This guide covers configuration authoring. It does not provision a phone number, import a trunk, verify carrier support, or establish working transfers. Review telephony availability separately.
Prepare a rule
1
Review the destination
Obtain the intended phone number or SIP URI from its operator. Use approved test destinations in preparation materials; do not treat a syntactically valid value as proof it is reachable.
2
Open the tool editor
On the agent’s Tools > System tools panel, enable Transfer to Number. Complete a transfer rule with a destination and a clear condition. The editor requires at least one complete rule before saving.
3
Review the transfer type
The contract accepts
blind, conference, and sip_refer, with conference as the default. These describe requested transfer modes. Confirm the actual channel and destination support before planning execution.4
Save the authored definition
Save updates the agent working copy. Preserve the reviewed definition in a complete server draft and read back the rules. Keep connection and transfer testing pending.
Destination and optional fields
The definition belongs atconversation_config.agent.prompt.built_in_tools.transfer_to_number. Set params.system_tool_type to transfer_to_number. Its transfers list contains condition, transfer_destination, and optional transfer settings.
The outer
params.enable_client_message defaults to true. Each rule can also contain custom_sip_headers, sip_refer_play_dialtone, uui, and post_dial_digits. Review the exact agent schema before supplying these fields. Do not assume they work on every carrier or transfer type.
Dynamic destinations require the same destination review as static ones. A caller-supplied value must not decide which destinations your service authorizes.
Frequently asked questions
Does a saved number become a Threetone phone number?
Does a saved number become a Threetone phone number?
No. It is a destination in an authored rule. Number ownership, provisioning, carrier configuration, and a supported call path are separate requirements.
Can I rely on a transfer message as success confirmation?
Can I rely on a transfer message as success confirmation?
No. Prepared wording is not a transfer result. Only a verified execution outcome can establish that a handoff completed.