> ## 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 Agent > Create a new AI voice agent for telephony. Sets up a new AI phone agent with a custom system prompt, voice, and greeting. Once created, buy a phone number and attach it to this agent so it can make and receive calls autonomously. Fields: - name: Display name for the agent - system_prompt: Instructions that define the agent's personality and behavior on calls - initial_greeting: What the AI agent says when the call connects - voice_id: TTS voice preset (e.g. "female-1") or Cartesia UUID - transfer_number: Phone number to transfer calls to (e.g. a human operator) - voicemail_message: Message the agent leaves if the call goes to voicemail ## OpenAPI ````yaml /openapi.json post /v1/agents 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/agents: post: tags: - Agents summary: Create Agent description: |- Create a new AI voice agent for telephony. Sets up a new AI phone agent with a custom system prompt, voice, and greeting. Once created, buy a phone number and attach it to this agent so it can make and receive calls autonomously. Fields: - name: Display name for the agent - system_prompt: Instructions that define the agent's personality and behavior on calls - initial_greeting: What the AI agent says when the call connects - voice_id: TTS voice preset (e.g. "female-1") or Cartesia UUID - transfer_number: Phone number to transfer calls to (e.g. a human operator) - voicemail_message: Message the agent leaves if the call goes to voicemail operationId: create_agent requestBody: content: application/json: schema: $ref: '#/components/schemas/AgentCreate' required: true responses: '200': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/AgentOut' '422': description: Validation Error content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' security: - API Key or OAuth: [] components: schemas: AgentCreate: properties: name: type: string title: Name description: Display name for the AI voice agent system_prompt: anyOf: - type: string - type: 'null' title: System Prompt description: >- Default instructions for the agent's personality and behavior on ALL calls (inbound and outbound). Can be overridden per-call via POST /v1/calls. initial_greeting: anyOf: - type: string - type: 'null' title: Initial Greeting description: >- Default opening line spoken on ALL calls (inbound and outbound), e.g. 'Hello, how can I help you today?'. Can be overridden per-call via POST /v1/calls. voice_id: anyOf: - type: string - type: 'null' title: Voice Id description: >- TTS voice preset name (e.g. 'female-1', 'male-1') or Cartesia voice UUID; defaults to system voice if not set transfer_number: anyOf: - type: string - type: 'null' title: Transfer Number description: >- Phone number in E.164 format to transfer calls to (e.g. a human operator fallback) voicemail_message: anyOf: - type: string - type: 'null' title: Voicemail Message description: Message the AI agent leaves if the call goes to voicemail owner_phone: anyOf: - type: string - type: 'null' title: Owner Phone description: >- Owner's phone number in E.164 format (e.g. '+12125551234'). Calls from this number enter task mode — the agent treats speech as executable instructions. additionalProperties: false type: object required: - name title: AgentCreate AgentOut: properties: id: type: string title: Id description: Unique agent identifier (e.g. 'agt_abc123') account_id: type: string title: Account Id description: Account that owns this agent name: type: string title: Name description: Display name of the AI voice agent system_prompt: anyOf: - type: string - type: 'null' title: System Prompt description: Default system prompt for all calls (can be overridden per-call) initial_greeting: anyOf: - type: string - type: 'null' title: Initial Greeting description: Default greeting for all calls (can be overridden per-call) voice_id: anyOf: - type: string - type: 'null' title: Voice Id description: TTS voice preset or Cartesia UUID transfer_number: anyOf: - type: string - type: 'null' title: Transfer Number description: Phone number for call transfers voicemail_message: anyOf: - type: string - type: 'null' title: Voicemail Message description: Message left on voicemail owner_phone: anyOf: - type: string - type: 'null' title: Owner Phone description: Owner's phone number for task mode created_at: type: string format: date-time title: Created At description: When the agent was created type: object required: - id - account_id - name - created_at title: AgentOut 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 ````