The trickiest part about writing Thief Ai versus Guard Ai so far has been providing a form of automated Navigation through shadows. That is have to have ThiefAi aware of the lighting level around them so that they know if they're likely to blunder into a brightly lit corridor, and/or to take the darkest path (not necessarily the shortest) from point A to B.
Now I know not everyone gets their jollies off solving obscure bot navigation problems, but it keeps me busy enough.
The ultimate aim for ThiefAi is to end up as a functional bot that hunts for loot, ambushes human players and knows when not to fight a losing battle.
Hopefully this will equate to an enjoyable game experience to play against for those who just wouldn't be caught dead playing as a cowardly thief :)
-:-
