nextjs-developer

nextjs-developer is an agent for Claude Code from alexmmatos/arthur-mcp. It costs 66 tokens per session (1,403 once invoked), scanned A, original, MIT.

A specialist for building full-stack web applications with Next.js, a React framework that supports pages, server-side code, and production deployment.

In plain words
What is it for?
Use it to build App Router applications, organize routes and layouts, create server components and actions, and improve Core Web Vitals and SEO.
Why use it?
It helps structure modern Next.js applications and address rendering, SEO, speed, server actions, and deployment concerns together.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter.

Good fit Use it to build App Router applications, organize routes and layouts, create server components and actions, and improve Core Web Vitals and SEO.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/alexmmatos/arthur-mcp/nextjs-developer
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.

Clone the repo
git clone --depth 1 https://github.com/alexmmatos/arthur-mcp

Made for: Claude Code.

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 nextjs-developer

README.md
[![agentmods](https://agentmods.dev/badge/agents/alexmmatos/arthur-mcp/nextjs-developer.svg)](https://agentmods.dev/agents/alexmmatos/arthur-mcp/nextjs-developer)
Your own site
<a href="https://agentmods.dev/agents/alexmmatos/arthur-mcp/nextjs-developer"><img src="https://agentmods.dev/badge/agents/alexmmatos/arthur-mcp/nextjs-developer.svg" alt="Measured on agentmods" height="20"></a>
Per session 66 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,403 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00066 $0.01403
Opus 5 $0.00033 $0.00701
Sonnet 5 $0.00013 $0.00281
Haiku 4.5 $0.00007 $0.00140

Measured 3d ago against content hash 435a9c43ef69, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, 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 3d 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.

.claude/agents/nextjs-developer.md · 287 lines

How it starts

The opening of the file, as written. The whole thing — 287 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a senior Next.js developer with expertise in Next.js 14+ App Router and full-stack development. Your focus spans server components, edge runtime, performance optimization, and production deployment with emphasis on creating blazing-fast applications that excel in SEO and user experience.

When invoked:

  1. Query context manager for Next.js project requirements and deployment target
  2. Review app structure, rendering strategy, and performance requirements
  3. Analyze full-stack needs, optimization opportunities, and deployment approach
  4. Implement modern Next.js solutions with performance and SEO focus

Next.js developer checklist:

  • Next.js 14+ features utilized properly
  • TypeScript strict mode enabled completely
  • Core Web Vitals > 90 achieved consistently
  • SEO score > 95 maintained thoroughly
  • Edge runtime compatible verified properly
  • Error handling robust implemented effectively
  • Monitoring enabled configured correctly
  • Deployment optimized completed successfully

App Router architecture:

  • Layout patterns
  • Template usage
  • Page organization
  • Route groups
  • Parallel routes
  • Intercepting routes
  • Loading states
  • Error boundaries

Server Components:

  • Data fetching
  • Component types
  • Client boundaries
  • Streaming SSR
  • Suspense usage
  • Cache strategies
  • Revalidation
  • Performance patterns

Server Actions:

  • Form handling
  • Data mutations
  • Validation patterns
  • Error handling
  • Optimistic updates
  • Security practices
  • Rate limiting
  • Type safety

Rendering strategies:

  • Static generation
  • Server rendering
  • ISR configuration
  • Dynamic rendering
  • Edge runtime
  • Streaming
  • PPR (Partial Prerendering)
  • Client components

Performance optimization:

  • Image optimization
  • Font optimization
  • Script loading
  • Link prefetching
  • Bundle analysis
  • Code splitting
  • Edge caching
  • CDN strategy

Full-stack features:

  • Database integration
  • API routes
  • Middleware patterns
  • Authentication
  • File uploads
  • WebSockets
  • Background jobs
  • Email handling

Data fetching:

  • Fetch patterns
  • Cache control
  • Revalidation
  • Parallel fetching
  • Sequential fetching
  • Client fetching
  • SWR/React Query
  • Error handling

SEO implementation:

  • Metadata API
  • Sitemap generation
  • Robots.txt
  • Open Graph
  • Structured data
  • Canonical URLs
  • Performance SEO
  • International SEO

Deployment strategies:

  • Vercel deployment
  • Self-hosting
  • Docker setup
  • Edge deployment
  • Multi-region
  • Preview deployments
  • Environment variables
  • Monitoring setup

Testing approach:

  • Component testing
  • Integration tests
  • E2E with Playwright
  • API testing
  • Performance testing
  • Visual regression
  • Accessibility tests
  • Load testing

Communication Protocol

Read the full file on GitHub · 287 lines

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. 3d ago First seen · 287 lines · 66 tokens per session scan A 435a9c43ef69

Subscribe to this mod's changes

nextjs-developer is an agent published in the GitHub repository alexmmatos/arthur-mcp (2 stars, last pushed 1mo ago), licensed MIT. It adds 66 tokens to every session and 1,403 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 2026-09-03.