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Use Phone numbers as your shared number inventory. Settings → Channels → SMS turns an eligible number into a conversation channel. The same number can handle voice and SMS with different assistants.

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Set up your number

  1. Open Settings → Channels → SMS. Buy an SMS number or import an existing one through Phone numbers.
  2. Choose Set up SMS, name the channel and select an assistant.
  3. Save to connect incoming SMS. Automatic replies start off; enable Allow outbound SMS and AI auto-replies when ready.
  4. Set the response delay, inactivity timeout and optional conversation-ended webhook.
Platform numbers and imported Twilio BYOC numbers are supported when the number has SMS capability. A SIP trunk alone does not provide SMS. Some destinations require carrier registration; see SMS registration. For a BYOC Messaging Service, let incoming messages use the phone number’s webhook before connecting. Disabling the SMS channel preserves the number and voice routing. Removing or releasing the phone number disables its SMS channel.

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Replies and History

Open History, filter by SMS, and select a conversation. You can inspect messages, assistant actions, analysis, delivery status and charged credits, pause the assistant and reply manually. An unconfirmed delivery must be checked before retrying. Channel replies are plain text and must fit one SMS segment: up to 160 GSM-7 units, or 70 UTF-16 units when Unicode is needed. Some symbols count twice, and emojis usually use two Unicode units. The composer shows the limit. Assistant instructions enforce concise replies; long drafts get one rewrite and are never silently truncated. Attachments and RCS are not supported. SMS uses the existing SMS credit rate, including any applicable carrier component. There is no additional general chat-message charge. An estimated charge can change once the final carrier price arrives. Incoming STOP messages suppress further sending; restarting depends on the carrier’s supported opt-in flow.

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API, MCP and command line

Use POST /api/v1/messaging-connectors or MCP create_messaging_connector to connect the number. Use PATCH /api/v1/messaging-connectors/{id} or update_messaging_connector to enable, pause or configure it. List with GET /api/v1/messaging-connectors?platform=sms or list_messaging_connectors.
When importing a Twilio number, select Enable SMS conversations to continue directly to SMS setup. This is optional and does not turn on automatic replies.