The Send SMS tool gives your AI voice agent a way to text the person it's talking to — a booking link, a pricing page, an address — while the call is still live, instead of reading a URL out loud.
Who this is for
Anyone running AI phone calls in Alta who wants the agent to hand over a link or a short piece of text during the conversation.
Before you start
You need at least one phone number in Alta with the SMS capability (Settings → Phone Numbers). The tool can only send from an SMS-capable number.
You need an assistant that places phone calls. This tool does not work on chat assistants or on email replies — see the pitfalls below.
1. Create the tool
Go to Settings → Tools.
Click + Add a tool and choose Send SMS. Alta creates a tool named
Send SMSand opens it.Click the pencil icon next to the name to rename it. Name it after the one message it sends — for example
Text the booking link. You'll pick the tool by this name later.
2. Fill in the SMS Configuration card
When to send — required. Tell the agent the moment to use this tool, in plain language: "Send after the prospect agrees to receive the booking link." This is the only part of the tool the agent reasons about.
SMS content — required. The exact text that goes out. Write it as you want it read, and insert variables to personalize it — for example Hi + the First Name variable + , here is the link we discussed: https://... Alta validates the variables you insert.
Fallback sender number — optional, but strongly recommended. The message normally sends from the number that placed the call. Pick a number here to use instead when that number can't send texts. The dropdown only lists numbers that have the SMS capability; leave it on No fallback number to skip it.
3. Set what the agent says out loud (optional)
In the Spoken message card, use Message to control what the assistant says as it sends — for example "Let me check that for you, one moment…" Leave it empty and Alta uses a default phrase. Maximum 1,000 characters.
Click Save configuration. You'll see Tool updated successfully.
4. Attach it to an assistant
Open your calling assistant, or the Call touchpoint in your campaign.
Go to the Configurations tab.
In the Tools section, open Select Tools and pick your Send SMS tool.
Save the assistant.
Tips and common pitfalls
It only works on phone calls. Invoked anywhere else, the tool fails with
This tool can only be used during a phone call.It still appears in the tool picker for reply agents and chat assistants — it just can never run there.Test on a Phone Call, not a Web Call. A browser web call has no phone number attached, so there's no number for the SMS to go to.
The agent cannot change the message or the recipient. The text sent is exactly what you typed, and it always goes to the number Alta dialed. Anything that needs to vary per prospect has to be a variable.
Set a fallback if you call from a voice-only number. Alta tries the number that placed the call first, then your Fallback sender number — and each has to have the SMS capability. If neither qualifies, the tool fails mid-call with
No SMS-capable phone number is available to send this message.Empty variables render as nothing. Values come from the prospect record and from the call's own variables, with prospect fields taking priority. Write the message so it still reads correctly if a variable comes back blank.
These land in the Inbox. Mid-call texts are logged like any other SMS against that prospect, so the message — and any reply — shows up in the conversation.
Delivery failures reach the agent. If the carrier reports the message as failed or undelivered, the tool returns an error, so the assistant knows the send didn't work and can say so rather than assume.
One message per tool. The content is fixed. If you need to text three different things, create three Send SMS tools with distinct names and distinct When to send instructions.