Vapi MCP Server
Build AI voice assistants and phone agents with Vapi using the Model Context Protocol.
Setup
The MCP server requires a Vapi API key. Get one from the Vapi dashboard.
Local Server (stdio)
Configure any MCP client that supports local stdio servers to run:
npx -y @vapi-ai/mcp-server
Set VAPI_TOKEN in the server environment. MCP client configuration formats vary, but the server definition generally looks like this:
{
"mcpServers": {
"vapi": {
"command": "npx",
"args": ["-y", "@vapi-ai/mcp-server"],
"env": {
"VAPI_TOKEN": "<your_vapi_token>"
}
}
}
}
Remote Server (Streamable HTTP)
Clients that support remote MCP servers can connect directly:
- URL:
https://mcp.vapi.ai/mcp - Header:
Authorization: Bearer your_vapi_api_key_here
Client-Specific Examples
Claude Code
claude mcp add -e VAPI_TOKEN=your_vapi_token vapi -- npx -y @vapi-ai/mcp-server
Claude Desktop
Use the local server configuration above in the Claude Desktop configuration file. To connect to the hosted server through an stdio bridge instead:
{
"mcpServers": {
"vapi": {
"command": "npx",
"args": [
"mcp-remote",
"https://mcp.vapi.ai/mcp",
"--header",
"Authorization: Bearer ${VAPI_TOKEN}"
],
"env": {
"VAPI_TOKEN": "<your_vapi_token>"
}
}
}
}
Optional Agent Skill
The skill directory contains reusable instructions for AI coding agents that support Agent Skills. Install it using your host's skill installation process.
For Claude Code:
mkdir -p ~/.claude/skills/vapi
curl -o ~/.claude/skills/vapi/SKILL.md https://raw.githubusercontent.com/VapiAI/mcp-server/main/skill/SKILL.md
Example Usage
Create a Voice Assistant
Ask your MCP-enabled agent:
I want to build a voice assistant that can schedule appointments
Make an Outbound Call
Call +1234567890 using my appointment reminder assistant with these details:
- Customer name: Sarah Johnson
- Appointment date: March 25th
- Appointment time: 2:30 PM
Schedule a Future Call
Schedule a call with my support assistant for next Tuesday at 3:00 PM to +1555123456
Using Variable Values in Assistant Prompts
The create_call action supports passing dynamic variables through assistantOverrides.variableValues. Use double curly braces in your assistant's prompts: {{variableName}}.
Example Prompt with Variables
Hello {{customerName}}, this is a reminder about your appointment on {{appointmentDate}} at {{appointmentTime}} with {{doctorName}}.
Default Variables
These are automatically available (no need to pass):
{{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
See Vapi documentation for advanced date/time formatting.
Remote MCP Server
Connect to Vapi's hosted MCP server from any MCP client:
Streamable HTTP (Recommended)
- URL:
https://mcp.vapi.ai/mcp - Header:
Authorization: Bearer your_vapi_api_key_here
SSE (Deprecated)
- URL:
https://mcp.vapi.ai/sse - Header:
Authorization: Bearer your_vapi_api_key_here
Available Tools
Assistants
Calls
Phone Numbers
Tools (Function Calling)
Development
# Install dependencies
npm install
# Build
npm run build
# Test with MCP inspector
npm run inspector
Local Development Config
{
"mcpServers": {
"vapi-local": {
"command": "node",
"args": ["<path>/dist/index.js"],
"env": {
"VAPI_TOKEN": "<your_vapi_token>"
}
}
}
}
Testing
# Safe default suite (build, mocked execution, contract, and stdio compatibility)
npm test
# Unit tests (mocked public tool execution and catalog contract)
npm run test:unit
# Documentation/tool-catalog consistency lint
npm run test:docs
# Full TypeScript check (production and test code)
npm run typecheck
# Build and run local stdio protocol compatibility tests (no Vapi API calls)
npm run test:stdio
# Pack, install, and launch the package from a clean temporary consumer
npm run test:package
# Live read-only API tests
export VAPI_TOKEN=your_token_here
npm run test:live:readonly
# Live mutating tests (creates and cleans up disposable assistants and tools)
export VAPI_TOKEN=your_test_org_token_here
npm run test:live:mutating
