> ## Documentation Index
> Fetch the complete documentation index at: https://documentation.uponai.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Function Calling Overview

> Enable your AI agent to perform actions like transfers, bookings, and API integrations through function calling.

## Introduction

Function calling transforms your AI agent from a conversational interface into an action-oriented assistant. By connecting your agent to functions, you enable it to interact with external systems, manage call flows, and perform real-world tasks.

***

## Common Use Cases

### Call Management

* **Transfer calls**: Route to human agents or other departments
* **End calls**: Gracefully terminate conversations
* **Send DTMF tones**: Navigate phone menus

### Business Operations

* Schedule and book appointments
* Check availability across systems
* Create, modify, or cancel orders

### Data Integration

* Retrieve information from external systems
* Update customer records and case details
* Trigger notifications via email, SMS, or push

***

## How Function Calling Works

<Steps>
  <Step title="LLM detects need">
    Based on conversation context, the LLM determines when a function is needed.
  </Step>

  <Step title="Parameters extracted">
    The agent pulls the required values from the conversation.
  </Step>

  <Step title="Function executes">
    UponAI runs the function against the configured endpoint or built-in tool.
  </Step>

  <Step title="Result integrated">
    The response feeds back into the ongoing conversation.
  </Step>
</Steps>

***

## Available Function Types

<CardGroup cols={3}>
  <Card title="Pre-built Functions" icon="bolt">
    Six ready-to-use options: End Call, Transfer Call, Press Digits, Check Availability, Book Calendar, and Send SMS.
  </Card>

  <Card title="Custom Functions" icon="code">
    Connect your own APIs, implement business logic, and trigger workflows in external systems.
  </Card>

  <Card title="Code Tool" icon="terminal">
    Execute JavaScript directly in UponAI's sandbox for data transformation, simple API calls, and calculations — no external server needed.
  </Card>
</CardGroup>

***

## Configuring Tool Calls

Add functions from the **Functions** section of your agent in the UponAI Dashboard. Each function type has its own configuration panel.

<Tip>
  Always update your agent's prompt to tell it explicitly when to call each function. Tool descriptions alone are not always enough for consistent behavior.
</Tip>