nextjs-developer

A development guide for Next.js applications, a React framework for building web pages and server-backed features. It covers the App Router, server components, server actions, route handlers, middleware, streaming, SEO metadata, and deployment.

In plain words
What is it for?
Use it to build routes, API handlers, middleware, loading and error pages, server-rendered features, SEO metadata, or deployment configurations in a Next.js project.
Why use it?
Next.js behavior varies by installed version and by whether a project uses the App Router or older Pages Router. This guide checks the project setup first so changes fit the existing code and deployment target.

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/ivklgn/ai-kit/nextjs-developer
Any agent
npx skills add ivklgn/ai-kit --skill nextjs-developer
Clone the repo
git clone --depth 1 https://github.com/ivklgn/ai-kit

Made for: Claude Code, Codex.

Per session 103 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,470 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 $0.00103 $0.01470
Opus 5 $0.00051 $0.00735
Sonnet 5 $0.00021 $0.00294
Haiku 4.5 $0.00010 $0.00147

Measured 2d ago against content hash b58838a6e7d4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

nextjs-developer 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 2d 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.

plugins/ai-kit/skills/nextjs-developer/SKILL.md · 148 lines

How it starts

The opening of the file, as written. The whole thing — 148 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Next.js Developer

Senior Next.js developer with expertise in the App Router, server components, and full-stack deployment with focus on performance and SEO excellence. Builds against the project's installed Next.js version — not an assumed one.

Step 0: Detect the Project Setup

Before writing any code:

  1. Read package.json — the installed next version drives which APIs exist (e.g. async params/searchParams and stable Turbopack in 15+, Partial Prerendering availability, caching defaults that changed between 14 and 15)
  2. Detect the router: app/ directory → App Router; pages/ → Pages Router; both → migration in progress, follow the direction the team is moving
  3. Note the deployment target (Vercel, Docker/self-hosted via output: 'standalone', static export) from next.config.* and CI files
  4. For version-specific API details, verify against the docs for the installed major (Context7 or nextjs.org) — caching semantics changed significantly across 13/14/15

Router rule: For new projects, use the App Router. In an existing Pages Router codebase, do not unilaterally convert — implement in the established router and flag migration as a separate decision. The guidance below assumes the App Router.

Core Workflow

  1. Architecture planning — Define app structure, routes, layouts, rendering strategy
  2. Implement routing — Create App Router structure with layouts, templates, loading/error states
  3. Data layer — Set up server components, data fetching, caching, revalidation
  4. Optimize — Images, fonts, bundles, streaming, edge runtime
  5. Deploy — Production build, environment setup, monitoring
    • Validate: run next build locally, confirm zero type errors, check NEXT_PUBLIC_* and server-only env vars are set, run Lighthouse/PageSpeed to confirm Core Web Vitals > 90

Reference Guide

Load detailed guidance based on context (written against Next.js 14+; double-check specifics against the installed version):

Topic Reference Load When
App Router references/app-router.md File-based routing, layouts, templates, route groups
Server Components references/server-components.md RSC patterns, streaming, client boundaries
Server Actions references/server-actions.md Form handling, mutations, revalidation
Data Fetching references/data-fetching.md fetch, caching, ISR, on-demand revalidation
Deployment references/deployment.md Vercel, self-hosting, Docker, optimization

Read the full file on GitHub · 148 lines

Files

What ships with it

6 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. 2d ago First seen · 148 lines · 103 tokens per session scan A b58838a6e7d4

Subscribe to this mod's changes

nextjs-developer is a skill published in the GitHub repository ivklgn/ai-kit (12 stars, last pushed 15d ago), licensed MIT. It adds 103 tokens to every session and 1,470 once invoked, about $0.0005 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.

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