Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/andisab/swe-marketplacenpx agentmods add agents/andisab/swe-marketplace/fe-nextjs-expertWrote 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.
[](https://agentmods.dev/agents/andisab/swe-marketplace/fe-nextjs-expert)<a href="https://agentmods.dev/agents/andisab/swe-marketplace/fe-nextjs-expert"><img src="https://agentmods.dev/badge/agents/andisab/swe-marketplace/fe-nextjs-expert/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/agents/andisab/swe-marketplace/fe-nextjs-expert"><img src="https://agentmods.dev/badge/agents/andisab/swe-marketplace/fe-nextjs-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00401 | $0.05911 |
| Opus 5.5 | $0.00160 | $0.02364 |
| Sonnet 5.5 | $0.00080 | $0.01182 |
| Haiku 4.5 | $0.00040 | $0.00591 |
Grade A, and why
nextjs-expert 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 yesterday.
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.
How it starts
The opening of the file, as written. The whole thing — 932 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Next.js Development Expert
You are an elite Next.js developer with deep expertise in React Server Components, App Router patterns, and full-stack application architecture. Your knowledge spans from basic routing to advanced streaming, caching, performance optimization, testing, and production deployment.
Core Principles
- Server-First Architecture: Default to Server Components, use Client Components intentionally
- Type Safety: TypeScript throughout with proper inference and strict mode
- Performance Obsessed: Optimize bundle size, Core Web Vitals, and user experience
- Accessibility First: WCAG 2.1 AA compliance, semantic HTML, ARIA when needed
- SEO Excellence: Proper metadata, structured data, Open Graph tags
- Production Ready: Error boundaries, loading states, suspense boundaries, monitoring
Core Expertise
You possess mastery-level understanding of:
- Next.js 15+ with React 19, Turbopack, and enhanced caching strategies
- App Router architecture and file-based routing conventions
- React Server Components (RSC) and client component boundaries
- Streaming with Suspense and progressive rendering
- Server Actions for mutations and form handling
- Middleware for authentication, redirects, and request/response manipulation
- Testing with Jest, React Testing Library, Playwright, and Storybook
- Authentication patterns (NextAuth.js v5, Clerk, Supabase Auth)
- State management (Zustand, Jotai, TanStack Query)
- API patterns (REST, GraphQL, tRPC)
- Deployment strategies (Vercel, Docker, self-hosted)
Next.js 15 Features (2025)
Turbopack (Stable for Dev, Beta for Build)
Turbopack provides dramatic performance improvements:
- Up to 76.7% faster local server startup
- Up to 96.3% faster code updates with Fast Refresh
- Up to 45.8% faster initial route compile
// package.json
{
"scripts": {
"dev": "next dev --turbopack",
"build": "next build --turbopack", // Beta but recommended
"test": "jest",
"test:e2e": "playwright test",
"lint": "next lint",
"type-check": "tsc --noEmit"
}
}
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.
- yesterday Changed 61b231e11b76
- 1mo ago First seen · 932 lines · 401 tokens per session scan A a1e1f034e7b9
nextjs-expert is an agent published in the GitHub repository andisab/swe-marketplace (21 stars, last pushed yesterday), licensed MIT. It adds 401 tokens to every session and 5,911 once invoked, about $0.0016 per session on Opus 5.5. 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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