Spy has own veteran levels in classic, experimental, civ2civ3, and multiplayer rulesets.
spymaster > agent > handler > informant
But an "agent" is the person who is ordered by handler and executes missions.
Therefore,
spymaster > intelligence officer > handler > agent > informant
this ranks are more accurate.
ref:
http://www.spymuseum.org/education-prog ... espionage/
https://en.wikipedia.org/wiki/Espionage ... _espionage