Vapi

Vapi - AI Voice Assistant Builder

Build AI-powered voice assistants, phone agents, and conversational AI applications with Vapi.

When This Skill is Activated

When a user wants to build a voice assistant or phone agent, follow these steps:

Step 1: Check if Vapi MCP is Installed

First, check if the Vapi MCP server is available by looking for vapi_ tools. If not available, tell the user to run:

claude mcp add vapi -- npx -y @vapi-ai/mcp-server

Then restart Claude Code and continue with Step 2.

Step 2: Authenticate with Vapi

If the user hasn't authenticated yet (tools return auth errors):

1. Call vapi_login to start the OAuth flow
2. Tell the user to open the provided URL and sign in
3. Once authenticated, proceed with their request

Step 3: Build the Voice Assistant

Before creating an assistant, fetch the latest prompt engineering guidelines from the Prompt Guide.

Use these guidelines to craft effective voice assistant prompts based on what the user wants to build.

Available Tools

Authentication

• vapi_login - Start OAuth authentication flow
• vapi_logout - Log out and clear stored credentials

Assistants

• vapi_list_assistants - List all assistants
• vapi_get_assistant - Get assistant details
• vapi_create_assistant - Create new assistant
• vapi_update_assistant - Update assistant
• vapi_delete_assistant - Delete assistant

Calls

• vapi_list_calls - List call history
• vapi_get_call - Get call details
• vapi_create_call - Start outbound call

Phone Numbers

• vapi_list_phone_numbers - List phone numbers
• vapi_buy_phone_number - Purchase new number
• vapi_update_phone_number - Update number settings
• vapi_delete_phone_number - Release number

Tools (Function Calling)

• vapi_list_tools - List custom tools
• vapi_create_tool - Create tool for API integration
• vapi_update_tool - Update tool
• vapi_delete_tool - Delete tool

Workflow Examples

User: "I want to build a voice assistant that can schedule appointments"

Claude should:

1. Check for Vapi MCP -> install if needed
2. Authenticate if needed
3. Fetch the prompt guide for best practices
4. Ask about their business to understand context
5. Create an assistant with a scheduling-focused prompt
6. Offer to set up a phone number
7. Help create calendar integration tools if needed

User: "Make me a phone bot that answers questions about my business"

Claude should:

1. Ensure Vapi MCP is installed and authenticated
2. Fetch the prompt guide for best practices
3. Ask about the business: name, services, hours, common questions
4. Craft a system prompt following the guidelines
5. Create the assistant
6. Help provision or connect a phone number
7. Offer to test with a sample call

Source: VapiAI/mcp-server — distributed by TomeVault.