They aren't unique to the culture, the series just focuses almost solely on the culture. The few other perspectives we get to look at (e.g. the Idirans in Consi

They aren't unique to the culture, the series just focuses almost solely on the culture. The few other perspectives we get to look at (e.g. the Idirans in Consider Phlebas) are bloody fanatics who prefer to conquer their enemies in martial combat, not spies. Even within the Culture, special circumstances exists as a pragmatic necessity at odds with the broader society of the Culture. It's pointed out many times that its existence and methods are controversial and widely distrusted. I think the only real glimpse we get of other civilizations' versions are in Surface Detail, where it's mentioned (but never directly observed) that the other side of the war has agents influencing events exactly like the culture does.