Tools & Functions

While the System Prompt gives your assistant a brain and a voice, Tools give it hands. Tools allow the AI to perform actions during the call, such as checking a calendar, sending an SMS, or looking up customer data.

How Function Calling Works

Caller AI uses "Function Calling" (or Tool Use) logic. The flow works like this:

  1. Listening: The user says "I want to book an appointment for tomorrow."
  2. Reasoning: The AI analyzes the prompt and realizes it needs to check availability.
  3. Tool Selection: The AI triggers the `checkCalendar` tool.
  4. Execution: Caller AI runs the tool in the background (via API).
  5. Response: The AI receives the data (e.g., "Slots available: 2 PM, 4 PM") and speaks it to the user.

Built-in System Tools

Caller AI comes with several pre-configured tools that you can enable with a single click in the dashboard.

End Call
Function: `endCall`
Allows the AI to hang up the phone gracefully when the conversation is over.
Transfer Call
Function: `transferCall`
Forwards the current call to a specified phone number (e.g., human support tier).
Press Digits
Function: `pressDigits`
Allows the AI to navigate IVR menus (e.g., "Press 1 for Sales") if it calls another automated system.

Defining a Tool

When you add a tool, you must provide a Name and a Description. The Description is the most important part—it tells the AI when to use the tool.

Example Configuration Tool Name: CheckInventory
Description: Use this tool whenever the customer asks if a specific product is in stock. Do not guess; always check the database first.
Parameters: { "product_name": "string" }

Latency Considerations

Using tools introduces a small delay while the system fetches data. To hide this latency: