Word add-in - determining file that is currently loaded

My company is interested in extending some of the functionality of Box Edit. Once a Word doc has been opened, we'd like to pull up metadata or version history, for example. 

Any examples of add-ins that do this sort of thing? If not, how could a new Word add-in determine the id for a document that's been opened through Box Edit so additional BOX API functions could be performed on it?