Configure in-call SMS actions

Send SMS during calls lets a voice agent text the caller something useful while they're still on the phone, such as a booking link, an address, or a reference number. This guide is for whoever sets up the agent.

This is separate from Send Confirmation SMS in a calendar booking action. Turning on one doesn't turn on the other.

Before you begin

• A phone setup that can text. For US local numbers, finish A2P 10DLC registration and activate the number first.
• Credits. Each text uses credits. The cost per SMS is shown next to the switch.
• Consent. Have a clear process for getting permission and handling opt-outs for the people you'll text.
• Admin access. Only admins can turn the switch on or off. Others can view it.
• A test phone you own, with consent recorded.

Decide exactly what the agent may send. Never let it text passwords, one-time codes, card details, health or identity information, or links it hasn't been given.

Where to find it

Open Chat & Voice → Agents, open the agent, then select Actions in the sidebar. Send SMS during calls is below the Calendar booking section.

Turn it on

1. Find Send SMS during calls and read the per-SMS credit cost.
2. Turn on the switch. You'll see SMS setting updated for this agent.
3. Open the agent's Prompt and add clear instructions (see below).
4. Test it (see below) before real callers use it.

Spacebrain reuses your workspace's SMS action, or creates one if none exists, and links it to this agent. You don't need a calendar connection.

Turning the switch off unlinks the SMS action from this agent only. Other agents keep their own setting.

Write safe instructions

Tell the agent:

• When it may send: only when the caller asks for or agrees to a specific text.
• Where it sends: confirm the caller's current number is the right one.
• What it may include: only the approved link, address, or reference.
• How often: send once. Don't resend automatically if unsure.
• Stop requests: stop if the caller says no or opts out.
• Failures: if the text can't be confirmed, say so honestly and offer another option.

Example: "If the caller asks for our address or booking link, ask: 'Can I text that to the number you're calling from?' Only send after they say yes. Send the address or link and nothing else. Send it once. If sending fails, read the details out slowly instead."

The agent saying "I've sent it" isn't proof. Check the phone actually received it.

Test it

1. Call the agent from your test phone.
2. Ask for one simple, harmless text.
3. Check the agent confirms your number before sending.
4. Check the exact text arrives on the same phone.
5. Review the call recording or transcript, and your credit usage.
6. Try again: refuse the text, say STOP, ask for something it shouldn't send, and ask twice.
7. Confirm it handles each case properly and doesn't send more than once.

Repeat these tests whenever you change the agent's instructions, phone number, registration, or linked actions.

If something goes wrong

FAQ

Do I need to register for texting first?

To text US contacts from a local number, yes. See A2P 10DLC registration.

Can the agent text someone other than the caller?

It's designed to text the caller during the call. Instruct it to confirm the number and never send to a different one.

Next step

Set up the number your agent texts from: Phone numbers, Power Dialer, and outreach.