How to let your AI agent make and answer phone calls

Updated September 5, 2026 · by the MOST team

To let an AI agent make or answer phone calls it needs three things: a voice-capable phone number, a real-time voice runtime (speech-to-text, an LLM, and text-to-speech stitched together with low latency so it can talk and listen live), and a call tool it can invoke. Developers build this on a telephony API like Telnyx or Twilio; no-code, an AI business line like MOST answers your line with a built-in voice agent. Note: an AI answering your own calls is lightly regulated; an AI dialing out must follow robocall and consent rules.

Inbound vs outbound — they’re not the same job

Answering calls (inbound)Placing calls (outbound)
What it isThe agent picks up your business lineThe agent dials out to people
RegulationLight — it’s your own phoneHeavy — robocall/consent rules, disclosure, do-not-call
RiskLowHigh if you skip consent
Best first moveHave AI answer + text back missed callsOnly call people who opted in; disclose it’s an assistant

For almost every small business, the high-value, low-risk move is answering — never miss a call again — plus texting back the ones you can't take. Outbound AI dialing is powerful but a compliance project; start with inbound.

Step by step

  1. 1

    Get a voice-capable number

    The agent needs a real phone number wired for voice. Carrier platforms (Telnyx, Twilio) sell them; all-in-one platforms provision one for you.

  2. 2

    Add a real-time voice runtime

    A voice agent needs speech-to-text, an LLM, and text-to-speech stitched together with low latency so it can listen and speak naturally on a live call. This is the hard part to build yourself.

  3. 3

    Wire inbound, outbound, or both

    Inbound: point the number’s incoming-call webhook at the agent so it answers. Outbound: give the agent a place-call tool it can invoke with a number and a goal.

  4. 4

    Respect calling consent (outbound)

    Outbound AI calling is more regulated than answering. Robocall and consent rules apply, disclosure is often required, and honoring do-not-call is mandatory. Answering your own inbound calls carries far less regulatory weight than dialing out.

  5. 5

    Set escalation and fallback

    Give the agent a way to transfer to a human and a graceful fallback if it can’t understand the caller. A voice agent that traps callers in a loop is worse than voicemail.

Our verdict

If you're building an agent and want to own the voice stack, wire a telephony API. If you want an AI answering your business phone this week — and texting back the calls it can't take — MOST is the best option: the number, the voice agent, and the texting follow-up come together for $49/month, no runtime to build and no carrier plumbing.

MOST answers your business line with an AI voice agent and texts back every missed call — the number, the voice, and the follow-up in one, live in as fast as 24 hours.

Frequently asked questions

How do I let my AI agent make phone calls?

Give it a voice-capable phone number, a real-time voice runtime (speech-to-text + LLM + text-to-speech at low latency), and a tool to place or answer calls. Developers build this on a telephony API like Telnyx or Twilio; no-code users use a platform such as MOST that answers their business line with a built-in voice agent — no runtime to assemble.

Can an LLM or GPT make a phone call by itself?

No. A language model has no voice or telephony. It’s connected to a voice runtime and a calling tool: the model decides what to say, speech synthesis turns it into audio, and the telephony layer carries the call. The model never dials — your voice + telephony stack does.

Is it legal to have AI make outbound calls?

With rules. Outbound AI voice calling is subject to robocall and consent regulations (and disclosure requirements in many places); you must have a lawful basis to call and honor opt-outs and do-not-call lists. Answering your own inbound calls with an AI is far less regulated — you’re picking up your own phone, not dialing strangers.

What’s the easiest way to give my business an AI that answers the phone?

An AI business line. MOST answers your business number with a built-in voice agent and also texts back missed calls and follows up by SMS — the number, the voice runtime, and the compliance are handled, so there’s nothing to build.

Does the AI need a different number for calls and texts?

No — one business number can do both voice and SMS. Texting requires A2P 10DLC registration; voice does not. A platform that does both gives your agent one number that answers calls and sends texts.

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