vercel-react-best-practices

vercel-react-best-practices is a skill for Claude Code, Codex from OneDro1d/dark-factory. It costs 67 tokens per session (1,299 once invoked), scanned A, a copy of vercel-react-best-practices, Apache-2.0.

A set of performance guidelines for React, a user-interface library, and Next.js, a framework built around React. It covers code patterns for pages, data loading, browser updates, and JavaScript bundles.

In plain words
What is it for?
Use it when writing, reviewing, or refactoring React components and Next.js pages, especially around data fetching, bundle size, load times, rerenders, and rendering.
Why use it?
It helps find code choices that can make a web app load slowly or do unnecessary work. The guidance groups issues by their expected impact.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions AGENTS.md.

Good fit Use it when writing, reviewing, or refactoring React components and Next.js pages, especially around data fetching, bundle size, load times, rerenders, and rendering.

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Install with agentmods
npx agentmods add skills/onedro1d/dark-factory/vercel-react-best-practices
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 OneDro1d/dark-factory --skill vercel-react-best-practices
Clone the repo
git clone --depth 1 https://github.com/OneDro1d/dark-factory

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.

agentmods badge for vercel-react-best-practices

README.md
[![agentmods](https://agentmods.dev/badge/skills/onedro1d/dark-factory/vercel-react-best-practices/github.svg)](https://agentmods.dev/skills/onedro1d/dark-factory/vercel-react-best-practices)
Your own site
<a href="https://agentmods.dev/skills/onedro1d/dark-factory/vercel-react-best-practices"><img src="https://agentmods.dev/badge/skills/onedro1d/dark-factory/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.

agentmods 80×15 button for vercel-react-best-practices

Your own site · 80×15
<a href="https://agentmods.dev/skills/onedro1d/dark-factory/vercel-react-best-practices"><img src="https://agentmods.dev/badge/skills/onedro1d/dark-factory/vercel-react-best-practices.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 67 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,299 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 81% copy Near-identical to another mod 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00067 $0.01299
Opus 5 $0.00034 $0.00649
Sonnet 5 $0.00013 $0.00260
Haiku 4.5 $0.00007 $0.00130

Measured 8d ago against content hash 81bad0edc74b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

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 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.

Origin

This is a copy

81% identical to vercel-react-best-practices — 47 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.

skills/vercel-react-best-practices/SKILL.md · 126 lines

How it starts

The opening of the file, as written. The whole thing — 126 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 45 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 used
  • async-parallel - Use Promise.all() for independent operations
  • async-dependencies - Use better-all for partial dependencies
  • async-api-routes - Start promises early, await late in API routes
  • async-suspense-boundaries - Use Suspense to stream content

2. Bundle Size Optimization (CRITICAL)

  • bundle-barrel-imports - Import directly, avoid barrel files
  • bundle-dynamic-imports - Use next/dynamic for heavy components
  • bundle-defer-third-party - Load analytics/logging after hydration
  • bundle-conditional - Load modules only when feature is activated
  • bundle-preload - Preload on hover/focus for perceived speed

3. Server-Side Performance (HIGH)

  • server-cache-react - Use React.cache() for per-request deduplication
  • server-cache-lru - Use LRU cache for cross-request caching
  • server-serialization - Minimize data passed to client components
  • server-parallel-fetching - Restructure components to parallelize fetches
  • server-after-nonblocking - Use after() for non-blocking operations

Read the full file on GitHub · 126 lines

Files

What ships with it

48 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.

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.

  1. 8d ago First seen · 126 lines · 67 tokens per session scan A 81bad0edc74b

Subscribe to this mod's changes

vercel-react-best-practices is a skill published in the GitHub repository OneDro1d/dark-factory (0 stars, last pushed today), licensed Apache-2.0. It adds 67 tokens to every session and 1,299 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 81% identical to vercel-react-best-practices, differing in 47 lines, and is treated as a copy.

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