User Agent - (1) The EBIF user agent is the computer code residing in a set-top box or equivalent device, that receives "triggers," which display on-screen graphics and return viewer's responses. But there are a variaty of user agents.

(2) The fields in a web server log file that record information such as what browser and platform visitors are using.

Intelligent Agent

Knowbot - (Knowledge Robot)

Script (Calling Script)

Sweep Tool