Skip to main content

SMS Agents

SMS agents send text messages to your contacts from their own phone numbers. Each agent can send an exact message you supply, or write one itself from context using its own instructions — triggered from a webhook, a LeadConnector workflow, or scheduled conversationally through Nox.

:::info Beta SMS agents are enabled per account — the number of SMS agents you can create is an allowance set by the Knock Knock team. If you don't see SMS Agents under Settings → AI Agents, contact support to have it enabled. :::

Setting up an SMS agent​

You can create multiple SMS agents, each with its own configuration. An agent's settings are organized into tabs:

  • AI Engine — the agent's instructions and prompt, which shape the tone and content of AI-composed messages.
  • Phone Numbers — the SMS-capable phone number the agent sends from. Buy a number directly in the app, or import one from your own Twilio account. An agent can't send until a number is connected.
  • Webhook — the agent's webhook secret, ready-made request examples, and a test panel (see below).
  • Scheduled — texts booked to send later (see below).
  • Message Log — every message the agent has sent, with delivery status.

Sending via webhook​

Each SMS agent has a webhook you can call from any external system, authenticated with the agent's own webhook secret — treat it like a password. There are two actions:

  • Send exact text (send_sms) — you supply the message and it's sent verbatim, no AI involved.
  • Let the agent write it (generate_sms) — you supply context as a JSON object, and the agent composes the message from those facts using its instructions and tone.

The Webhook tab includes a test panel for both actions, so you can fire a real test SMS to your own phone before wiring anything up.

Sending from LeadConnector workflows​

The LeadConnector marketplace app includes a Send SMS workflow action. Pick which of your SMS agents should send, and the message goes out from that agent's number as part of any workflow — no webhook plumbing required.

Scheduled texts​

The Scheduled tab lists texts booked for later — the agent sends them at the scheduled time. You can:

  • Filter by Upcoming, Sent, Failed, Cancelled, or All
  • See at a glance whether each text is AI-composed or plain text, and whether it was scheduled by Nox or manually
  • See quiet-hours deferrals, with a note explaining the text was moved to respect the contact's quiet hours
  • Cancel an upcoming text before it sends

You can also schedule a text right from the tab using the schedule form.

Scheduling through Nox​

Nox can schedule texts conversationally — "text him tomorrow at 9 about the quote" — in two modes:

  • Plain text — Nox schedules your exact words, sent verbatim.
  • AI-generated — the agent writes the text at send time from the context, using its instructions and tone.

Good to know​

  • Send-only for now. SMS agents send texts; inbound replies are not handled.
  • "Sent" means accepted by the carrier. A sent status confirms the carrier accepted the message, not that it was delivered to the handset.
  • Costs. SMS sent from app-purchased numbers is charged from your Wallet. Imported Twilio numbers are billed by Twilio directly.