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Introducing built-in AI voice agents

· 7 min read
Nader Jaber
Nader Jaber
Head Honcho @ FlyNumber

Back in 2024 I wrote a post about AI and said "Imagine having an AI agent answer calls off business hours." I also said that if you were technically inclined, you could do it right then.

A lot of you did. More and more of you have been hooking your FlyNumber up to VAPI, ElevenLabs and the like over SIP. It works, but now you've got a second account, a second bill and SIP settings that have to be exactly right. Most people just want an AI answering their number, quickly, without all that.

So we built it in. Finally. As of today your FlyNumber can be answered by an AI voice agent, set up right inside the panel. It's in beta, and I'm pretty excited about it.

The Rules tab for a bike repair shop agent: an opening line, four rule cards (just answer price questions, transfer to the owner, take a message, end the call when the caller is done), and the How a call goes panel beside them showing the recorded greeting, the opening line, each rule's action, the fallback and the 5-minute limit.
A few plain rules, and the whole call laid out on the right.

What it does​

It picks up your calls, answers questions from what you've told it, takes messages, transfers callers to you when they ask, and says goodbye when they're done. Doesn't matter if it's a shop, a team or just your personal number.

A typical call goes something like this: the caller asks what your hours are, the agent tells them, the caller says "okay, thanks, that's all", and the agent says bye and hangs up. If they want a human, it transfers them to you.

Every call starts with a short recorded greeting, "Hi, you've reached an AI assistant." You pick its language, but the words can't be changed. The reason for this is twofold: 1) the EU and other countries are regulating this type of thing, and they want AI assistants to make it clear they're AI. 2) From a moral perspective, I think callers should know they're talking to AI - the underlying technology is the latest and greatest when it comes to AI voice LLMs. It's REALLY good, and many people could be fooled into thinking they're talking to a human. We have our own account screening process, but this is a layer we felt was worth adding. After the greeting, the agent can be set to say whatever you want.

It speaks your callers' language​

The recorded greeting comes in 16 languages: English, Arabic, Chinese (Mandarin), Dutch, French, German, Hebrew, Hindi, Italian, Japanese, Korean, Polish, Portuguese (Brazil), Russian, Spanish and Turkish. After that, the agent talks in whatever language you write its instructions in, and if a caller speaks another language, it switches to theirs. I tried it in (my very horrible) Arabic and it held up nicely.

One tip: the sample opening line and rules start out in English, so translate them (or clear them) first. Quality can vary by language, so once your number is connected, give it a few test calls in your language before you share the number.

Why rules, and not a flowchart​

If you've used our phone system you know I love a good grid - modules, cables, the whole thing. A lot of AI voice tools go that way too, with boxes and connectors you drag around.

We didn't. An AI agent understands plain language, so why not just tell it what to do? Each rule is a sentence plus an action: Just answer, Take a message, Transfer to… or End the call. "When the caller asks for the owner, transfer them to my cell." That's a rule. The agent follows whichever rule fits what the caller said, so there's no order to worry about.

We found it's cleaner, easier and a lot faster to set up. You still get something to look at though - the How a call goes panel next to your rules (the screenshot up top) shows the whole call as you type. If you'd rather have boxes and cables, tell me. I'm not married to it (though I do love a grid).

Setting it up​

Open AI Voice Agents in the panel sidebar and create an agent.

Tell it who it answers calls for and how it should behave. Then give it what it needs to know - hours, prices, directions, or for a personal line, when you're free and how to reach you. It sticks to what you give it, no making things up.

The Agent tab of an AI voice agent named Sam's personal line: agent name, 'Who does the agent answer calls for?' filled in as Sam, a freelance photographer, the voice, a Greeting language dropdown set to English with the greeting callers will hear shown below it, and a short description of how the agent should behave.

Add your rules, hit Publish, and if your account is approved it's live right away (if not, it goes live on its own once it is). Last step: open your number, choose AI voice agent answers under Call handling, and pick your agent.

A FlyNumber's Call Handling settings with AI voice agent answers selected, the bike repair shop agent picked in the Agent dropdown, and a banner reading AI voice agent answers: Sunset Bike Repair.

When someone leaves a message you get an email and a panel notification. Every call shows up in the agent's history with the full transcript.

The Recent calls table for an agent with the newest call expanded: its transcript as chat bubbles (the agent greets the caller, the caller asks about opening hours, the agent answers, the caller says that's all, the agent says goodbye) and the tool used, end call. Below it, four more calls with their time, caller, number, length, result and charge.

Pricing​

$0.10 per minute of AI conversation, billed per second. No monthly fee for the agent; numbers, metered inbound, transfers and SMS are billed as usual.

That's it - no AI platform account, no per-seat fee. A two-minute call is 20 cents. You set a monthly ceiling ($5 to $500, $50 by default), and once you hit it callers go to your fallback instead. Publishing needs a $10 balance.

It's a beta​

There's one voice for now, AI conversations end at 5 minutes, and each account gets two AI calls at once and up to 10 agents. It answers calls, it doesn't make them. You get a transcript, not a recording, and transcripts, messages and caller numbers are deleted after 90 days.

Already sending calls to VAPI, ElevenLabs or another platform? That still works exactly the same.

Go set one up and tell me what you think.