Yea, that's there to prevent future breakage if someone forgets to put command_summary on a CLI class.  I could also use respond_to?

Which of these do you prefer?

        summary = if Heirloom::CLI.const_get(klass).respond_to? 'command_summary'
                    Heirloom::CLI.const_get(klass).command_summary
                  else
                    'No summary available'
                  end

or

        summary = begin
                    Heirloom::CLI.const_get(klass).command_summary
                  rescue NoMethodError
                    'No summary available'
                  end

or something else? :)