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37signals-rails

37signals-rails is a skill for Claude Code, Codex from pproenca/dot-skills. It costs 105 tokens per session (1,984 once invoked), scanned A, original, MIT.

A set of Ruby on Rails coding guidelines based on the conventions used by 37signals, the company behind Basecamp, HEY, and Fizzy. It covers controllers, models, views, database design, background jobs, caching, authentication, and Turbo or Stimulus features.

In plain words
What is it for?
Use it when writing, reviewing, or refactoring Rails controllers, models, views, database schemas, jobs, authentication, or real-time interface code.
Why use it?
It helps Rails teams make consistent design choices and avoid adding unnecessary layers or dependencies. The guidance favours Rails' built-in patterns and rich domain models.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions AGENTS.md.

not rated 206repo +4 25d ago A scan SkillSpector: pass 105 tokens original MIT

Good fit Use it when writing, reviewing, or refactoring Rails controllers, models, views, database schemas, jobs, authentication, or real-time interface code.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/pproenca/dot-skills/37signals-rails
View source ↗ pproenca/dot-skills
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.

Any agent
npx skills add pproenca/dot-skills --skill 37signals-rails
Clone the repo
git clone --depth 1 https://github.com/pproenca/dot-skills

Made for: Claude Code, Codex.

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 37signals-rails

README.md
[![agentmods](https://agentmods.dev/badge/skills/pproenca/dot-skills/37signals-rails/github.svg)](https://agentmods.dev/skills/pproenca/dot-skills/37signals-rails)
Your own site
<a href="https://agentmods.dev/skills/pproenca/dot-skills/37signals-rails"><img src="https://agentmods.dev/badge/skills/pproenca/dot-skills/37signals-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.

agentmods 80×15 button for 37signals-rails

Your own site · 80×15
<a href="https://agentmods.dev/skills/pproenca/dot-skills/37signals-rails"><img src="https://agentmods.dev/badge/skills/pproenca/dot-skills/37signals-rails.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 105 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,984 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00105 $0.01984
Opus 5 $0.00053 $0.00992
Sonnet 5 $0.00021 $0.00397
Haiku 4.5 $0.00011 $0.00198

Measured 10d ago against content hash 1dc2e2c490cd, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

37signals-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 10d 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.

skills/.experimental/37signals-rails/SKILL.md · 131 lines

How it starts

The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.

37signals Rails Best Practices

Comprehensive coding principles and conventions for Ruby on Rails applications, as practiced at 37signals (Basecamp, HEY, Fizzy). Contains 56 rules across 8 categories, prioritized by architectural impact. Derived from official 37signals sources: the Fizzy codebase, STYLE.md, AGENTS.md, the Rails Doctrine, DHH's "On Writing Software Well" series, and the unofficial 37signals style guide (265 Fizzy PRs).

When to Apply

Reference these guidelines when:

  • Writing new Rails controllers, models, or views
  • Deciding between gems and vanilla Rails
  • Modeling state and database schema
  • Setting up background jobs, caching, or real-time features
  • Reviewing code for 37signals-style conventions
  • Refactoring toward rich domain models
  • Choosing authentication or authorization approach
  • Adding Stimulus controllers or Turbo patterns

Rule Categories by Priority

Priority Category Impact Prefix
1 Architecture Fundamentals CRITICAL arch-
2 Controllers & REST CRITICAL ctrl-
3 Domain Modeling HIGH model-
4 State Management HIGH state-
5 Database & Infrastructure HIGH db-
6 Views & Frontend MEDIUM view-
7 Code Style MEDIUM style-
8 Testing MEDIUM test-

Quick Reference

1. Architecture Fundamentals (CRITICAL)

Read the full file on GitHub · 131 lines

Files

What ships with it

59 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 10d ago First seen · 131 lines · 105 tokens per session scan A 1dc2e2c490cd

Subscribe to this mod's changes

37signals-rails is a skill published in the GitHub repository pproenca/dot-skills (206 stars, last pushed 25d ago), licensed MIT. It adds 105 tokens to every session and 1,984 once invoked, about $0.0005 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 2026-08-30.

Backend and APIsLanguagesRuby
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