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 LeahyCC/claude-skills --skill nextjs-app-routergit clone --depth 1 https://github.com/LeahyCC/claude-skillsWrote 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/leahycc/claude-skills/nextjs-app-router)<a href="https://agentmods.dev/skills/leahycc/claude-skills/nextjs-app-router"><img src="https://agentmods.dev/badge/skills/leahycc/claude-skills/nextjs-app-router/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/skills/leahycc/claude-skills/nextjs-app-router"><img src="https://agentmods.dev/badge/skills/leahycc/claude-skills/nextjs-app-router.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 | $0.00069 | $0.01840 |
| Opus 5 | $0.00034 | $0.00920 |
| Sonnet 5 | $0.00014 | $0.00368 |
| Haiku 4.5 | $0.00007 | $0.00184 |
Grade A, and why
nextjs-app-router 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 11d 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.
How it starts
The opening of the file, as written. The whole thing — 181 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Next.js App Router
Production guidance for Next.js 16 App Router applications. Server-first: keep rendering, data access, and secrets on the server; add 'use client' only for interactivity.
Architecture Overview
Request → proxy.ts → Route (layout/page) → Server Components → DB/API
│ │
│ ▼
│ RSC Payload + HTML
│ │
▼ ▼
Route Handlers Streaming + Suspense
│
▼
Client Components (hydrate)
Quick Reference
| Need help with... | Resource |
|---|---|
| Server vs Client Components | server-components.md |
Data fetching, Suspense, use() |
data-fetching.md |
| Cache Components, revalidation | caching.md |
| Layouts, navigation, dynamic routes | routing.md |
proxy.ts, auth gates |
proxy.md |
error.tsx, loading.tsx, notFound() |
error-handling.md |
| Metadata, App Router ownership | metadata-and-seo.md |
next/image, next/font |
assets.md |
| Pages Router migration | migration.md |
| Next.js 15 → 16 upgrade | version-changes.md |
Decision Matrix: "What Do I Use?"
| Need | Solution | Resource |
|---|---|---|
| Read database / API | Server Component | server-components, data-fetching |
| User interaction / state | Client Component | server-components |
| Form mutation | Server Action | data-fetching |
| HTTP endpoint / webhook | Route Handler | data-fetching |
| Cache expensive data | 'use cache' + cacheLife |
caching |
| Invalidate after user edit | updateTag() |
caching |
| Invalidate from webhook | revalidateTag(tag, 'max') |
caching |
| Auth redirect before render | proxy.ts |
proxy |
| Loading UI | loading.tsx or <Suspense> |
error-handling, data-fetching |
| Uncaught error | error.tsx |
error-handling |
| Missing resource | notFound() |
error-handling |
| SEO metadata | metadata / generateMetadata |
metadata-and-seo |
| Optimize images/fonts | next/image, next/font |
assets |
What ships with it
11 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.
- README.md 3.3 KB
- resources/assets.md 14 KB
- resources/caching.md 17 KB
- resources/data-fetching.md 14 KB
- resources/error-handling.md 15 KB
- resources/metadata-and-seo.md 11 KB
- resources/migration.md 13 KB
- resources/proxy.md 14 KB
- resources/routing.md 16 KB
- resources/server-components.md 12 KB
- resources/version-changes.md 16 KB
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.
- 11d ago First seen · 181 lines · 69 tokens per session scan A 95ccdefce298
nextjs-app-router is a skill published in the GitHub repository LeahyCC/claude-skills (3 stars, last pushed 1mo ago), licensed MIT. It adds 69 tokens to every session and 1,840 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 2026-08-31.
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