rails-concern

Generate TDD-oriented Rails ActiveSupport::Concern modules for shared model or controller behavior.

1|Updated Jan 8, 2026
One-click install
npx skills add https://github.com/LaunchPadLab/ai-bank --skill rails-concern-launchpadlab
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: rails-concern
Source: https://github.com/LaunchPadLab/ai-bank/tree/main/claude/skills/rails-concern
Command: npx skills add https://github.com/LaunchPadLab/ai-bank --skill rails-concern-launchpadlab

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

Rails apps often duplicate shared validations, scopes, callbacks, and helper logic across multiple models or controllers; this Skill helps you extract that duplication into reusable Rails concerns while keeping quality high through test-first development.

Core Features & Use Cases

  • TDD-first Rails concern creation: Start with a failing test, confirm RED, implement the concern, then confirm GREEN.
  • Model and controller concern workflows: Produces ActiveSupport::Concern modules suitable for both app/models/concerns and app/controllers/concerns.
  • Common concern patterns: Covers practical templates for UUID generation, soft deletion, search scopes, auditable tracking, and controller filters/helpers.
  • When to use: Extract shared behavior like validations and scopes across multiple models, or authentication/authorization and pagination/filter helpers across controllers.

Quick Start

Tell the AI to create a Rails concern and its test for a shared behavior you want extracted, including the test name, the module name, and whether it targets a model or a controller.

Frequently Asked Questions about rails-concern

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I extract duplicated Rails validations and scopes into a shared concern?▼

To extract duplicated Rails validations and scopes into a shared concern, generate an ActiveSupport::Concern module using test-first development. Start with a failing test, implement the reusable behavior, confirm GREEN, and save the module in app/models/concerns.

What's the best way to test Rails concerns using TDD?▼

The best way to test Rails concerns using TDD is to follow a RED-to-GREEN workflow. Define a failing test for the shared behavior, implement the ActiveSupport::Concern module, then verify the test passes for either model or controller integration paths.

Can I use a Rails concern to share authentication filters across controllers?▼

Yes, you can use a Rails concern to share authentication filters across controllers. Generate an ActiveSupport::Concern module for common controller filters and helpers, placing the tested module in app/controllers/concerns for reuse.

When should I use ActiveSupport::Concern instead of duplicating callbacks in Rails models?▼

Use ActiveSupport::Concern instead of duplicating callbacks when you need to extract repeated validations, scopes, or auditable tracking logic across multiple Rails models. Creating a concern keeps your application DRY and centralizes the shared behavior.

What common patterns can I extract into Rails concerns using this TDD approach?▼

Common patterns you can extract into Rails concerns using this TDD approach include UUID generation, soft deletion, search scopes, auditable tracking, and repeated controller filters. Each pattern is generated as a tested ActiveSupport::Concern module.

Do I need to write YAML frontmatter to create a Rails concern with this tool?▼

Yes, you need to define YAML frontmatter metadata and provide workflow instructions to create a Rails concern. This setup specifies the module name, testing path, and whether it targets a model or controller for proper generation.