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.
git clone --depth 1 https://github.com/proSamik/starterkit-nextjs-aisdk-betterauth-polarWrote 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/prosamik/starterkit-nextjs-aisdk-betterauth-polar/project-info)<a href="https://agentmods.dev/rules/prosamik/starterkit-nextjs-aisdk-betterauth-polar/project-info"><img src="https://agentmods.dev/badge/rules/prosamik/starterkit-nextjs-aisdk-betterauth-polar/project-info/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/prosamik/starterkit-nextjs-aisdk-betterauth-polar/project-info"><img src="https://agentmods.dev/badge/rules/prosamik/starterkit-nextjs-aisdk-betterauth-polar/project-info.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 | $0.06209 | $0.06209 |
| Opus 5.5 | $0.02484 | $0.02484 |
| Sonnet 5.5 | $0.01242 | $0.01242 |
| Haiku 4.5 | $0.00621 | $0.00621 |
Grade A, and why
project-info 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 2mo 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 — 638 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Polar SaaS Kit - Cursor AI Development Rules
Updated: January 2025
Project Overview
Polar SaaS Kit is a production-ready Next.js starter for building modern SaaS applications with payments, authentication, and premium features. Built with Next.js 15, Better Auth, Polar.sh payments, and PostgreSQL.
Core Architecture & Constraints
1. Framework & Technology Stack
- Next.js 15.3.2 with App Router (REQUIRED)
- TypeScript 5.8.3 - Strict mode enabled (NO JavaScript files)
- React 19.1.0 with concurrent features
- Better Auth 1.2.8 for authentication (NO next-auth)
- Polar.sh for payments and billing (NO Stripe)
- PostgreSQL + Drizzle ORM for database (NO Prisma)
- Tailwind CSS 4.1.8 for styling (NO other CSS frameworks)
- Biome for linting/formatting (NO ESLint + Prettier)
- Vercel AI SDK for AI chat integration (NO custom AI implementations)
2. Project Structure Constraints
Authentication (NEVER modify core auth structure)
src/lib/auth/
├── server.ts # Better Auth server config - DO NOT CHANGE POLAR SETUP
├── client.ts # Better Auth client config - POLAR ERROR FILTERING ACTIVE
Database (ALWAYS use repository pattern)
src/lib/db/
├── pg/
│ ├── schema.pg.ts # Schema definitions - ADD FIELDS, DON'T REMOVE
│ ├── db.pg.ts # Connection config
│ └── repositories/ # Data access layer - USE FOR ALL DB OPERATIONS
App Structure (FOLLOW EXACT PATTERNS)
src/app/
├── (auth)/ # Public auth pages (sign-in, sign-up)
├── (premium)/ # Protected premium app pages
│ └── app/ # Main app interface with sidebar
├── api/auth/ # Better Auth API routes - DON'T MODIFY
├── pricing/ # Landing page pricing
├── page.tsx # Landing page
└── layout.tsx # Root layout with theme provider
Component Organization (REUSE EXISTING COMPONENTS)
src/components/
├── ui/ # Radix UI + shadcn components - REUSE THESE
├── layouts/ # Layout components (app-sidebar, theme-provider)
├── landing/ # Landing page sections - MODIFY THESE FOR FEATURES
├── dashboard.tsx # Dashboard component with stats
├── profile.tsx # User profile component
└── settings.tsx # Settings with theme selection
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.
- 2mo ago First seen · 638 lines · 6,209 tokens per session scan A 94ac103392eb
project-info is a cursor rule published in the GitHub repository proSamik/starterkit-nextjs-aisdk-betterauth-polar (4 stars, last pushed 1y ago), licensed MIT. It adds 6,209 tokens to every session, about $0.0248 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 2026-08-31.
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