Dhh Rails Style

What it does

When your agent uses it

• Ruby/Rails code generation
• Refactoring requests
• The user mentions DHH

Example prompts

• “clarity over cleverness”
• “/dhh-rails-style”

Workflow steps

8 steps, taken from the first numbered list in SKILL.md.

1. 1Controllers - REST mapping, concerns, Turbo responses, API patterns
2. 2Models - Concerns, state records, callbacks, scopes, POROs
3. 3Views & Frontend - Turbo, Stimulus, CSS, partials
4. 4Architecture - Routing, multi-tenancy, authentication, jobs, caching
5. 5Testing - Minitest, fixtures, integration tests
6. 6Gems & Dependencies - What to use vs avoid
7. 7Code Review - Review code against DHH style
8. 8General Guidance - Philosophy and conventions

What it can do on your machine

Read from SKILL.md and the folder at commit d0ffc6b. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are ruby).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Links to these hosts (documentation or services it may open):

  • github.com
  • x.com

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Dhh Rails Style loads about 1.7k tokens when it runs, and up to ~14k if it reads all its reference files. Until then it costs about 126 tokens; SKILL.md has 558 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~126

When it runs · the whole SKILL.md, loaded when a task matches

~1.7k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~14k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from davekilleen/Dex at commit d0ffc6b, republished under its MIT licence (© davekilleen). 558 words, ~1,703 tokens.

name

dhh-rails-style

description

This skill should be used when writing Ruby and Rails code in DHH's distinctive 37signals style. It applies when writing Ruby code, Rails applications, creating models, controllers, or any Ruby file. Triggers on Ruby/Rails code generation, refactoring requests, code review, or when the user mentions DHH, 37signals, Basecamp, HEY, or Campfire style. Embodies REST purity, fat models, thin controllers, Current attributes, Hotwire patterns, and the "clarity over cleverness" philosophy.

<objective>
Apply 37signals/DHH Rails conventions to Ruby and Rails code. This skill provides comprehensive domain expertise extracted from analyzing production 37signals codebases (Fizzy/Campfire) and DHH's code review patterns.
</objective>

<intake>
What are you working on?

<routing>

POST /cards/:id/close    → POST /cards/:id/closure
DELETE /cards/:id/close  → DELETE /cards/:id/closure
POST /cards/:id/archive  → POST /cards/:id/archival

# Symbol arrays with spaces inside brackets
before_action :set_message, only: %i[ show edit update destroy ]

# Private method indentation
  private
    def set_message
      @message = Message.find(params[:id])
    end

# Expression-less case for conditionals
case
when params[:before].present?
  messages.page_before(params[:before])
else
  messages.last_page
end

# Bang methods for fail-fast
@message = Message.create!(params)

# Ternaries for simple conditionals
@room.direct? ? @room.users : @message.mentionees

Card.joins(:closure)         # closed cards
Card.where.missing(:closure) # open cards

belongs_to :creator, default: -> { Current.user }

class User < ApplicationRecord
  def can_administer?(message)
    message.creator == self || admin?
  end
end

<credits>
Based on [The Unofficial 37signals/DHH Rails Style Guide](https://github.com/marckohlbrugge/unofficial-37signals-coding-style-guide) by [Marc Köhlbrugge](https://x.com/marckohlbrugge), generated through deep analysis of 265 pull requests from the Fizzy codebase.

© davekilleen, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 6 other files (references) in .claude/plugins/compound-engineering/skills/dhh-rails-style of davekilleen/Dex.

• SKILL.md
• references/architecture.md
• references/controllers.md
• references/frontend.md
• references/gems.md
• references/models.md
• references/testing.md

Open the folder on GitHubat commit d0ffc6b

Used in 1 other repository

We found 1 copy of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in davekilleen/Dex, which our catalogue first saw on October 7, 2026.

• NeverSight/learn-skills.devdata/skills-md/8b-is/8b-is-mp/dhh-rails-style