> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tetherai.ca/llms.txt
> Use this file to discover all available pages before exploring further.

# ElevenLabs tool: send an SMS to the caller mid-call

> Server tool webhook called by the ElevenLabs voice agent mid-call to text the caller a link, confirmation, or follow-up info while the call is still active. Identifies the contact by `phone_number` within the org scoped from the tool secret, finds or creates the appropriate SMS conversation, and dispatches through the standard `sendOutboundMessage` helper so it routes via the org's configured SMS provider (Sinch / TextGrid / Twilio) and appears in the conversation thread as an AI-authored message. The send is marked `skipAutomation` so it doesn't retrigger workflows in a loop. Recoverable problems return HTTP 200 with `success:false`. Authenticated via Bearer token (per-org `elevenlabsToolSecret`).



## OpenAPI

````yaml /api-reference/openapi.yaml post /api/webhook/elevenlabs/tools/send-sms
openapi: 3.0.3
info:
  title: Tether Relay and Tether API
  version: 1.0.0
  description: >-
    Route-derived OpenAPI contract generated from tether-relay backend sources.
    Regenerate with scripts/sync-openapi-from-backend.mjs.
servers:
  - url: https://your-instance.example.com
    description: Production
  - url: http://localhost:2212
    description: Local API service
security: []
tags:
  - name: AI
  - name: Applications
  - name: Approval
  - name: Auth
  - name: Automations
  - name: Calls
  - name: Campaigns
  - name: Contact Analytics
  - name: Contact Metrics
  - name: Contact Notes
  - name: Contacts
  - name: Conversation Monitor
  - name: Conversations
  - name: Departments
  - name: Email
  - name: Escalation Dashboard
  - name: Event Logs
  - name: Google Sheets
  - name: Marketplace
  - name: Messages
  - name: Notification Sounds
  - name: Notifications
  - name: Org Snapshots
  - name: Organizations
  - name: Outreach
  - name: Outreach Metrics
  - name: Outreach Sources
  - name: Pipelines
  - name: Processes
  - name: Prompts
  - name: Reminders
  - name: Sms
  - name: Templates
  - name: Traces
  - name: Training
  - name: Upload
  - name: User Snapshots
  - name: Users
  - name: Vertical
  - name: Webchats
  - name: Webhook
paths:
  /api/webhook/elevenlabs/tools/send-sms:
    post:
      tags:
        - Webhooks
      summary: 'ElevenLabs tool: send an SMS to the caller mid-call'
      description: >-
        Server tool webhook called by the ElevenLabs voice agent mid-call to
        text the caller a link, confirmation, or follow-up info while the call
        is still active. Identifies the contact by `phone_number` within the org
        scoped from the tool secret, finds or creates the appropriate SMS
        conversation, and dispatches through the standard `sendOutboundMessage`
        helper so it routes via the org's configured SMS provider (Sinch /
        TextGrid / Twilio) and appears in the conversation thread as an
        AI-authored message. The send is marked `skipAutomation` so it doesn't
        retrigger workflows in a loop. Recoverable problems return HTTP 200 with
        `success:false`. Authenticated via Bearer token (per-org
        `elevenlabsToolSecret`).
      operationId: post_webhook_elevenlabs_tools_send_sms
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ElevenLabsSendSmsRequest'
      responses:
        '200':
          description: SMS send result. Inspect `success`.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ElevenLabsSendSmsResponse'
        '401':
          description: Unauthorized — missing or invalid tool secret
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/WebhookErrorResponse'
        '500':
          description: Internal server error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/WebhookErrorResponse'
components:
  schemas:
    ElevenLabsSendSmsRequest:
      type: object
      description: >-
        ElevenLabs send-sms tool args. `phone_number` identifies the contact
        within the org.
      properties:
        phone_number:
          type: string
        message:
          type: string
          description: >-
            SMS body. Trimmed; the SMS is marked AI-authored and
            `skipAutomation`.
        called_id:
          type: string
        called_number:
          type: string
      required:
        - phone_number
        - message
      additionalProperties: true
      example:
        phone_number: '+14165550100'
        message: >-
          Hi Alex — here's the application link we just talked about:
          https://app.tetherai.ca/a/MZ4K. Let me know if you have any trouble.
        called_id: '+12362320246'
    ElevenLabsSendSmsResponse:
      type: object
      properties:
        success:
          type: boolean
        message:
          type: string
        error:
          type: string
      required:
        - success
      additionalProperties: true
      example:
        success: true
        message: SMS sent
    WebhookErrorResponse:
      type: object
      description: >-
        Error envelope used across provider webhook routes. Most failures only
        carry `error`; a few (ElevenLabs tool errors, ingress validation) add
        `success:false`, `message`, or a `code`. Many of these endpoints respond
        200 with `success:false` for recoverable cases (especially the
        ElevenLabs server tools) — only hard failures use 4xx/5xx.
      properties:
        error:
          type: string
        message:
          type: string
        success:
          type: boolean
          enum:
            - false
        code:
          type: string
        details:
          description: Optional diagnostic detail (stack snippet, validation issues, etc.).
      additionalProperties: true
      example:
        error: Webhook processing failed

````