vercel-react-best-practices

vercel-react-best-practices is a skill for Claude Code, Codex from bartstc/vite-ts-react-template. It costs 67 tokens per session (1,533 once invoked), scanned A, a copy of vercel-react-best-practices, MIT.

A set of Vercel Engineering guidelines for writing, reviewing, and refactoring React and Next.js code. It covers data fetching, page loading, JavaScript use, and other performance patterns.

In plain words
What is it for?
Use it when building or reviewing React components and Next.js pages, handling data fetching, reducing bundle size, or improving load times and rendering.
Why use it?
It helps find code patterns that can make a web application load slowly or do unnecessary work. The guidelines also help prioritize the most important performance changes.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/bartstc/vite-ts-react-template/vercel-react-best-practices
Any agent
npx skills add bartstc/vite-ts-react-template --skill vercel-react-best-practices
Clone the repo
git clone --depth 1 https://github.com/bartstc/vite-ts-react-template

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/bartstc/vite-ts-react-template/vercel-react-best-practices.svg)](https://agentmods.dev/skills/bartstc/vite-ts-react-template/vercel-react-best-practices)
Your own site
<a href="https://agentmods.dev/skills/bartstc/vite-ts-react-template/vercel-react-best-practices"><img src="https://agentmods.dev/badge/skills/bartstc/vite-ts-react-template/vercel-react-best-practices.svg" alt="Measured on agentmods" 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 1,533 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 78% 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 $0.00067 $0.01533
Opus 5 $0.00034 $0.00766
Sonnet 5 $0.00013 $0.00307
Haiku 4.5 $0.00007 $0.00153

Measured 4d ago against content hash e8841c6512b3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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 4d 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

78% identical to vercel-react-best-practices — 12 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.

.agents/skills/vercel-react-best-practices/SKILL.md · 139 lines

How it starts

The opening of the file, as written. The whole thing — 139 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 57 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

Read the full file on GitHub · 139 lines

Files

What ships with it

58 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. 4d ago First seen · 139 lines · 67 tokens per session scan A e8841c6512b3

Subscribe to this mod's changes

vercel-react-best-practices is a skill published in the GitHub repository bartstc/vite-ts-react-template (121 stars, last pushed 1mo ago), licensed MIT. It adds 67 tokens to every session and 1,533 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 78% identical to vercel-react-best-practices, differing in 12 lines, and is treated as a copy.

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