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 agentmods add rules/kaelsensei/magicaibuilder/general-principlesgit clone --depth 1 https://github.com/KaelSensei/MagicAIBuilderWrote 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/kaelsensei/magicaibuilder/general-principles)<a href="https://agentmods.dev/rules/kaelsensei/magicaibuilder/general-principles"><img src="https://agentmods.dev/badge/rules/kaelsensei/magicaibuilder/general-principles.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 | $0.00953 | $0.00953 |
| Opus 5 | $0.00477 | $0.00477 |
| Sonnet 5 | $0.00191 | $0.00191 |
| Haiku 4.5 | $0.00095 | $0.00095 |
Grade A, and why
general-principles 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 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.
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 — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.
General Principles and Project Philosophy
These rules define the core philosophy and mental model for MagicTheOfflining - a personal, offline-first React Native app for managing Magic: The Gathering Commander decks.
Project Philosophy
- This is a personal project, not production-grade enterprise software
- Prefer simple solutions over clever ones
- Avoid over-engineering
- If something can be done locally, do it locally
- Always assume the app must work offline
- This project is supposed to be fun, useful, and easy to maintain
- Keep it dumb. Keep it working. 😄
Mental Model
Cursor must assume:
- Scraping is allowed and mastered - HTML scraping and DOM parsing are core skills
- Data comes from unreliable HTML - Moxfield page structure must be understood, and data must be normalized
- Everything important is stored locally - SQLite and local filesystem are the source of truth
- Moxfield is read-only - Scraping only, no synchronization back to Moxfield
This app is:
- Offline - Works without internet after initial import
- Personal - No user accounts, no cloud sync, no authentication
- Fast - Prioritize speed and readability
- Simple - Functional screens > beautiful screens
If a suggestion violates one of these → don't do it.
Tech Stack Constraints
- Platform: React Native (Android first)
- Language: TypeScript (preferred) or JavaScript
- Local database: SQLite
- Scraping: HTML scraping (no official API)
- Image handling: local filesystem caching
- No backend server
- No authentication
- No cloud sync
Cursor must assume it fully masters:
- HTML scraping and DOM parsing
- Moxfield page structure and patterns
- SQLite usage in React Native
- Local file storage for images
If a suggestion requires a backend, cloud service, or external API → reject it.
Data Rules
- English card names only
- Commander decks only
- Moxfield is read-only (scraping only)
- No synchronization back to Moxfield
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 · 130 lines · 953 tokens per session scan A 43561fa2f1f2
general-principles is a cursor rule published in the GitHub repository KaelSensei/MagicAIBuilder (2 stars, last pushed 2d ago), licensed MIT. It adds 953 tokens to every session, about $0.0048 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.
Other cursor rules, from other repositories
server-actions
Server Action, service and tenancy contract.
project
Product, stack and layer contract. Always applies.
ui-design-system
UI, design tokens and mobile-first rules.
performance
Navigation, caching and PWA contract.
prisma-schema
Prisma schema and migration conventions.
git-flow
Branching, commits and PR hygiene. Always applies.