Vapi MCP Server

The Vapi Model Context Protocol server allows you to integrate with Vapi APIs through function calling.

Claude Desktop Setup

Open Claude Desktop and press CMD + , to go to Settings.
Click on the Developer tab.
Click on the Edit Config button.
This will open the claude_desktop_config.json file in your file explorer.
Get your Vapi API key from the Vapi dashboard (https://dashboard.vapi.ai/org/api-keys).
Add the following to your claude_desktop_config.json file. See here for more details.
Restart the Claude Desktop after editing the config file.

Local Configuration

{
  "mcpServers": {
    "vapi-mcp-server": {
      "command": "npx",
      "args": [
          "-y",
          "@vapi-ai/mcp-server"
      ],
      "env": {
        "VAPI_TOKEN": "<your_vapi_token>"
      }
    }
  }
}

Remote Configuration

{
  "mcpServers": {
    "vapi-mcp": {
      "command": "npx",
      "args": [
        "mcp-remote",
        "https://mcp.vapi.ai/mcp",
        "--header",
        "Authorization: Bearer ${VAPI_TOKEN}"
      ],
      "env": {
        "VAPI_TOKEN": "<your_vapi_token>"
      }
    }
  }
}

Example Usage with Claude Desktop

Create or import a phone number using the Vapi dashboard (https://dashboard.vapi.ai/phone-numbers).
Create a new assistant using the existing 'Appointment Scheduler' template in the Vapi dashboard (https://dashboard.vapi.ai/assistants).
Make sure to configure Claude Desktop to use the Vapi MCP server and restart the Claude Desktop app.
Ask Claude to initiate or schedule a call. See examples below:

Example 1: Request an immediate call

I'd like to speak with my ShopHelper assistant to talk about my recent order. Can you have it call me at +1234567890?

Example 2: Schedule a future call

I need to schedule a call with Mary assistant for next Tuesday at 3:00 PM. My phone number is +1555123456.

Example 3: Make a call with dynamic variables

I want to call +1234567890 with my appointment reminder assistant. Use these details:
- Customer name: Sarah Johnson
- Appointment date: March 25th
- Appointment time: 2:30 PM
- Doctor name: Dr. Smith

Using Variable Values in Assistant Prompts

The create_call action supports passing dynamic variables through assistantOverrides.variableValues. These variables can be used in your assistant's prompts using double curly braces: {{variableName}}.

Example Assistant Prompt with Variables

Hello {{customerName}}, this is a reminder about your appointment on {{appointmentDate}} at {{appointmentTime}} with {{doctorName}}.

Default Variables

The following variables are automatically available (no need to pass in variableValues):

{{now}} - Current date and time (UTC)
{{date}} - Current date (UTC)
{{time}} - Current time (UTC)
{{month}} - Current month (UTC)
{{day}} - Current day of month (UTC)
{{year}} - Current year (UTC)
{{customer.number}} - Customer's phone number

For more details on default variables and advanced date/time formatting, see the official Vapi documentation.

Remote MCP

To connect to Vapi's MCP server remotely:

Streamable HTTP (Recommended)

The default and recommended way to connect is via Streamable HTTP Transport:

Connect to https://mcp.vapi.ai/mcp from any MCP client using Streamable HTTP Transport
Include your Vapi API key as a bearer token in the request headers
Example header: Authorization: Bearer your_vapi_api_key_here

SSE (Deprecated)

Server-Sent Events (SSE) Transport is still supported but deprecated:

Connect to https://mcp.vapi.ai/sse from any MCP client using SSE Transport
Include your Vapi API key as a bearer token in the request headers
Example header: Authorization: Bearer your_vapi_api_key_here

This connection allows you to access Vapi's functionality remotely without running a local server.

Development

# Install dependencies
npm install

# Build the server
npm run build

# Use inspector to test the server
npm run inspector

Update your claude_desktop_config.json to use the local server.

{
  "mcpServers": {
    "vapi-local": {
      "command": "node",
      "args": [
        "<path_to_vapi_mcp_server>/dist/index.js"
      ],
      "env": {
        "VAPI_TOKEN": "<your_vapi_token>"
      }
    },
  }
}

Testing

The project has two types of tests:

Unit Tests

Unit tests use mocks to test the MCP server without making actual API calls to Vapi.

# Run unit tests
npm run test:unit

End-to-End Tests

E2E tests run the full MCP server with actual API calls to Vapi.

# Set your Vapi API token
export VAPI_TOKEN=your_token_here

# Run E2E tests
npm run test:e2e

Note: E2E tests require a valid Vapi API token to be set in the environment.

Running All Tests

To run all tests at once:

npm test

Supported Actions

The Vapi MCP Server provides the following tools for integration:

Assistant Tools

list_assistants: Lists all Vapi assistants
create_assistant: Creates a new Vapi assistant
update_assistant: Updates an existing Vapi assistant
get_assistant: Gets a Vapi assistant by ID

Call Tools

list_calls: Lists all Vapi calls
create_call: Creates an outbound call with support for:
- Immediate or scheduled calls
- Dynamic variable values through assistantOverrides
get_call: Gets details of a specific call

Note: The create_call action supports scheduling calls for immediate execution or for a future time. You can also pass dynamic variables using assistantOverrides.variableValues to personalize assistant messages.

Phone Number Tools

list_phone_numbers: Lists all Vapi phone numbers
get_phone_number: Gets details of a specific phone number

Vapi Tools

list_tools: Lists all Vapi tools
get_tool: Gets details of a specific tool