Not sure AddAction is a good name. The word "tag" should appear here. E.g. AddTaggedAction, AddActionByTags... 

Also, I think it would be good to include a disclaimer in the class doc about what "Adds an action" means. I know it's quite plain in the libgdx world, but it can be misleading for some (after all, that "add" does not simply involves adding an action to the game model, but to schedule its execution, right?)