Function Calling Overview

After implementing basic conversations, your agent needs additional capabilities to perform actions such as:

1. Transferring calls
2. Booking appointments
3. Retrieving external information (e.g., weather data)
4. Managing call flow (e.g., ending calls)
5. Integrating with your existing systems via API calls

These capabilities can be implemented using function calling.

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Understanding Function Calling

Function calling (also known as tool calling) allows your voice agent to perform actions by:

• Calling external APIs
• Executing specific functions in your system
• Managing call flow operations

The LLM intelligently decides when to call these functions by outputting structured JSON objects containing the necessary arguments.

For a detailed understanding, we recommend:

• OpenAI’s Function Calling Guide
• Function Calling Tutorial

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Configuring Tool Calls

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Dashboard Configuration

Access and manage tools in the agent detail page under the “Functions” section.

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Tool Types

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1. Pre-defined Tools

• Built-in tools available to all users
• Configurable triggers and parameters
• This includes tools to:
  • End the call
  • Transfer the call
  • Press digits
  • Check availability
  • Book calendar

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2. Custom Tools

• User-defined functions with custom signatures
• Configurable speech behavior during and after execution
• Support for background execution
• Learn more about custom tools

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Video Tutorial

See community templates in docs