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What is Call Transfer?

Call transfer enables your Voice AI agent to route live calls to human agents or specific phone numbers based on conversation context. Essential for escalations, specialized support, or when human intervention is needed.

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Configuration Options

Transfer call configuration showing Description prompt, phone number field, pre-tool message with multi-language support, and custom server URL option
SettingDescription
Description (Prompt)Tell the LLM when to trigger the transfer. Be specific - e.g., “Transfer when caller requests to speak with a human agent or sales team.”
Transfer to phone numberDestination number in international format (e.g., +19876543210)
Pre-tool messageWhat the agent says while transferring - e.g., “Sure, I’ll transfer the call for you. Please wait a moment.” Supports multiple languages.
Add multiple languages for pre-tool messages using + Add to support multilingual callers.

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How to Set Up Call Transfer

1

Open Tools Tab

Navigate to the Tools Tab in your agent configuration.
2

Select Transfer Call

Click “Select functions” → choose “Transfer Call” from the dropdown.
3

Configure Phone Number

Enter the destination phone number where calls should be transferred.
4

Write a Clear Description

Describe when the transfer should trigger - e.g., “Transfer when caller asks for sales, pricing, or demos.”
5

Add Pre-tool Message

Set the message your agent speaks while initiating the transfer.
6

Save Configuration

Click Save transfer call to apply your settings.
Multiple departments? Add separate transfer functions for Sales, Support, Billing - each with its own phone number and trigger description.

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Custom Server URL (Advanced)

For dynamic routing, enable “Receive transfer call on your own server URL” to handle transfers with custom logic.
Custom URL configuration showing endpoint field and JSON parameters schema for custom transfer logic
SettingDescription
Custom URLYour server endpoint that accepts POST requests
ParametersJSON schema defining variables your endpoint expects

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Example Parameters Schema

{
  "type": "object",
  "properties": {
    "department": {
      "type": "string",
      "description": "Department to transfer to"
    },
    "caller_id": {
      "type": "string", 
      "description": "Caller's phone number"
    }
  },
  "required": ["department"]
}
Your endpoint receives a POST request with the configured parameters. Return a JSON response with phone_number to complete the transfer dynamically.

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Example Conversation

Caller: “I’d like to speak with someone from your sales team.”Agent: “Sure, I’ll transfer you to our sales team. Please wait a moment…”Agent triggers transfer_call function → Call is routed to configured sales number

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Best Practices

Be Specific

Use detailed descriptions like “Transfer to sales when caller asks about pricing, demos, or purchasing” instead of generic “Transfer call”

Test Phone Numbers

Verify destination numbers are correct and always reachable before deploying

Use Pre-tool Messages

Always set a friendly message so callers know they’re being transferred

Handle Failures

Have a fallback plan if the destination is busy or unavailable
Test before deploying! Failed transfers frustrate callers. Always verify phone numbers are correct and reachable.

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Next Steps

Custom Functions

Build custom API integrations for your agent

Check Calendar Slots

Query availability via Cal.com integration

Book Appointments

Schedule meetings during live calls

Tools Tab Guide

Complete function configuration guide