This document discusses how to build a YellowAnt application with Ruby on Rails that allows users to manage a to-do list. It covers defining commands, handling user authentication through OAuth, processing commands by verifying tokens and checking event types, and formatting response messages with attachments, fields, buttons, and additional data. The example application will have commands to create, delete, get, list, and update to-do items, with the responses rendered back in the YellowAnt client.