Vapi MCP Server

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

Claude Desktop Setup

1. Open Claude Desktop and press CMD + , to go to Settings.

2. Click on the Developer tab.

3. Click on the Edit Config button.

4. This will open the claude_desktop_config.json file in your file explorer.

5. Get your Vapi API key from the Vapi dashboard (https://dashboard.vapi.ai/org/api-keys).

6. Add the following to your claude_desktop_config.json file. See here for more details.

7. Restart the Claude Desktop after editing the config file.

Local Configuration

Remote Configuration

Example Usage with Claude Desktop

1. Create or import a phone number using the Vapi dashboard (https://dashboard.vapi.ai/phone-numbers).

2. Create a new assistant using the existing 'Appointment Scheduler' template in the Vapi dashboard (https://dashboard.vapi.ai/assistants).

3. Make sure to configure Claude Desktop to use the Vapi MCP server and restart the Claude Desktop app.

4. Ask Claude to initiate or schedule a call. See examples below:

Example 1: Request an immediate call

Example 2: Schedule a future call

Example 3: Make a call with dynamic variables

Related MCP server: MCP Server

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

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

Update your claude_desktop_config.json to use the local server.

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.

End-to-End Tests

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

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

Running All Tests

To run all tests at once:

References

• VAPI Remote MCP Server

• VAPI MCP Tool

• VAPI MCP Server SDK

• Model Context Protocol

• Claude Desktop

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