Tok'ra Couriers were half diplomats and half operative members of their species, who would be the balance between the Tok'ra Councilors and the deep cover agents. The couriers were the ones who took new orders from the secret Tok'ra base to the field. They would return with new information from their contacts and allies; reporting this information to the councilors.
When deployed, the couriers required pre-existing stories for their assignments, as they did not have time to develop an intricate background story. This, combined with their own ingenuity, allowed them to infiltrate the ranks of the Goa'uld. (RPG: "Friends and Foes: Stargate Season Two")