rails-cursorrules-prompt-file

rails-cursorrules-prompt-file is a cursor rule for Cursor from PatrickJS/awesome-cursorrules. It costs 150 tokens per session, scanned A, original, CC0-1.0.

A set of Cursor coding rules for developing applications with Rails 8, a Ruby web framework. It covers Rails conventions, PostgreSQL, Hotwire, testing with Minitest, local development, and deployment with Kamal.

In plain words
What is it for?
Use it when building Rails models, controllers, migrations, database-backed features, interactive pages, tests, and local or deployed environments.
Why use it?
It guides the assistant toward the project's preferred Rails structure and tools, reducing boilerplate and inconsistent implementation choices.

Cursor rule for Cursor

Written for Cursor: a Cursor rule (.mdc). Also seen: mentions Cursor.

Good fit Use it when building Rails models, controllers, migrations, database-backed features, interactive pages, tests, and local or deployed environments.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/patrickjs/awesome-cursorrules/rails-cursorrules-prompt-file
About the project

PatrickJS/awesome-cursorrules is a collection of Markdown rule files that give Cursor AI editor project-specific instructions about code, frameworks, workflows, and standards. Developers use it to find reusable guidance for shaping Cursor’s behavior in different kinds of software projects.

PatrickJS/awesome-cursorrules · 40,734 stars · on GitHub

Install

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.

Clone the repo
git clone --depth 1 https://github.com/PatrickJS/awesome-cursorrules

Made for: Cursor.

Wrote 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.

agentmods badge for rails-cursorrules-prompt-file

README.md
[![agentmods](https://agentmods.dev/badge/rules/patrickjs/awesome-cursorrules/rails-cursorrules-prompt-file.svg)](https://agentmods.dev/rules/patrickjs/awesome-cursorrules/rails-cursorrules-prompt-file)
Your own site
<a href="https://agentmods.dev/rules/patrickjs/awesome-cursorrules/rails-cursorrules-prompt-file"><img src="https://agentmods.dev/badge/rules/patrickjs/awesome-cursorrules/rails-cursorrules-prompt-file.svg" alt="Measured on agentmods" height="20"></a>
Per session 150 This file is loaded in full into every session.
When invoked 150 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00150 $0.00150
Opus 5 $0.00075 $0.00075
Sonnet 5 $0.00030 $0.00030
Haiku 4.5 $0.00015 $0.00015

Measured 3d ago against content hash ed070bfa7b97, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

rails-cursorrules-prompt-file 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 3d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

rules/rails-cursorrules-prompt-file.mdc · 15 lines

What it actually says

Rails 8 Development Guidelines

  • Prefer Rails command-line generators over hand-written boilerplate.
  • Use bin/dev for local development and check logs after significant changes.
  • Follow Rails 8 conventions for Solid Queue, Solid Cache, Solid Cable, Propshaft, and Kamal where appropriate.
  • Keep controllers RESTful and focused; use service objects for complex business logic.
  • Use PostgreSQL, proper indexes, connection pooling, and safe migrations.
  • Write Minitest coverage for models, controllers, and integration flows.
  • Use Hotwire for standard Rails interactivity and Vite only when npm-managed JavaScript is needed.
Changes

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.

  1. 3d ago First seen · 15 lines · 150 tokens per session scan A ed070bfa7b97

Subscribe to this mod's changes

rails-cursorrules-prompt-file is a cursor rule published in the GitHub repository PatrickJS/awesome-cursorrules (40,734 stars, last pushed 3mo ago), licensed CC0-1.0. It adds 150 tokens to every session, about $0.0007 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 2026-09-03.