POST
/
api
/
project
/
{projectId}
/
integration
/
vapi
/
chat
/
completions
VAPI Integration
curl --request POST \
  --url https://app.pathors.com/api/project/{projectId}/integration/vapi/chat/completions \
  --header 'Content-Type: application/json' \
  --data '{
  "messages": [
    {}
  ],
  "stream": true,
  "tools": [
    {}
  ],
  "call": {},
  "phoneNumber": {},
  "customer": {}
}'
{
  "id": "<string>",
  "object": "<string>",
  "created": 123,
  "model": "<string>",
  "choices": [
    {}
  ],
  "choices[].message.tool_calls": [
    {}
  ],
  "choices[].finish_reason": "<string>",
  "session_id": "<string>"
}

​
VAPI Integration

The VAPI integration provides a chat completions endpoint specifically designed for handling phone call conversations through the Voice API service.

​
Chat Completions

POST /api/project/{projectId}/integration/vapi/chat/completions

​
Path Parameters

​
projectId
string
required
The ID of your project

​
Request Body

​
messages
array
required
Array of messages in the conversation. Each message should have a role (“system”, “user”, or “assistant”) and content.
​
stream
boolean
Whether to stream the response. Defaults to false.
​
tools
array
Array of external tool definitions that will be available for the assistant to use during the phone call. Each tool should have a type (currently only “function” is supported) and a function object with name, description, and parameters (JSON Schema format).
​
call
object
required
Information about the current call session.
{
  id: string;          // Call ID
  orgId: string;       // Organization ID
  createdAt: string;   // Call creation timestamp
  updatedAt: string;   // Call update timestamp
  type: string;        // Call type
  status: string;      // Call status
  assistantId: string; // Assistant ID
  customer?: {
    number: string;    // Customer phone number
  };
  phoneNumberId?: string;        // Phone number ID
  phoneCallProvider?: string;    // Call provider (e.g., Twilio)
  phoneCallProviderId?: string;  // Provider-specific call ID
  phoneCallTransport?: string;   // Call transport method
}
​
phoneNumber
object
Optional phone number configuration.
{
  id: string;              // Phone number ID
  orgId: string;           // Organization ID
  number: string;          // Phone number
  createdAt: string;       // Creation timestamp
  updatedAt: string;       // Update timestamp
  twilioAccountSid: string;// Twilio account SID
  twilioAuthToken: string; // Twilio auth token
  name: string;            // Phone number name
  provider: string;        // Phone provider
}
​
customer
object
Optional customer information.
{
  number: string;  // Customer phone number
}
Example request: 
{
  "messages": [
    {
      "role": "user",
      "content": "Hello!"
    }
  ],
  "stream": false,
  "call": {
    "id": "call_abc123",
    "orgId": "org_xyz789",
    "type": "inbound",
    "status": "in-progress",
    "assistantId": "asst_def456"
  }
}
Example request with tools: 
{
  "messages": [
    {
      "role": "user",
      "content": "Can you check my account status?"
    }
  ],
  "stream": false,
  "call": {
    "id": "call_abc123",
    "orgId": "org_xyz789",
    "type": "inbound",
    "status": "in-progress",
    "assistantId": "asst_def456",
    "customer": {
      "number": "+1234567890"
    }
  },
  "tools": [
    {
      "type": "function",
      "function": {
        "name": "check_account_status",
        "description": "Check customer account status and information",
        "parameters": {
          "type": "object",
          "properties": {
            "customer_phone": {
              "type": "string",
              "description": "Customer's phone number"
            }
          },
          "required": ["customer_phone"]
        }
      }
    }
  ]
}

​
Response

The response format is identical to the API integration’s chat completions endpoint, with the addition of session management for phone calls.
​
id
string
Unique identifier for the completion
​
object
string
Object type (“chat.completion”)
​
created
number
Unix timestamp of when the completion was created
​
model
string
Model used for the completion
​
choices
array
Array of completion choices
​
choices[].message.tool_calls
array
Array of tool calls made by the assistant (when tools are provided and used)
​
choices[].finish_reason
string
Reason for completion termination. Can be “stop” for normal completion or “tool_calls” when tools are invoked.
​
session_id
string
Session ID for the conversation
Example response: 
{
  "id": "chatcmpl-abc123",
  "object": "chat.completion",
  "created": 1677858242,
  "model": "pathway-default",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "Hi! How can I help you today?"
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": -1,
    "completion_tokens": -1,
    "total_tokens": -1
  },
  "session_id": "session-xyz789"
}
Example response with tool calls: 
{
  "id": "chatcmpl-abc123",
  "object": "chat.completion",
  "created": 1677858242,
  "model": "pathway-default",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "",
        "tool_calls": [
          {
            "id": "call_123",
            "type": "function",
            "function": {
              "name": "check_account_status",
              "arguments": "{\"customer_phone\": \"+1234567890\"}"
            }
          }
        ]
      },
      "finish_reason": "tool_calls"
    }
  ],
  "usage": {
    "prompt_tokens": -1,
    "completion_tokens": -1,
    "total_tokens": -1
  },
  "session_id": "session-xyz789"
}

​
Streaming Response

The streaming response format is identical to the API integration’s streaming format.

​
Error Responses

Status CodeDescription
400Invalid request body or missing call ID
500Internal server error

​
Working with Tools

When you provide tools in the VAPI request, the assistant can invoke them during the phone call conversation. The tool calling workflow is handled automatically:
  1. Tool Execution: When the assistant needs to call a tool, it will return a response with tool_calls
  2. Tool Results: You should execute the requested tools and send the results back in a follow-up request
  3. Final Response: The assistant will use the tool results to formulate its final response to the caller

​
Tool Message Format

After receiving tool calls, send the results back in your next request: 
{
  "messages": [
    {"role": "user", "content": "Can you check my account status?"},
    {
      "role": "assistant", 
      "content": "",
      "tool_calls": [
        {
          "id": "call_123",
          "type": "function", 
          "function": {
            "name": "check_account_status",
            "arguments": "{\"customer_phone\": \"+1234567890\"}"
          }
        }
      ]
    },
    {
      "role": "tool",
      "content": "Account status: Active, Balance: $150.00",
      "tool_call_id": "call_123",
      "name": "check_account_status"
    }
  ],
  "call": {
    "id": "call_abc123",
    "orgId": "org_xyz789",
    "type": "inbound",
    "status": "in-progress", 
    "assistantId": "asst_def456"
  }
}

​
Session Management

The VAPI integration uses the call ID as the session identifier for conversation continuity. Each unique call ID represents a separate conversation session.