Rails Basecamp Engineer

Overview

This skill provides comprehensive guidance for building Ruby on Rails applications using 37signals/Basecamp coding patterns. These patterns emphasize composition over inheritance, concern-based organization, minimal controllers, rich domain models, and native Rails capabilities over external gems.

Core Principles

1. Composition over inheritance - Heavy use of concerns to compose behavior
2. Feature-driven organization - Group code by domain feature, not by layer
3. Minimal controllers - Push business logic to models and concerns
4. Rich domain models - Models are the heart of the application
5. Native Rails first - Prefer Rails features over external gems
6. Explicit over implicit - Clear, readable code over clever shortcuts
7. Transaction safety - Wrap critical operations in transactions
8. Event tracking - Record significant actions for audit trails

Working with Existing Applications

When working on an existing Rails application, detect which patterns are in use before loading reference files. If the current context doesn't reveal the approach, use an Explore agent to investigate.

Frontend/CSS Detection

Check for these indicators:

• tailwind.config.js or @tailwind directives → Load frontend/daisyui.md
• app/assets/stylesheets/_global.css with @layer → Load frontend/vanilla-css.md
• DaisyUI classes (btn, card, modal) in views → Load frontend/daisyui.md
• OKLCH colors or CSS custom properties → Load frontend/vanilla-css.md

Explore if unknown: Search for tailwind.config.js, @layer, or CSS file structure.

Multi-Tenancy Detection

Check for these indicators:

• Current.account or account_id scoping → Load multi-tenancy/shared-database.md
• activerecord-tenanted gem or Tenanted module → Load multi-tenancy/database-per-tenant.md
• URL path like /account-slug/... → Load multi-tenancy/shared-database.md
• Subdomain routing (tenant.app.com) → Load multi-tenancy/database-per-tenant.md
• No tenant scoping found → Load multi-tenancy/index.md for decision guide

Explore if unknown: Search for Current.account, tenant, account_id in models/controllers.

Authentication Detection

Check for these indicators:

• MagicLink model or magic_link routes → Load authentication/magic-link.md
• has_secure_password or password_digest → Load authentication/password.md
• Both present → Load both files

Explore if unknown: Search for MagicLink, has_secure_password, or session controllers.

Stimulus Controller Detection

When implementing frontend interactivity:

1. First check if similar controllers exist in app/javascript/controllers/
2. If no existing pattern, load stimulus/index.md for decision table
3. Load specific controller file based on need

Explore if unknown: List files in app/javascript/controllers/ to see existing patterns.

Reference Files

Load the appropriate reference when implementing specific patterns or domains:

Core Patterns

• references/models.md - Model patterns, concerns, associations, callbacks, scopes
• references/controllers.md - Controller patterns, concerns, filters, response handling
• references/current-attributes.md - CurrentAttributes pattern for request-scoped context
• references/routing.md - CRUD-everything routing philosophy, polymorphic URLs
• references/poros.md - Plain Old Ruby Objects patterns
• references/view-helpers.md - Stimulus-integrated view helpers

Domain-Specific Patterns

• references/authentication.md - Authentication overview and shared architecture
  • authentication/magic-link.md - Passwordless magic link (primary 37signals pattern)
  • authentication/password.md - Traditional password authentication
• references/authorization.md - Role-based and resource-level access control
• references/multi-tenancy/index.md - Multi-tenancy decision guide
  • multi-tenancy/shared-database.md - Shared DB with tenant_id filtering (Fizzy/Basecamp)
  • multi-tenancy/database-per-tenant.md - Separate DB per tenant

Frontend & Hotwire

• references/hotwire.md - Turbo Frames, Turbo Streams overview
• references/confirmation-dialogs.md - Native dialog confirmations with Turbo integration
• references/stimulus/index.md - Stimulus controller decision table
  • stimulus/utility-controllers.md - copy-to-clipboard, hotkey, toggle-class, beacon
  • stimulus/form-controllers.md - auto-submit, autoresize, local-save
  • stimulus/ui-controllers.md - dialog, lightbox, navigable-list, local-time
  • stimulus/interaction-controllers.md - drag-and-drop, sortable, resize
• references/frontend/index.md - CSS approach decision guide
  • frontend/vanilla-css.md - 37signals CSS (layers, OKLCH, design tokens)
  • frontend/daisyui.md - DaisyUI/TailwindCSS (uses Context7 for live docs)

Infrastructure

• references/background-jobs.md - Solid Queue configuration, recurring jobs, account context
• references/caching.md - HTTP caching (ETags), fragment caching, touch invalidation
• references/configuration.md - ENV patterns, multi-database, Solid Stack setup
• references/mailers.md - Minimal mailer patterns, bundled notifications

Other

• references/event-tracking.md - Audit trails, activity feeds, notifications, webhooks
• references/testing.md - Testing philosophy, fixtures, system tests, and helpers

Quick Decision Guide