So I had a couple enemy spies camping on my tech planet.  I built a counter espionage center on the planet.  That is supposed to nullify spies, correct?  Or will it only prevent them from setting up spies there, not remove them if they are already in place?  Because it didn't remove them.  I had to remove them manually by using up agents, several turns after the counter espionage building had been set up.  Is this intentional?  Is there any way to remove spies from my planet without resorting to using my agents?

Or were the effect of the spies nullified, even though the spies still showed up on my planet that had the counter espionage center?  Could I have avoided using up agent to remove the enemy spies?