given the existing specialist names, I'm not sure what you'd call it... Liaison or defector, or info courier, or something....
The following are sketches more than fully thought through.
If captured, and at a base, he would show his owner what is going on inside the enemy territory at some measure of distance from that base. (The defending player could then release him can and his view goes away).
Maybe also with this specialist, or some other one...
If he is gifted to another player, that player can see into the territory of the original owner, and the original owner can see into the gifted territory (either at a range or other measurement).
Just a thought.