We've been experimenting with various skills and MCPs in our day-to-day Ruby development at Poll Everywhere. This is the internal skill that's been most useful for preserving the context window while letting agents explore Ruby code.

It's a CLI wrapper around Ruby's Prism gem that lets the agent do this:

  $ prism -o app/models/user.rb

  User < ApplicationRecord [1-75]
    includes Agreeable
    includes Auditable
    has_many :polls
    has_many :questions, through: :polls
    has_many :votes
    has_many :reports, dependent: :destroy
    #audit_create [41-43]
    #allowed_to_participate_in?(poll) [45-66]
    #restricted_from_participation_in?(poll) [68-70]
    #recently_created? [72-74]

  $ prism -m 'recently_created?' app/models/user.rb

  === METHOD: recently_created? ===
  Lines 72-74:
    def recently_created?
      created_at.after?(5.minutes.ago)
    end

The idea is to give the agent a token-efficient way to understand what's going on in Ruby code.