Diplomacy, battles, etc., are not available as semantic data. Nor are things like number of nobles, gold incomes, food or trade statistics.
Actually, I should say that these are not available as automaticly updated values. We could create semantic data for them, but it would all be manually updated. Thus subject to the same "quickly out of date" problems as lots of other things.
You can see the types of info available as "live data" by going to the wiki and going to the semantic wiki" page. From there, look for the External Data API link. Somewhere around there it lists all the data that can be extracted directly from the game database in real-time. If there is something else you want, let us know. Just open a new thread on the wiki board. Remember that we won't make anything like income or CS data available.