ElevenLabs MCP Server

Instructions

Implementation Reference

• elevenlabs_mcp/server.py:1027-1054 (handler)

  The main handler function for the 'make_outbound_call' tool. It retrieves phone number details to detect the provider (Twilio or SIP trunk) and initiates the outbound call using the appropriate ElevenLabs API endpoint.
  def make_outbound_call( agent_id: str, agent_phone_number_id: str, to_number: str, ) -> TextContent: # Get phone number details to determine provider type phone_number = _get_phone_number_by_id(agent_phone_number_id) if phone_number.provider.lower() == "twilio": response = client.conversational_ai.twilio.outbound_call( agent_id=agent_id, agent_phone_number_id=agent_phone_number_id, to_number=to_number, ) provider_info = "Twilio" elif phone_number.provider.lower() == "sip_trunk": response = client.conversational_ai.sip_trunk.outbound_call( agent_id=agent_id, agent_phone_number_id=agent_phone_number_id, to_number=to_number, ) provider_info = "SIP trunk" else: make_error(f"Unsupported provider type: {phone_number.provider}") return TextContent( type="text", text=f"Outbound call initiated via {provider_info}: {response}." )
• elevenlabs_mcp/server.py:1013-1026 (registration)

  Registers the 'make_outbound_call' tool with the FastMCP server using the @mcp.tool decorator, including a detailed description of parameters and usage.
  @mcp.tool( description="""Make an outbound call using an ElevenLabs agent. Automatically detects provider type (Twilio or SIP trunk) and uses the appropriate API. ⚠️ COST WARNING: This tool makes an API call to ElevenLabs which may incur costs. Only use when explicitly requested by the user. Args: agent_id: The ID of the agent that will handle the call agent_phone_number_id: The ID of the phone number to use for the call to_number: The phone number to call (E.164 format: +1xxxxxxxxxx) Returns: TextContent containing information about the call """ )
• elevenlabs_mcp/server.py:1004-1011 (helper)

  Private helper function that fetches all phone numbers and returns the one matching the given ID, used by the handler to determine the provider type.
  def _get_phone_number_by_id(phone_number_id: str): """Helper function to get phone number details by ID.""" phone_numbers = client.conversational_ai.phone_numbers.list() for phone in phone_numbers: if phone.phone_number_id == phone_number_id: return phone make_error(f"Phone number with ID {phone_number_id} not found.")