Borrowing it
Nothing to install: this file belongs to mercato-supply-chain/mercato-dapp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/mercato-supply-chain/mercato-dapp/develop/.agents/skills/vercel-react-best-practices/SKILL.mdgit clone --depth 1 https://github.com/mercato-supply-chain/mercato-dappWrote 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/mercato-supply-chain/mercato-dapp/vercel-react-best-practices)<a href="https://agentmods.dev/skills/mercato-supply-chain/mercato-dapp/vercel-react-best-practices"><img src="https://agentmods.dev/badge/skills/mercato-supply-chain/mercato-dapp/vercel-react-best-practices/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/mercato-supply-chain/mercato-dapp/vercel-react-best-practices"><img src="https://agentmods.dev/badge/skills/mercato-supply-chain/mercato-dapp/vercel-react-best-practices.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 | $0.00067 | $0.01594 |
| Opus 5 | $0.00034 | $0.00797 |
| Sonnet 5 | $0.00013 | $0.00319 |
| Haiku 4.5 | $0.00007 | $0.00159 |
Grade A, and why
vercel-react-best-practices 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 11d 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.
This is a copy
84% identical to vercel-react-best-practices — 29 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 142 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Vercel React Best Practices
Comprehensive performance optimization guide for React and Next.js applications, maintained by Vercel. Contains 62 rules across 8 categories, prioritized by impact to guide automated refactoring and code generation.
When to Apply
Reference these guidelines when:
- Writing new React components or Next.js pages
- Implementing data fetching (client or server-side)
- Reviewing code for performance issues
- Refactoring existing React/Next.js code
- Optimizing bundle size or load times
Rule Categories by Priority
| Priority | Category | Impact | Prefix |
|---|---|---|---|
| 1 | Eliminating Waterfalls | CRITICAL | async- |
| 2 | Bundle Size Optimization | CRITICAL | bundle- |
| 3 | Server-Side Performance | HIGH | server- |
| 4 | Client-Side Data Fetching | MEDIUM-HIGH | client- |
| 5 | Re-render Optimization | MEDIUM | rerender- |
| 6 | Rendering Performance | MEDIUM | rendering- |
| 7 | JavaScript Performance | LOW-MEDIUM | js- |
| 8 | Advanced Patterns | LOW | advanced- |
Quick Reference
1. Eliminating Waterfalls (CRITICAL)
async-defer-await- Move await into branches where actually usedasync-parallel- Use Promise.all() for independent operationsasync-dependencies- Use better-all for partial dependenciesasync-api-routes- Start promises early, await late in API routesasync-suspense-boundaries- Use Suspense to stream content
2. Bundle Size Optimization (CRITICAL)
bundle-barrel-imports- Import directly, avoid barrel filesbundle-dynamic-imports- Use next/dynamic for heavy componentsbundle-defer-third-party- Load analytics/logging after hydrationbundle-conditional- Load modules only when feature is activatedbundle-preload- Preload on hover/focus for perceived speed
3. Server-Side Performance (HIGH)
server-auth-actions- Authenticate server actions like API routesserver-cache-react- Use React.cache() for per-request deduplicationserver-cache-lru- Use LRU cache for cross-request cachingserver-dedup-props- Avoid duplicate serialization in RSC propsserver-hoist-static-io- Hoist static I/O (fonts, logos) to module levelserver-serialization- Minimize data passed to client componentsserver-parallel-fetching- Restructure components to parallelize fetchesserver-after-nonblocking- Use after() for non-blocking operations
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.
- AGENTS.md 89 KB
- README.md 3.3 KB
- rules/_sections.md 1.5 KB
- rules/_template.md 631 B
- 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-defer-await.md 2.0 KB
- rules/async-dependencies.md 1.3 KB
- rules/async-parallel.md 654 B
- rules/async-suspense-boundaries.md 2.5 KB
- rules/bundle-barrel-imports.md 2.3 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-set-map-lookups.md 532 B
- rules/js-tosorted-immutable.md 1.7 KB
- 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-transitions.md 1.0 KB
- rules/rerender-use-ref-transient-values.md 1.7 KB
- rules/server-after-nonblocking.md 2.0 KB
- rules/server-auth-actions.md 2.6 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.
- 11d ago First seen · 142 lines · 67 tokens per session scan A 0ae7b4706da6
vercel-react-best-practices is a skill published in the GitHub repository mercato-supply-chain/mercato-dapp (3 stars, last pushed 5d ago), licensed Apache-2.0. It adds 67 tokens to every session and 1,594 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 84% identical to vercel-react-best-practices, differing in 29 lines, and is treated as a copy.
Other skills, from other repositories
react-patterns
React 18/19 patterns including hooks discipline, server/client component boundaries, Suspense + error boundaries, form actions, data fetching, state management decision trees, and accessibility-first composition. Use when writing or reviewing React components.
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.
fuzzy-ranking
Rank fuzzy matches with rankItem, filter with RankingInfo.passed, compare saved ranking metadata with compareItems, and configure rankings, thresholds, accessors, min/max bounds, or diacritics. Load for @tanstack/match-sorter-utils itself or fuzzy Table filterMeta wiring.
api-not-found
Diagnose missing TanStack Table v9 exports, options, state slices, and instance methods. Load before inventing an API when code sees a type error, undefined feature method, absent object key, adapter mismatch, or v8-shaped example.
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.