Next.js Best Practices Agent Skill

Name: Next.js Best Practices
Author: Gald3r-Labs

Next.js App Router expert guidance. Use when building, debugging, or architecting Next.js applications — routing, Server Components…

Install this skill Read the source first Free Written by Gald3r-Labs

Context cost: 4.5k tokensestimated from the bundle, loaded when it triggers
Bundle: 1 file · 18.0 kBtext throughout, nothing executable
Licence: Apache-2.0the author’s own terms
Last change: —no release on file
Servers it uses: Noneruns standalone

What it does

Next.js App Router expert guidance. Use when building, debugging, or architecting Next.js applications — routing, Server Components, Server Actions, Cache Components, layouts, middleware/proxy, data fetching, rendering strategies, and deployment on Vercel.

What this skill changes about the agent has not been set out here as a list. Its SKILL.md, shown below, says it in the author’s own words.

clouddebuggingnextjs

Filed under

Cloud & DevOps

The skill itself

A skill is instructions the model reads, so you can see what you are getting: below is the start of its SKILL.md. The front matter loads with every session, the body loads when the skill triggers, and the whole file comes with the install.

SKILL.md18.0 kB · preview

--- name: nextjs metadata: priority: 5 docs: - "https://nextjs.org/docs" - "https://nextjs.org/docs/app" sitemap: "https://nextjs.org/sitemap.xml" pathPatterns: - 'next.config.*' - 'next-env.d.ts' - 'app/**' - 'pages/**' - 'src/app/**' - 'src/pages/**' - 'tailwind.config.*' - 'postcss.config.*' - 'tsconfig.json' - 'tsconfig.*.json' - 'apps/*/app/**' - 'apps/*/pages/**' - 'apps/*/src/app/**' - 'apps/*/src/pages/**' - 'apps/*/next.config.*' bashPatterns: - '\bnext\s+(dev|build|start|lint)\b' - '\bnext\s+experimental-analyze\b' - '\bnpx\s+create-next-app\b' - '\bbunx\s+create-next-app\b' - '\bnpm\s+run\s+(dev|build|start)\b' - '\bpnpm\s+(dev|build)\b' - '\bbun\s+run\s+(dev|build)\b' promptSignals: phrases: - "next.js" - "nextjs" - "app router" - "server component" - "server action" allOf: - [middleware, next] - [layout, route] anyOf: - "pages router" - "getserversideprops" - "use server" noneOf: [] minScore: 6 validate: - pattern: export.*getServerSideProps message: 'getServerSideProps is removed in App Router — use server components or route handlers' severity: error upgradeToSkill: nextjs upgradeWhy: 'Guides migration from Pages Router getServerSideProps to App Router server components with async data fetching.' - pattern: getServerSideProps message: 'getServerSideProps is a Pages Router pattern — migrate to App Router server components' severity: warn - pattern: export.*getStaticProps message: 'getStaticProps is removed in App Router — use generateStaticParams + server components instead' severity: error upgradeToSkill: nextjs upgradeWhy: 'Guides migration from Pages Router getStaticProps to App Router generateStaticParams with server components.' - pattern: getStaticProps message: 'getStaticProps is a Pages Router pattern — migrate to App Router generateStaticParams + server components' severity: warn - pattern: from\s+['"]next/router['"] message: 'next/router is Pages Router only — use next/navigation for App Router' severity: error upgradeToSkill: nextjs upgradeWhy: 'Guides migration from next/router to next/navigation with useRouter, usePathname, useSearchParams hooks.' - pattern: (useState|useEffect) message: 'React hooks require "use client" directive — add it at the top of client components' severity: warn skipIfFileContains: "^['\"]use client['\"]" - pattern: from\s+['"]next/head['"] message: 'next/head is Pages Router — use export const metadata or generateMetadata() in App Router. Run Skill(nextjs) for metadata API guidance.' severity: error upgradeToSkill: nextjs upgradeWhy: 'Guides migration from next/head to the App Router metadata API (export const metadata / generateMetadata()).' skipIfFileContains: export\s+(const\s+)?metadata|generateMetadata - pattern: export\s+(default\s+)?function\s+middleware message: 'middleware() is renamed to proxy() in Next.js 16 — rename the function and the file to proxy.ts. Run Skill(routing-middleware) for proxy.ts migration guidance.' severity: recommended upgradeToSkill: routing-middleware upgradeWhy: 'Guides migration from middleware.ts to proxy.ts with correct file placement, runtime config, and request interception patterns.' - pattern: revalidateTag$\s*['"][^'"]+['"]\s*$ message: 'Single-arg revalidateTag(tag) is deprecated in Next.js 16 — pass a cacheLife profile: revalidateTag(tag, "max")' severity: recommended upgradeToSkill: nextjs upgradeWhy: 'Guides migration from single-arg revalidateTag to the Next.js 16 two-arg API with cacheLife profiles.' - pattern: '\bcacheHandler\s*:' message: 'Singular cacheHandler is deprecated in Next.js 16 — use cacheHandlers (plural) with per-type handlers' severity: recommended upgradeToSkill: nextjs upgradeWhy: 'Guides migration from singular cacheHandler to Next.js 16 cacheHandlers (plural) with per-type handler config.' - pattern: useRef$\s*$ message: 'useRef() requires an initial value in React 19 — use useRef(null) or useRef(0)' severity: error - pattern: next\s+export message: 'next export was removed — use output: "export" in next.config.js for static export' severity: error upgradeToSkill: nextjs upgradeWhy: 'Guides migration from next export CLI command to output: "export" in next.config for static site generation.' - pattern: (?<!await )\bcookies$\s*$ message: 'cookies() is async in Next.js 16 — add await: const cookieStore = await cookies()' severity: error skipIfFileContains: "^['\"]use client['\"]" - pattern: (?<!await )\bheaders$\s*$ message: 'headers() is async in Next.js 16 — add await: const headersList = await headers()' severity: error skipIfFileContains: "^['\"]use client['\"]" - pattern: =\s*(?!await\b)params\b message: 'params is async in Next.js 16 — add await: const { slug } = await params' severity: recommended skipIfFileContains: "^['\"]use client['\"]" - pattern: =\s*(?!await\b)searchParams\b message: 'searchParams is async in Next.js 16 — add await: const { query } = await searchParams' severity: recommended skipIfFileContains: "^['\"]use client['\"]" - pattern: 'from\s+[''""](next-auth|@auth/core)[''""]|NextAuth\(|getServerSession\(' message: 'Legacy auth pattern detected. Modern Vercel apps should use Clerk, Descope, or Auth0 for managed authentication.' severity: recommended upgradeToSkill: auth upgradeWhy: 'Migrate from next-auth/manual JWT to a managed auth provider (Clerk, Descope, Auth0) for better Vercel integration.' skipIfFileContains: '@clerk/|@descope/|@auth0/' - pattern: 'NextApiRequest|NextApiResponse|export\s+default\s+function\s+handler' message: 'Pages Router API handler detected. Use App Router route handlers with named HTTP exports instead.' severity: recommended upgradeToSkill: vercel-functions upgradeWhy: 'Migrate from Pages Router API routes to App Router route handlers with Web Request/Response API.' skipIfFileContains: 'export\s+(async\s+)?function\s+(GET|POST|PUT|PATCH|DELETE)' - pattern: 'from\s+[''""](lru-cache|node-cache|memory-cache)[''""]|new\s+(LRUCache|NodeCache)\(' message: 'In-process cache detected. Serverless deployments lose process memory between invocations.' severity: recommended upgradeToSkill: runtime-cache upgradeWhy: 'Replace process-memory caches with Vercel Runtime Cache for shared, region-aware caching.' - pattern: 'from\s+[''""](express|fastify|koa|hapi)[''""]|require\s*\(\s*[''""](express|fastify|koa|hapi)[''""]' message: 'Express/Fastify/Koa/Hapi server framework detected in a Next.js project. Use Next.js route handlers or proxy.ts for request handling instead.' severity: recommended upgradeToSkill: routing-middleware upgradeWhy: 'Replace custom server frameworks with Next.js proxy.ts for request interception and route handlers for API endpoints.' skipIfFileContains: 'proxy\.ts|from\s+[''""](next/server)[''""]|@vercel/functions' - pattern: 'from\s+[''""](typeorm|sequelize|mikro-orm|objection|bookshelf|knex)[''""]|require\s*\(\s*[''""](typeorm|sequelize|mikro-orm|objection|bookshelf|knex)[''""]' message: 'Heavy ORM detected. Consider using lightweight serverless-native alternatives like Drizzle, Prisma, or direct Neon for better cold start performance.' severity: recommended upgradeToSkill: vercel-storage upgradeWhy: 'Migrate from heavy ORMs to serverless-native database clients (Drizzle + Neon, Prisma, or @neondatabase/serverless) for faster cold starts.' skipIfFileContains: 'from\s+[''""](drizzle-orm|@neondatabase|@prisma/client|prisma)[''""]' - pattern: 'fonts\.googleapis\.com|from\s+[''""](fontsource|@fontsource)[''""]|<link[^>]*fonts\.googleapis' message: 'External font loader detected. Use next/font for zero-CLS, self-hosted font loading with automatic optimization.' severity: recommended upgradeToSkill: nextjs upgradeWhy: 'Guides migration from external font loaders to next/font with Geist Sans/Mono for zero-CLS font optimization.' skipIfFileContains: 'next/font' chainTo: - pattern: 'export\s+(default\s+)?function\s+middleware' targetSkill: routing-middleware message: 'middleware() is renamed to proxy() in Next.js 16 — loading Routing Middleware guidance for proxy.ts migration.' - pattern: "from\\s+['\"]@vercel/(postgres|kv)['\"]" targetSkill: vercel-storage message: 'Sunset storage package detected — loading Vercel Storage guidance for Neon/Upstash migration.' - pattern: "from\\s+['\"]@ai-sdk/(anthropic|openai)['\"]" targetSkill: ai-gateway message: 'Direct AI provider SDK import — loading AI Gateway guidance for unified model routing with failover and cost tracking.' - pattern: 'from\s+[''""](next-auth|@auth/core)[''""]|NextAuth\(|getServerSession\(' targetSkill: auth message: 'Legacy auth pattern detected — loading managed authentication guidance (Clerk, Descope, Auth0).' - pattern: 'NextApiRequest|NextApiResponse|export\s+default\s+function\s+handler' targetSkill: vercel-functions message: 'Pages Router API handler detected — loading Vercel Functions guidance for App Router migration.' - pattern: 'from\s+[''""](lru-cache|node-cache|memory-cache)[''""]|new\s+(LRUCache|NodeCache)\(' targetSkill: runtime-cache message: 'In-process cache detected — loading Runtime Cache guidance for serverless-compatible caching.' - pattern: 'fetch\s*\(\s*[''""](https?://)?(api\.openai\.com|api\.anthropic\.com|api\.cohere\.ai)' targetSkill: ai-gateway message: 'Raw AI provider fetch URL detected — loading AI Gateway guidance for unified routing, failover, and OIDC auth.' skipIfFileContains: '@ai-sdk/|from\s+[''""](ai)[''""]|ai-gateway|gateway\(' - pattern: 'jwt\.(sign|verify|decode)\(|from\s+[''""](jsonwebtoken)[''""]|new\s+SignJWT\(|jwtVerify\(' targetSkill: auth message: 'Manual JWT token handling detected — loading Auth guidance for managed authentication (Clerk, Descope, Auth0).' skipIfFileContains: 'clerkMiddleware|@clerk/|@auth0/|@descope/|from\s+[''""](next-auth)[''""]' - pattern: 'from\s+[''"]@/components/ui/|from\s+[''"]@/components/ui[''""]' targetSkill: shadcn message: 'shadcn/ui component imports detected — loading shadcn guidance for component composition, theming, and registry patterns.' skipIfFileContains: 'shadcn|components\.json' - pattern: 'from\s+[''""](styled-components|@emotion/(react|styled)|@mui/material)[''""]' targetSkill: shadcn message: 'CSS-in-JS library detected — loading shadcn/ui guidance for Tailwind CSS + Radix UI component patterns (Vercel recommended).' skipIfFileContains: '@/components/ui|shadcn' - pattern: 'getInitialProps' targetSkill: nextjs message: 'getInitialProps is a legacy Pages Router pattern — loading Next.js guidance for App Router migration with server components and async data fetching.' skipIfFileContains: 'app/.*page\.|generateStaticParams|use cache' - pattern: 'export.*getServerSideProps|getServerSideProps\s*\(' targetSkill: nextjs message: 'getServerSideProps is a Pages Router pattern — loading Next.js guidance for App Router migration with server components and async data fetching.' skipIfFileContains: 'generateStaticParams|use cache|app/.*page\.' - pattern: 'export.*getStaticProps|getStaticProps\s*\(' targetSkill: nextjs message: 'getStaticProps is a Pages Router pattern — loading Next.js guidance for App Router migration with generateStaticParams and server components.' skipIfFileContains: 'generateStaticParams|use cache|app/.*page\.' - pattern: '_app\.(tsx?|jsx?)' targetSkill: nextjs message: '_app.tsx is a Pages Router pattern — loading Next.js guidance for App Router layout.tsx migration.' skipIfFileContains: 'app/layout\.|app/.*layout\.' - pattern: '_document\.(tsx?|jsx?)' targetSkill: nextjs message: '_document.tsx is a Pages Router pattern — loading Next.js guidance for App Router layout.tsx with metadata API migration.' skipIfFileContains: 'app/layout\.|app/.*layout\.' - pattern: "from\\s+['\"]next/document['\"]" targetSkill: nextjs message: 'next/document is Pages Router only — loading Next.js guidance for App Router layout.tsx with html/body structure.' skipIfFileContains: 'app/layout\.|app/.*layout\.' - pattern: 'pages/api/' targetSkill: vercel-functions message: 'Pages Router API route (pages/api/) detected — loading Vercel Functions guidance for App Router route handlers with named HTTP exports.' skipIfFileContains: 'export\s+(async\s+)?function\s+(GET|POST|PUT|PATCH|DELETE)' retrieval: aliases: - next.js - nextjs app - react framework - app router intents: - set up routing and layouts in a Next.js app - choose between server and client components for a feature - configure data fetching or caching in App Router - add middleware or proxy logic to handle requests - set up server rendering for React pages - add a new page with dynamic route segments entities: - App Router - Server Components - Server Actions - generateMetadata - layout - proxy - next.config examples: - add a new page with dynamic routing - should this be a server or client component - set up middleware for auth redirects - configure caching for this data fetch - set up server rendering for my pages ---

288# Next.js Best Practices

289

290Apply these rules when writing or reviewing Next.js code.

291

292## File Conventions

293

294See [file-conventions.md](./file-conventions.md) for:

295- Project structure and special files

296- Route segments (dynamic, catch-all, groups)

297- Parallel and intercepting routes

298- Middleware rename in v16 (middleware → proxy)

299

300## RSC Boundaries

301

302Detect invalid React Server Component patterns.

303

304See [rsc-boundaries.md](./rsc-boundaries.md) for:

305- Async client component detection (invalid)

306- Non-serializable props detection

This is a preview of SKILL.md. Download or install the skill to get the whole thing.

In the file

SKILL.md1,862 words

Files1

LicenceApache-2.0

Why you can read it

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≈3,540

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960

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SKILL.md18.0 kB

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Installing copies the bundle into your project. Nothing runs at install time — the files sit on disk until the model reads them.

# Next.js Best Practices · 4.5k tokens when loaded · macOS, Linux
mkdir -p .claude/skills && t=$(mktemp -d) &&
  curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/gald3r-labs-next-js-best-practices/bundle.tar.gz &&
  tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/next-js-best-practices" ] &&
  { [ ! -e .claude/skills/next-js-best-practices ] || { mv .claude/skills/next-js-best-practices "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } &&
  mv "$t/next-js-best-practices" .claude/skills/ && echo "Installed .claude/skills/next-js-best-practices"

On Windows, or any OS with Node 20+

npx mcprush@latest skill add gald3r-labs/next-js-best-practices

Windows PowerShell says 'running scripts is disabled on this system'? Run Set-ExecutionPolicy -Scope CurrentUser RemoteSigned once, or type npx.cmd instead of npx (codex.cmd, gemini.cmd, grok.cmd likewise). PowerShell 7 needs neither. Writes to .claude/skills/next-js-best-practices/ in the current project. For every project instead, run mkdir -p ~/.claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/gald3r-labs-next-js-best-practices/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/next-js-best-practices" ] && { [ ! -e ~/.claude/skills/next-js-best-practices ] || { mv ~/.claude/skills/next-js-best-practices "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/next-js-best-practices" ~/.claude/skills/ && echo "Installed ~/.claude/skills/next-js-best-practices" (macOS, Linux) — or add --global to the npx line. The curl line replaces .claude/skills/next-js-best-practices/ only after the download succeeds, so files left there by another skill of the same name, or by an older release, do not mix in. A copy already there is moved aside, not deleted, and the line prints where. It appears as nextjs in Gemini CLI, Codex, Copilot and Grok (its own name); Claude Code lists it by the folder name, next-js-best-practices.

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Referencegald3r-labs/next-js-best-practices

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