37signals Skills
37signals Skills is an unofficial collection of agent skills and a reference guide that teach AI coding assistants to write Ruby on Rails the way 37signals does, extracted from its Fizzy and Campfire codebases and DHH's code reviews.
37signals Skills packages Rails coding conventions as agent skills for Claude Code and Cursor, covering architecture and naming, Hotwire realtime features (Turbo, Stimulus, ActionCable), Active Job patterns, safe migrations, multi-tenant security, Minitest-based testing, and webhook delivery. An additional skill reviews code in the style of DHH's own reviews, invoked as a slash command.
The core skill activates automatically for Rails work, while the more specific skills are marked for on-demand, explicit invocation so they do not add to every request. It installs by copying skill folders into a project's or a user's Claude Code or Cursor skills directory, or into Codex's skills directory.
It is an unofficial community project based on 37signals' public code and discussions, and is not affiliated with or endorsed by 37signals.