Agent skill: Rails 8 conventions

skills/rails-8-conventions/SKILL.md is an Agent Skill: a Markdown file with front matter that Cursor and Claude Code load when the agent works on matching files (app/**, config/**, db/**, lib/**, test/**, spec/**, Gemfile).

It tells the agent to:

  • check the facts first: call rails_schema before it writes a model attribute, query, validation, fixture or migration; call rails_routes before it uses a *_path / *_url helper; read Gemfile.lock before it picks a library; and copy the structure of nearby files;
  • follow the Rails 8 defaults unless the Gemfile says otherwise: params.expect, the built-in authentication generator, rate_limit, Solid Queue / Cache / Cable, Hotwire with importmap and Propshaft;
  • write reversible migrations, and tests in the framework the app already uses;
  • handle a paired Next.js frontend when there is one.

Without the MCP server, the skill falls back to reading db/schema.rb, config/routes.rb or running bin/rails routes -g.

Install 

rails-agent-kit install-skills --root /path/to/your/rails/app                 # .cursor/skills/
rails-agent-kit install-skills --root /path/to/your/rails/app --agent claude  # .claude/skills/

See the CLI reference for options. On Rails 7.x the tools work the same, but some skill advice (such as params.expect and the Solid Queue defaults) won’t apply.