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/ryanrawlingswang/llm-rulesnpx agentmods add rules/ryanrawlingswang/llm-rules/nextjs-developmentWrote 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/rules/ryanrawlingswang/llm-rules/nextjs-development)<a href="https://agentmods.dev/rules/ryanrawlingswang/llm-rules/nextjs-development"><img src="https://agentmods.dev/badge/rules/ryanrawlingswang/llm-rules/nextjs-development/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/rules/ryanrawlingswang/llm-rules/nextjs-development"><img src="https://agentmods.dev/badge/rules/ryanrawlingswang/llm-rules/nextjs-development.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 | $0.05257 | $0.05257 |
| Opus 5.5 | $0.02103 | $0.02103 |
| Sonnet 5.5 | $0.01051 | $0.01051 |
| Haiku 4.5 | $0.00526 | $0.00526 |
Grade A, and why
nextjs-development 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 1mo 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- nextjs-development — 97% identical, 4 lines differ
How it starts
The opening of the file, as written. The whole thing — 806 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Next.js Development Rules
You are an expert full-stack TypeScript engineer working with Next.js. Produce production-ready code that follows modern Next.js App Router patterns and best practices.
Tech Stack Guidelines
- Next.js 15+ (App Router) + React 19
- TypeScript (strict mode)
- Testing: Vitest + React Testing Library + MSW
- Styling: Tailwind CSS + shadcn/ui (when applicable)
- Package Manager: pnpm
Focus on: separation of concerns, strict typing, accessibility, performance, and comprehensive testing.
Project Structure
src/
├─ app/ # App Router (RSC by default)
│ ├─ _components/ # App-level (RSC-ok) components
│ ├─ api/ # API routes for external webhooks only
│ ├─ (routes)/ # Route groups and pages
│ └─ layout.tsx
├─ components/ # Reusable client/RSC components
│ ├─ ui/ # Base UI components
│ └─ [feature]/ # Feature-specific components
├─ lib/ # Utilities and shared helpers
├─ server/ # Server-side code
│ ├─ api/ # tRPC API layer
│ │ ├─ routers/ # tRPC router composition
│ │ ├─ procedures/ # Individual tRPC procedures
│ │ ├─ root.ts # Root router
│ │ └─ trpc.ts # tRPC setup
│ ├─ services/ # Business logic services
│ └─ clients/ # External service clients
├─ db/ # Database schema & migrations
├─ tools/ # AI tool definitions
├─ prompts/ # AI prompt templates
└─ trpc/ # tRPC client setup
test/
├─ unit/ # Unit tests
├─ integ/ # Integration tests
└─ e2e/ # End-to-end tests
Directory Conventions
- Use kebab-case for folders and files
- Co-locate tests next to source:
*.test.ts(x) - Export from
index.tsbarrels only when it helps DX without circular deps
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.
- 1mo ago First seen · 806 lines · 5,257 tokens per session scan A 9ac766d7c2b3
nextjs-development is a cursor rule published in the GitHub repository ryanrawlingswang/llm-rules (17 stars, last pushed 4mo ago), licensed MIT. It adds 5,257 tokens to every session, about $0.0210 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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