A clone advisor was an individual who served as an advisor to a clone commando squad. Their duty was to inform the squad about their missions, status, and objectives.
Besides actual clone troopers, it was rumored that some or all of the Cuy'val Dar were used as clone advisors during the Clone Wars. Because of the secrecy surrounding these individuals, knowledge is scarce as to their official role as support personnel.
The exact nature of this role is currently unknown. It may be that it is an official position within the Grand Army of the Republic, or it may be simply a position that is filled by a qualified trooper as the need arose. It is not clear if all clone commando squads used a clone advisor, but the known example that did use one did not do so for all of their missions.