Changelog

New call transfer features: Preserve Caller ID, Summarization Prompt, Call Screening, and Human Detection

We’ve added four new options for live transfer actions, available both in the platform and via the API:

• Preserve Caller ID (preserve_caller_id) — Display the original caller’s phone number to the transfer target instead of the Synthflow agent’s number. Requires a number purchased through the Twilio integration inside Synthflow.
• Summarization Prompt (summarization_prompt) — Provide a custom prompt to control what information is included in the warm transfer summary briefing.
• Call Screening (screened) — Enable call screening so the transfer recipient can speak with the AI agent and accept or decline the call before being connected.
• Human Detection (human_detection) — Wait for a live human to answer before delivering the warm transfer briefing. Use with human_detection_timeout_seconds (30–1800s) to set the detection window.

For setup details, see Phone Number Transfers. For API usage, see Create Action and Update Action.