For AI agents: a documentation index is available at the root level at /llms.txt and /llms-full.txt. Append /llms.txt to any URL for a page-level index, or .md for the markdown version of any page.
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DocumentationAPI ReferenceMCPSDKsCLI (new)What's New?
DocumentationAPI ReferenceMCPSDKsCLI (new)What's New?
  • Get started
    • Introduction
    • Phone calls
    • Web calls
    • Vapi Guides
    • Composer
    • CLI quickstart
  • Assistants
    • Quickstart
    • Tools
      • Built-in call tools
      • Voicemail tool
      • Custom tools
      • Code tool
      • Client-side tools (Web SDK)
      • Tool rejection plan
      • Static variables and aliases
      • Custom tools troubleshooting
      • Handoff tool
      • Knowledge retrieval
      • Argument encryption
    • Custom keywords
    • Custom voices
    • Custom transcriber
    • Custom TTS
  • Observability
    • Boards
  • Squads
    • Quickstart
    • Overview
    • Handoff tool
    • Passing data between assistants
  • Best practices
    • Prompting guide
    • Debugging voice agents
    • Enterprise environments (DEV/UAT/PROD)
    • IVR navigation
  • Phone numbers
    • Free Vapi number
    • Inbound SMS
    • Phone Number Hooks
  • Calls
    • Call end reasons
    • Troubleshoot call errors
  • Outbound Campaigns
    • Quickstart
    • Overview
  • Chat
    • Quickstart
    • Streaming
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    • OpenAI compatibility
    • Session management
    • Variable substitution
    • SMS chat
    • Web widget
    • Webhooks
  • Workflows
    • Quickstart
    • Overview
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On this page
  • Available Tools
  • Integration Tools
  • Key Features
  • Learn More
Assistants

Introduction to Tools

Extend your assistant's capabilities with powerful function calling tools.
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Default Tools

Adding Transfer Call, End Call, Dial Keypad, and API Request capabilities to your assistants.
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Built with

Tools allow your assistant to take actions beyond just conversation. They enable your assistant to perform tasks like transferring calls, accessing external data, or triggering actions in your application. Tools can be either built-in default tools provided by Vapi or custom tools that you create.

There are four types of tools available:

  1. Default Tools: Built-in functions provided by Vapi for common operations like call transfers and control.
  2. Custom Tools: Your own functions that can be called by the assistant to interact with your systems via webhooks.
  3. Code Tools: Write TypeScript code that executes directly on Vapi’s infrastructure without setting up a server.
  4. Integration Tools: Pre-built integrations with platforms like Make and GoHighLevel (GHL) that let you trigger automated workflows via voice.

Tools are configured as part of your assistant’s model configuration. You can find the complete API reference here.

Available Tools

Default Tools

Built-in tools for call control, transfers, and basic operations

Custom Tools

Create your own webhook-based tools to extend assistant capabilities

Code Tools

Write TypeScript code that runs directly without a server

Make & GHL Tools

Import Make scenarios and GHL workflows as voice-activated tools

Integration Tools

With Make and GHL integrations, you can:

  • Import existing Make scenarios and GHL workflows directly into Vapi
  • Trigger automated workflows using voice commands
  • Connect your voice AI to hundreds of apps and services
  • Automate complex business processes through voice interaction

Common use cases include:

  • Booking appointments via voice
  • Updating CRM records during calls
  • Triggering email or SMS follow-ups
  • Processing orders and payments
  • Managing customer support tickets

Key Features

Function Calling

Assistants can trigger functions based on conversation context

Async Support

Tools can run synchronously or asynchronously

Server Integration

Connect tools to your backend via webhooks

Error Handling

Built-in error handling and fallback options

Learn More

Make & GHL Integration Guide

Learn how to import and use Make scenarios and GHL workflows as voice-activated tools

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