The work it is built for
Greet the caller with your name and whether you are open, at lunch, or closed. Answer hours, address, services, and the prices you approved. Hear the request and restate it. Collect a name and callback number. Take a message. Transfer to a department or a named person when the office is open. Capture an appointment request or an order when you have defined where that request goes.
Across industries the motion is the same. A pizza order goes to the cook. A billing question goes to billing. A parts question stays inside the inventory you provided. A parent with a simple after-hours concern can be offered the care guide you approved, and a complicated one goes to the on-call nurse as a message.
The work it must refuse
It should not quote a price you did not write, describe a car that is not on the list, or give a medication dose. If the note is missing, the right sentence is 'I don't have that, and I can take a message.' That restraint is what makes the rest believable.