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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.

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Overview

Transfer Call enables your agent to hand off a conversation to a human agent or another destination mid-call.

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Setup

1

Add the tool

In your agent’s Functions section, select Transfer Call from the dropdown.
2

Configure the transfer destination

Provide the number or SIP URI to transfer to:
FormatExample
E.164 phone number+14158923245
SIP URIsip:username@domain.com
You can also include optional extensions, or use dynamic variables to set the destination at runtime.
3

Update your prompt

Tell the agent when to trigger a transfer. Example:
If the caller sounds frustrated or requests a human agent, use the transfer_call tool to route them to a representative.

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Transfer Types

Cold Transfer

Direct handoff. The AI agent disconnects immediately after routing the call — no introduction.

Warm Transfer

The AI agent stays on briefly to detect human presence, deliver a whisper message, and introduce the caller before dropping off.

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Warm Transfer Options

SettingDescription
On-hold musicPlayed while connecting
IVR navigation promptsNavigate menus before reaching a human
Human detection timeoutDefault 30 seconds
Auto-greetingAgent speaks when human answers
Whisper messagePrivate message delivered to the recipient only
Three-way introductionAgent introduces caller before dropping off

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Additional Options

  • Caller ID: Show the agent’s number or the original caller’s number (depends on telephony provider support)
  • Custom SIP headers: Add headers prefixed with X- or labeled User-To-User for routing and metadata