.claude/skills/building-nextjs-apps/SKILL.md
Build Next.js 16 applications with correct patterns and distinctive design. Use when creating pages, layouts, dynamic routes, upgrading from Next.js 15, or implementing proxy.ts. Covers breaking changes (async params/searchParams, Turbopack, cacheComponents) and frontend aesthetics. NOT when building non-React or backend-only applications.
npx skillsauth add Asmayaseen/hackathon-2 building-nextjs-appsInstall this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.
3 of 9 scanners reported clean
Some scanners were skipped, did not run, or reported a non-clean status. Review each row below.
Build Next.js 16 applications correctly with distinctive design.
THIS IS THE MOST COMMON MISTAKE.
// WRONG - Next.js 15 pattern (WILL FAIL)
export default function Page({ params }: { params: { id: string } }) {
return <div>ID: {params.id}</div>
}
// CORRECT - Next.js 16 pattern
export default async function Page({
params,
}: {
params: Promise<{ id: string }>
}) {
const { id } = await params
return <div>ID: {id}</div>
}
"use client"
import { use } from "react"
export default function ClientPage({
params,
}: {
params: Promise<{ id: string }>
}) {
const { id } = use(params)
return <div>ID: {id}</div>
}
export default async function Page({
searchParams,
}: {
searchParams: Promise<{ page?: string }>
}) {
const { page } = await searchParams
return <div>Page: {page ?? "1"}</div>
}
npx create-next-app@latest my-app --typescript --tailwind --eslint
cd my-app
# Add shadcn/ui
npx shadcn@latest init
npx shadcn@latest add button form dialog table sidebar
// app/layout.tsx
export default function RootLayout({
children,
}: {
children: React.ReactNode
}) {
return (
<html lang="en">
<body className="min-h-screen">
{children}
</body>
</html>
)
}
// app/tasks/[id]/page.tsx
export default async function TaskPage({
params,
}: {
params: Promise<{ id: string }>
}) {
const { id } = await params
const task = await getTask(id)
return (
<main>
<h1>{task.title}</h1>
</main>
)
}
// app/actions.ts
"use server"
import { revalidatePath } from "next/cache"
export async function createTask(formData: FormData) {
const title = formData.get("title") as string
await db.insert(tasks).values({ title })
revalidatePath("/tasks")
}
// Usage in component
<form action={createTask}>
<input name="title" />
<button type="submit">Create</button>
</form>
// app/api/tasks/route.ts
import { NextResponse } from "next/server"
export async function GET() {
const tasks = await db.select().from(tasksTable)
return NextResponse.json(tasks)
}
export async function POST(request: Request) {
const body = await request.json()
const task = await db.insert(tasksTable).values(body).returning()
return NextResponse.json(task, { status: 201 })
}
// proxy.ts (replaces middleware.ts in Next.js 16)
import { NextRequest } from "next/server"
export function proxy(request: NextRequest) {
// Authentication check
const token = request.cookies.get("token")
if (!token && request.nextUrl.pathname.startsWith("/dashboard")) {
return Response.redirect(new URL("/login", request.url))
}
}
export const config = {
matcher: ["/dashboard/:path*"],
}
// This runs on the server - can use async/await directly
async function TaskList() {
const tasks = await fetch("https://api.example.com/tasks", {
cache: "no-store", // SSR, or
// next: { revalidate: 60 } // ISR
}).then(r => r.json())
return (
<ul>
{tasks.map(task => <li key={task.id}>{task.title}</li>)}
</ul>
)
}
"use client"
import useSWR from "swr"
const fetcher = (url: string) => fetch(url).then(r => r.json())
export function ClientTaskList() {
const { data, error, isLoading } = useSWR("/api/tasks", fetcher)
if (isLoading) return <div>Loading...</div>
if (error) return <div>Error loading tasks</div>
return (
<ul>
{data.map(task => <li key={task.id}>{task.title}</li>)}
</ul>
)
}
app/
├── layout.tsx # Root layout
├── page.tsx # Home page
├── globals.css # Global styles
├── api/ # API routes
│ └── tasks/route.ts
├── tasks/
│ ├── page.tsx # /tasks
│ └── [id]/page.tsx # /tasks/:id
├── actions.ts # Server actions
└── proxy.ts # Request proxy (middleware)
components/
├── ui/ # shadcn/ui components
└── task-list.tsx # App components
lib/
├── db.ts # Database connection
└── utils.ts # Utilities
Use the next-devtools-mcp server for runtime diagnostics and development automation.
claude mcp add next-devtools npx next-devtools-mcp@latest
Or in settings.json:
{
"mcpServers": {
"next-devtools": {
"type": "stdio",
"command": "npx",
"args": ["next-devtools-mcp@latest"]
}
}
}
| Tool | Purpose |
|------|---------|
| init | Establish context with available tools and best practices |
| nextjs_docs | Search and fetch official Next.js documentation |
| browser_eval | Automate browser testing with Playwright |
| nextjs_index | Discover running Next.js dev servers |
| nextjs_call | Execute MCP tools on running dev servers |
| upgrade_nextjs_16 | Automated upgrade with codemods |
| enable_cache_components | Configure Cache Components for Next.js 16 |
1. Get Real-time Errors
"What build errors are there in my Next.js app?"
"Show me TypeScript errors in the current project"
2. Debug Runtime Issues
"Check the dev server logs for errors"
"What runtime errors are happening on the dashboard page?"
3. Upgrade Assistance
"Upgrade this project to Next.js 16"
"Enable cache components for this app"
4. Documentation Lookup
"How do I use the Image component in Next.js 16?"
"What's the correct way to handle dynamic routes?"
Next.js 16+ exposes a built-in MCP endpoint at http://localhost:3000/_next/mcp (or your dev server port). The devtools MCP automatically discovers and connects to running servers.
Run: python3 scripts/verify.py
Expected: ✓ building-nextjs-apps skill ready
--library-id /vercel/next.js --topic routingdevelopment
Systematic methodology for debugging bugs, test failures, and unexpected behavior. Use when encountering any technical issue before proposing fixes. Covers root cause investigation, pattern analysis, hypothesis testing, and fix implementation. Use ESPECIALLY when under time pressure, "just one quick fix" seems obvious, or you've already tried multiple fixes. NOT for exploratory code reading.
development
Build beautiful, accessible UIs with shadcn/ui components in Next.js. Use when creating forms, dialogs, tables, sidebars, or any UI components. Covers installation, component patterns, react-hook-form + Zod validation, and dark mode setup. NOT when building non-React applications or using different component libraries.
tools
Implement real-time streaming UI patterns for AI chat applications. Use when adding response lifecycle handlers, progress indicators, client effects, or thread state synchronization. Covers onResponseStart/End, onEffect, ProgressUpdateEvent, and client tools. NOT when building basic chat without real-time feedback.
tools
Builds AI agents using OpenAI Agents SDK with async/await patterns and multi-agent orchestration. Use when creating tutoring agents, building agent handoffs, implementing tool-calling agents, or orchestrating multiple specialists. Covers Agent class, Runner patterns, function tools, guardrails, and streaming responses. NOT when using raw OpenAI API without SDK or other agent frameworks like LangChain.