Not a chat window — a role
A Buddy is not a box with a speech-bubble icon. It has a job, a name and a face — and it knows what it is responsible for and what it is not.
That sounds like decoration, but it is the point: something with a clear role can be clearly handed work. You do not say "the AI does marketing", you say "Orbit takes the enquiries". That can be checked, and it can be taken back.