blueprint.rb

module Mcl
  class HMclCBSBuilder
    class Blueprint
      # ...
    end
  end
end

cbs_builder.rb

module Mcl
  class HMclCBSBuilder < Handler
    module Commands
      def com_load player, args
        bp, url = current_blueprint(player), args[0]

        load_blueprint(url) do |blueprint, ex|
          # ...
        end
      end
    end
    include Commands

    module Helper
      def load_blueprint url, &callback
        blueprint = ::Mcl::HMclCBSBuilder::Blueprint.new(content)
        # NameError: uninitialized constant Mcl::HMclCBSBuilder::Blueprint
      end
    end
    include Helper
  end
end

printer.rb

module Mcl
  class HMclCBSBuilder
    class Printer
      # ...
    end
  end
end