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

# Create Call

> Make an outbound phone call from your AI agent.

Initiates a real phone call from the AI agent's phone number to the
specified destination. The agent uses its configured system prompt,
voice, and greeting to conduct the conversation autonomously.

The AI agent handles the entire call — speech-to-text, LLM reasoning,
and text-to-speech — in real time. The call transcript is saved
automatically and can be retrieved via GET /v1/calls/{call_id}/transcript.

Request body:
  - agent_id: the AI agent making the call
  - to_number: destination phone number in E.164 format (e.g. "+12125551234")
  - from_number_id: (optional) specific number to call from
  - system_prompt: (optional) override the agent's default prompt for this call
  - initial_greeting: (optional) override the agent's greeting for this call
  - voice_id: (optional) override the voice for this call



## OpenAPI

````yaml /openapi.json post /v1/calls
openapi: 3.1.0
info:
  title: AgentLine
  description: >-
    AgentLine gives every AI agent a real phone number, a human-like voice, and
    the ability to make and receive calls and SMS autonomously. This SDK covers
    the core developer surface: agents, numbers, calls, messages, events,
    webhooks, billing, and voice.
  version: 0.3.0
  summary: Phone numbers, voice, and SMS for AI agents.
  contact:
    name: AgentLine
    url: https://agentline.cloud
  license:
    name: MIT
    url: https://opensource.org/license/mit
servers:
  - url: https://api.agentline.cloud
    description: Production
security:
  - API Key or OAuth: []
paths:
  /v1/calls:
    post:
      tags:
        - Calls
      summary: Create Call
      description: >-
        Make an outbound phone call from your AI agent.


        Initiates a real phone call from the AI agent's phone number to the

        specified destination. The agent uses its configured system prompt,

        voice, and greeting to conduct the conversation autonomously.


        The AI agent handles the entire call — speech-to-text, LLM reasoning,

        and text-to-speech — in real time. The call transcript is saved

        automatically and can be retrieved via GET
        /v1/calls/{call_id}/transcript.


        Request body:
          - agent_id: the AI agent making the call
          - to_number: destination phone number in E.164 format (e.g. "+12125551234")
          - from_number_id: (optional) specific number to call from
          - system_prompt: (optional) override the agent's default prompt for this call
          - initial_greeting: (optional) override the agent's greeting for this call
          - voice_id: (optional) override the voice for this call
      operationId: make_outbound_call
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/CallRequest'
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema: {}
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/HTTPValidationError'
      security:
        - API Key or OAuth: []
components:
  schemas:
    CallRequest:
      properties:
        agent_id:
          type: string
          title: Agent Id
          description: ID of the AI agent making the call (e.g. 'agt_abc123')
        to_number:
          type: string
          title: To Number
          description: Destination phone number in E.164 format (e.g. '+12125551234')
        system_prompt:
          anyOf:
            - type: string
            - type: 'null'
          title: System Prompt
          description: >-
            Per-call system prompt override. Replaces the agent's default prompt
            for this call ONLY. If omitted, the agent's default system_prompt is
            used.
        initial_greeting:
          anyOf:
            - type: string
            - type: 'null'
          title: Initial Greeting
          description: >-
            Per-call greeting override. Replaces the agent's default greeting
            for this call ONLY. If omitted, the agent's default initial_greeting
            is used.
        voice_id:
          anyOf:
            - type: string
            - type: 'null'
          title: Voice Id
          description: >-
            Override the TTS voice for this call: preset name (e.g. 'female-1')
            or Cartesia UUID
        from_number_id:
          anyOf:
            - type: string
            - type: 'null'
          title: From Number Id
          description: >-
            Specific phone number ID to call from; defaults to the agent's
            assigned number
      type: object
      required:
        - agent_id
        - to_number
      title: CallRequest
    HTTPValidationError:
      properties:
        detail:
          items:
            $ref: '#/components/schemas/ValidationError'
          type: array
          title: Detail
      type: object
      title: HTTPValidationError
    ValidationError:
      properties:
        loc:
          items:
            anyOf:
              - type: string
              - type: integer
          type: array
          title: Location
        msg:
          type: string
          title: Message
        type:
          type: string
          title: Error Type
        input:
          title: Input
        ctx:
          type: object
          title: Context
      type: object
      required:
        - loc
        - msg
        - type
      title: ValidationError
  securitySchemes:
    API Key or OAuth:
      type: http
      description: >-
        AgentLine API key. Get one via the email OTP flow (POST /v1/auth/otp
        then POST /v1/auth/verify). Pass as: Authorization: Bearer sk_live_...
      scheme: bearer
      bearerFormat: API key (sk_live_...)
      x-fern-bearer:
        name: apiKey
        env: AGENTLINE_API_KEY

````