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 ().
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.

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

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

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1. Create or import a phone number using the Vapi dashboard ().
2. Create a new assistant using the existing 'Appointment Scheduler' template in the Vapi dashboard ().
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

`md
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

`md
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

`md
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}}.

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

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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:

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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

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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

`bash


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.

`json
{
"mcpServers": {
"vapi-local": {
"command": "node",
"args": [
"/dist/index.js"
],
"env": {
"VAPI_TOKEN": ""
}
},
}
}
`

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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.

`bash


Run unit tests


npm run test:unit
`

#### End-to-End Tests

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

`bash


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:

`bash
npm test
`

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:

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- 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

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- 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.

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

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