I'm trying to make agents run around a room, on the walls, ceiling etc but I cant seem to get my agents to start outside the room and come inside and follow the walls as a terrain...

They just walk forward and off. I used an example file to see where i was going wrong and it seems as though the issue is that the corners are too sharp? it works on a sphere but not a box.

Any help is appreciated.

Thanks.

Yeah, the terrain projection is based on raycasting so you're likely correct that the sharp corners are the problem.
I'd maybe try using some proxy geometry for the terrain where the corners are smoothed out? You might want that anyways so that the agent turns in a smoother manner instead of snapping quickly to the new up vector