I'm playing Beyond The Sword and when I want to build a spy I notice they supposedly: Helps Thwart Rival Spies:
Should I leave a spy stationed at borders? Should I place them cities? Does it matter where they are placed in order to effectively thwart rival spies? I can't seem to find any correlation to where I put them and my success rate of stopping incoming espionage.
The reason I ask is because I'm playing a world-scenario starting in 1000 as the Indian empire and the starting borders are all mountainous, that is, there are very few entrances I have to guard. They are quick to train and I'm getting constantly attacked by spies – not just in my cities but also towns, watch-towers, farms, etc.
Update:
I'm not sure if this has to do with anti-spy buildings (e.g. Intelligence Agency) or because I've stationed a spy in every city, but I'm seeing a huge increase in these messages:
Best Answer
If you have a spy in your city, it helps increase the cost for enemy spies to do an action in that city, and also helps albeit rarely for you to detect the enemy spy.
I'd put them in my cities if I was worried about espionage but they seem to be more productively used offensively then defensively for the slight improvement they make helping "thwart rival spies".
I have never placed them at borders, I'd imagine this would be a lot of work for the same detection with less done to actually prevent or increase cost of attacks.
Overall you can't stop them from running missions on you, but using spies this way increases their cost making it become very expensive for them to continue to do so.