Pre-programmed countries have spies.

Try this when you are in a boring game and happen to be at war with a non-player country on your border;

Move the garrison from a border province that is out of view from the enemy.

Observe that the “intelligent” agent will send troops to capture the “vacant” province center. This can happen even if your units are a short time away from the province center. Move the garrison, and any additional troops nearby back into the province center, the enemy will continue to the province center. Very “intelligent”!