vercel-react-best-practices

vercel-react-best-practices is a skill for Claude Code, Codex from mediago-dev/mediago. It costs 67 tokens per session (1,726 once invoked), scanned A, original, MIT.

A reference guide for improving the speed of React user interfaces and Next.js websites. React is a JavaScript library for building interfaces, while Next.js is a framework built around React.

In plain words
What is it for?
Use it when writing, reviewing, or refactoring React components and Next.js pages, especially for data fetching, load times, bundle size, and rendering.
Why use it?
It helps identify slow data loading, oversized browser bundles, unnecessary updates, and inefficient server or browser work.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents); mentions AGENTS.md.

About the project

MediaGo is a cross-platform application for finding and downloading online video streams, including m3u8/HLS media and videos from services such as YouTube and Bilibili. It is for people and automated tools that need to save videos through a desktop app, Docker, browser extension, or HTTP API. The catalogue entries let coding agents operate MediaGo to create downloads and check their progress.

mediago-dev/mediago · 9,209 stars · on GitHub · downloader.caorushizi.cn

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/mediago-dev/mediago/vercel-react-best-practices
Any agent
npx skills add mediago-dev/mediago --skill vercel-react-best-practices
Clone the repo
git clone --depth 1 https://github.com/mediago-dev/mediago

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/mediago-dev/mediago/vercel-react-best-practices.svg)](https://agentmods.dev/skills/mediago-dev/mediago/vercel-react-best-practices)
Your own site
<a href="https://agentmods.dev/skills/mediago-dev/mediago/vercel-react-best-practices"><img src="https://agentmods.dev/badge/skills/mediago-dev/mediago/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 1,726 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00067 $0.01726
Opus 5 $0.00034 $0.00863
Sonnet 5 $0.00013 $0.00345
Haiku 4.5 $0.00007 $0.00173

Measured 6d ago against content hash ad2e0b0ef2bb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, 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 6d 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

Copies of this mod

8 near-identical copies found in the catalogue:

.agents/skills/vercel-react-best-practices/SKILL.md · 149 lines

How it starts

The opening of the file, as written. The whole thing — 149 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 67 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-cheap-condition-before-await - Check cheap sync conditions before awaiting flags or remote values
  • 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 · 149 lines

Files

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.

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. 6d ago First seen · 149 lines · 67 tokens per session scan A ad2e0b0ef2bb

Subscribe to this mod's changes

vercel-react-best-practices is a skill published in the GitHub repository mediago-dev/mediago (9,209 stars, last pushed 2d ago), licensed MIT. It adds 67 tokens to every session and 1,726 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.

Related

Other skills, from other repositories

remocn

Build Remotion videos with remocn — copy-paste animation components and timeline-driven UI primitives from a shadcn registry. Use when composing a video or scene in a Remotion project, adding a single animation, transition, background, or UI-block sim, or reaching for a video-ready UI primitive (button, dialog…

Remocn/remocn · 88 tokens

add-effect

Add a new effect to @remotion/effects, including implementation, package exports, docs, demos, preview images, Remotion skill updates, tests, formatting, and builds.

remotion-dev/remotion · 39 tokens

writing-tests

Rules for writing and reviewing tests in the Remotion repository. Use whenever adding, editing, or reviewing tests, especially for Studio UI, rendering, CLI, server, media, and cross-package changes, to prefer complete integration workflows over narrow helper tests and implementation details.

remotion-dev/remotion · 56 tokens

gh-stack

Manages stacked PRs and splits multi-part work into reviewable branches with gh-stack. Use for stack creation, viewing, edits, push, submit, sync, rebase, merge, or checkout; when asked to split or isolate work for review; whenever a user mentions a stack, branch layers, dependent PRs, or gh stack; or when a stack is…

remotion-dev/remotion · 80 tokens

remotion-markup

Content, animation and effects best practices.

remotion-dev/remotion · 12 tokens

writing-docs

Guides for writing and editing Remotion documentation. Use when adding docs pages, editing MDX files in packages/docs, or writing documentation content.

remotion-dev/remotion · 33 tokens