Send Message Node

The agent confirms the appointment, reads out a reference number, and the caller writes it on the back of an envelope. Or they do not, and they ring back tomorrow to ask what it was.

A Send Message node texts them instead. Call, then text, is the pattern people in India actually complete — the conversation persuades, the message is the thing they keep.

Note

No new account. Twilio and Plivo bill messaging to the same account as voice, so the telephony configuration your agent already dials with can already send. WhatsApp needs a Twilio WhatsApp Business sender; everything else is already in place.

How it behaves

Like the Webhook node, this one is detached — no edges in or out. It is not a step in the conversation. It fires once the run completes, with everything the call gathered available to the message.

When	After the call ends, alongside webhooks and QA.
To	The number that was on the call, unless you say otherwise.
From	The configuration’s default caller ID, unless you say otherwise.
Body	Supports {{template_variables}} from the call.

Write the message

Namaste {{first_name}}, your appointment is confirmed for
{{appointment_time}}. Reference: {{reference_id}}

Everything the call knows is available: variables extracted during the conversation, columns from the campaign CSV, fields from the trigger payload, and anything a pre-call fetch returned.

Caution

Keep it short. Carriers split long messages into separately-billed segments — 160 characters for plain Latin text, but only 70 for Indic scripts, so a Telugu message hits the boundary in a sentence and a half. A 1,000-character message is not one message, it is fifteen. Anything past 1,600 characters is refused rather than sent, so the invoice never surprises you.

Only send when it is worth sending

The failure this node must not have is texting somebody a confirmation of a call that did not succeed. Only send if takes the same shape as a branch rule:

Variable	call_outcome
Condition	equals
Value	agreed

Leave the variable blank to always send.

Note

The same rule as a branch applies here, and for the same reason: a variable that is missing never matches. A call whose outcome you failed to capture is not a call that went well, so it is not texted a confirmation.

Reading what happened

Every attempt is recorded on the run under follow_up_messages:

{
  "follow_up_messages": [
    {
      "node": "Confirmation SMS",
      "ok": false,
      "provider": "twilio",
      "to": "+919876543210",
      "error": "The 'To' number is not a valid mobile number",
      "status_code": 400
    }
  ]
}

The carrier’s own words are kept, because “the To number is not a valid mobile number” tells you what to fix and “HTTP 400” does not.

Numbers

Recipients must be E.164 — +919876543210. Spaces, dashes and a leading 00 are cleaned up for you.

Caution

A bare ten-digit number is refused, not assumed. 9876543210 is a valid mobile in a dozen countries. Defaulting it to +91 would, for any customer dialling outside India, text a stranger about an appointment they never made — and the send would succeed, so nobody would find out.

Failures never take the call down with them

By the time this runs the conversation is over, the transcript is stored and the receipt is costed. A carrier that rate-limits you, a network blip, a number that turns out to be a landline — all of them are written onto the run and none of them stops the rest of the post-call work. Losing a call’s data over an SMS would be a bad trade.

From code

import { sms } from "@decibyl/sdk/typed";

await wf.addTyped(sms({
  name: "Confirmation SMS",
  channel: "sms",
  body: "Namaste {{first_name}}, ref {{reference_id}}.",
  send_when_variable: "call_outcome",
  send_when_operator: "equals",
  send_when_value: "agreed",
}));

No wf.edge call — the node is detached.

Next

• Branch Node — the same condition shape, for routing.
• Webhook — for telling your systems what happened.