# Mailer Patterns

Creates minimal Action Mailer classes with bundled notification patterns following...

- Repository: https://github.com/ThibautBaissac/rails_ai_agents (671 stars)
- Category: Engineering
- License: MIT
- Last updated: 2026-06-01
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add ThibautBaissac/rails_ai_agents --skill mailer-patterns -g -a claude-code -y`
Codex: `npx skills add ThibautBaissac/rails_ai_agents --skill mailer-patterns -g -a codex -y`
Cursor: `npx skills add ThibautBaissac/rails_ai_agents --skill mailer-patterns -g -a cursor -y`
Gemini CLI: `npx skills add ThibautBaissac/rails_ai_agents --skill mailer-patterns -g -a gemini-cli -y`

## Description

Creates minimal Action Mailer classes with bundled notification patterns following 37signals conventions. Use when sending emails, creating notification systems, digest emails, or when user mentions mailers, emails, notifications, or transactional messages. WHEN NOT: For background job scheduling (use job-patterns), for event-driven triggers (use event-tracking).

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Mailer Patterns

## Philosophy: Minimal Mailers, Bundled Notifications

- Plain-text first, minimal HTML styling with inline CSS
- Bundle notifications instead of sending one email per event
- Transactional emails only (no marketing campaigns)
- `deliver_later` for individual emails; `deliver_now` is acceptable inside background jobs that already run asynchronously (e.g., digest delivery jobs)
- Email previews for development
- No email service abstraction layers (use Action Mailer directly)

## Project Knowledge

**Stack:** Action Mailer (built-in), Solid Queue for background delivery,
email previews in development, plain text + HTML multipart emails.

**Multi-tenancy:** Account-scoped emails, from address includes account
context, unsubscribe links scoped to account.

**Commands:**
```bash
rails generate mailer Comment mentioned         # Generate mailer
rails generate mailer Digest daily_activity      # With methods
# Visit http://localhost:3000/rails/mailers      # Preview emails
```

## Pattern 1: Simple Transactional Mailers

```ruby
# app/mailers/application_mailer.rb
class ApplicationMailer < ActionMailer::Base
  default from: ENV.fetch("MAILER_FROM_ADDRESS", "Fizzy <support@fizzy.do>")
  layout "mailer"
end

# app/mailers/comment_mailer.rb
class CommentMailer < ApplicationMailer
  def mentioned(mention)
    @mention = mention
    @comment = mention.comment
    @card = mention.comment.card
    @account = mention.account

    mail(
      to: mention.user.email,
      subject: "#{mention.creator.name} mentioned you in #{@card.title}"
    )
  end

  def new_comment(comment, recipient)
    @comment = comment
    @card = comment.card
    @account = comment.account

    mail(
      to: recipient.email,
      subject: "New comment on #{@card.title}"
    )
  end
end

The rest: https://github.com/ThibautBaissac/rails_ai_agents/blob/HEAD/.claude_37signals/skills/mailer-patterns/SKILL.md