Skills are installed into your LLM (Claude, Cursor, OpenCode, etc) to give you new slash commands.

• Superpowers gives you commands for the full product lifecycle, from brainstorming, planning, execution, and review, using TDD and worktrees for parallelism.
• Superpowers (Ruby) is a fork of the above, tuned for Ruby/Rails applications (so proper idioms, 37signals/Basecamp code style patterns, etc.)
• Rails Upgrade Assistant from Ombu Labs / FastRuby.io, who do this for a living.