They act very much like the V'Shar of the Vulcan government; however, Ahm Tal operations are not confined to Andor. They are known to work on black-op missions, and Starfleet Intelligence has been known to sometimes receive related information from "anonymous sources."
The Ahm Tal was known to be a brutally efficient and doggedly determined part of the Andorian espionage branch. They were feared throughout the quadrant as alien spies, double agents, terrorists and moles were known to simply disappear when the Ahm Tal was involved. Andorian citizens often attribute such incidents to the Ahm Tal, and are often right. (Last Unicorn RPG module: The Andorians: Among the Clans, Decipher RPG module: Aliens)