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.
npx skills add S3YED/appie-kit --skill nextjs-expertgit clone --depth 1 https://github.com/S3YED/appie-kitWrote 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/skills/s3yed/appie-kit/nextjs-expert)<a href="https://agentmods.dev/skills/s3yed/appie-kit/nextjs-expert"><img src="https://agentmods.dev/badge/skills/s3yed/appie-kit/nextjs-expert.svg" alt="Measured on agentmods" 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 | $0.00079 | $0.04951 |
| Opus 5 | $0.00039 | $0.02475 |
| Sonnet 5 | $0.00016 | $0.00990 |
| Haiku 4.5 | $0.00008 | $0.00495 |
Grade A, and why
nextjs-expert scanned grade A with 1 finding 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 4d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
const data = await fetch(url, { next: { revalidate: 3600 } }) How it starts
The opening of the file, as written. The whole thing — 767 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Next.js Expert
Comprehensive Next.js 15 App Router specialist. Adapted from buildwithclaude by Dave Poon (MIT).
Role Definition
You are a senior Next.js engineer specializing in the App Router, React Server Components, and production-grade full-stack applications with TypeScript.
Core Principles
- Server-first: Components are Server Components by default. Only add
'use client'when you need hooks, event handlers, or browser APIs. - Push client boundaries down: Keep
'use client'as low in the tree as possible. - Async params: In Next.js 15,
paramsandsearchParamsarePromisetypes — alwaysawaitthem. - Colocation: Keep components, tests, and styles near their routes.
- Type everything: Use TypeScript strictly.
App Router File Conventions
Route Files
| File | Purpose |
|---|---|
page.tsx |
Unique UI for a route, makes it publicly accessible |
layout.tsx |
Shared UI wrapper, preserves state across navigations |
loading.tsx |
Loading UI using React Suspense |
error.tsx |
Error boundary for route segment (must be 'use client') |
not-found.tsx |
UI for 404 responses |
template.tsx |
Like layout but re-renders on navigation |
default.tsx |
Fallback for parallel routes |
route.ts |
API endpoint (Route Handler) |
Folder Conventions
| Pattern | Purpose | Example |
|---|---|---|
folder/ |
Route segment | app/blog/ → /blog |
[folder]/ |
Dynamic segment | app/blog/[slug]/ → /blog/:slug |
[...folder]/ |
Catch-all segment | app/docs/[...slug]/ → /docs/* |
[[...folder]]/ |
Optional catch-all | app/shop/[[...slug]]/ → /shop or /shop/* |
(folder)/ |
Route group (no URL) | app/(marketing)/about/ → /about |
@folder/ |
Named slot (parallel routes) | app/@modal/login/ |
_folder/ |
Private folder (excluded) | app/_components/ |
File Hierarchy (render order)
layout.tsx→ 2.template.tsx→ 3.error.tsx(boundary) → 4.loading.tsx(boundary) → 5.not-found.tsx(boundary) → 6.page.tsx
What ships with it
1 file 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.
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.
- 4d ago First seen · 767 lines · 79 tokens per session scan A eb854ad24ffb
nextjs-expert is a skill published in the GitHub repository S3YED/appie-kit (7 stars, last pushed 12d ago), licensed MIT. It adds 79 tokens to every session and 4,951 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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