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/nedcodes-ok/cursorrules-collectionWrote 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/nedcodes-ok/cursorrules-collection/rails)<a href="https://agentmods.dev/rules/nedcodes-ok/cursorrules-collection/rails"><img src="https://agentmods.dev/badge/rules/nedcodes-ok/cursorrules-collection/rails/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/nedcodes-ok/cursorrules-collection/rails"><img src="https://agentmods.dev/badge/rules/nedcodes-ok/cursorrules-collection/rails.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 | $0.00285 | $0.00285 |
| Opus 5.5 | $0.00114 | $0.00114 |
| Sonnet 5.5 | $0.00057 | $0.00057 |
| Haiku 4.5 | $0.00028 | $0.00028 |
Grade A, and why
rails 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.
What it actually says
Ruby on Rails Cursor Rules
You are an expert Rails developer. Follow these rules:
Architecture
- Fat models, skinny controllers
- Service objects for complex business logic
- Concerns for shared behavior — keep focused
- Form objects for complex multi-model forms
Models
- Database-level constraints + validations
- Scopes for reusable queries:
scope :active, -> { where(active: true) } - Enums with prefix option. Indexes on FKs and frequent queries
- counter_cache for belongs_to with displayed counts
Controllers
- before_action for shared setup. Strong parameters always
- Appropriate HTTP status codes
- Standard 7 RESTful actions. Extract non-REST to new controllers
Active Record
- includes() to prevent N+1. Bullet gem to detect
- find_each for batch processing. Transactions for multi-record ops
- pluck() for specific columns without full objects
Background Jobs
- Active Job + Sidekiq. Make jobs idempotent
- Pass IDs, not objects. Set queue priorities and retries
Testing
- RSpec + FactoryBot with traits
- shoulda-matchers for model tests
- VCR/WebMock for HTTP. Test happy path, edges, auth
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 · 41 lines · 285 tokens per session scan A 7ea692a39b85
rails is a cursor rule published in the GitHub repository nedcodes-ok/cursorrules-collection (38 stars, last pushed 7mo ago), licensed MIT. It adds 285 tokens to every session, about $0.0011 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.
Other cursor rules, from other repositories
10-backend-fastapi
FastAPI backend rules.
laravel-php-auto
Laravel and PHP Development Standards.
04-kotlin
Cursor rule "04-kotlin" from orbitalsonic/AndroidPilot, covering kotlin rules, prefer, coroutines, null safety and naming.
express
Express/Node.js best practices.
python
Python best practices.
typescript
TypeScript best practices.