How to build a phone answering AI assistant

Alexander Krastev · 2026-09-22

A phone assistant is four pieces: something that answers the line, ears that turn speech into text, a brain that decides what to say, and a mouth that says it. In AIK all four are already wired together; what follows is what you choose and what you have to bring yourself.

The line

AIK answers calls through a telephony provider — you buy a number there, and point its "a call comes in" setting at your AIK address. That is the one part that is not free and not ours: a number and per-minute charges belong to whoever sells you the line. The same number can also take SMS and WhatsApp messages, answered by the same assistant.

Ears and mouth: free, or paid, and they are chosen separately

Ears and mouth are separate settings on purpose: local listening with a paid voice, or the other way round, is a normal choice.

The brain

The same model your other agents use. The assistant has a persona you write in plain words — who it is, what it may promise, when to take a message — and a set of tools: it can look something up, write to a spreadsheet, or book a slot in a calendar while the caller is still on the line.

What it says before it says hello

Every incoming call opens with a sentence saying the caller is talking to an AI assistant, and every outbound call the same — that one is in code and cannot be switched off or written out of the persona, because the EU AI Act asks for it and a persona is editable. Every turn of every call is written to a tamper-evident log, so "what did it tell that customer?" has an answer.

An AI receptionist on your own number

An AI phone assistant is the receptionist that never goes to lunch: it answers, says it is an AI, takes the order or the question, and hands anything it cannot handle to you. The same Assistant can answer your website chat, SMS and WhatsApp, so a customer gets the same answers everywhere.

Setting it up

Assistants → pick or duplicate one → write the persona → choose the engines → paste the phone number. There is a browser call button on the page, so you can hear it before any real caller does. The voice settings are one shared installation-wide set; each assistant can override the persona and language.

Trying it

You can try AIK for free at aikautomation.com — the browser call works without a phone number at all, which is the quickest way to hear it. To have it on your own computer or server, with the free speech engines installed and a number connected, you buy a licence and we install it for you. Get in touch.

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