like TimescaleDB or new dialects). Use when adding database support, creating integration/ /, DIFFERENCES.md, adapters/ , per-DB docker-compose or GitHub workflows, or planning where config/app wiring…
prest-integration-tests
Guides writing and reviewing pREST Docker/network integration tests under integration/ so each request is human-readable via step comments or table-driven descriptions. Use when adding or editing integration//test.go, HTTP controller E2E coverage, make test-integration, test-integration-postgres…
ast-introspection
Use Go AST-aware analysis to enumerate symbols, extract signatures, and propose mechanically safe refactors (read-only by default).
ci-orchestrator
Run a CI-like pipeline locally (format, lint, vet, static-analysis, tests) and summarize per-step results with remediation guidance.
config-loader-helper
Diagnose configuration-related failures, enumerate required env vars, and guide safe local test setup (no secrets).
db-infra-mocks
Propose minimal seams and local substitutes so tests run without real RDBMS/Redis/Mongo infrastructure.