for inbound calls, what is the threshold at which the call is "picked up" by the agent? is it when AgentSession.start() is called?

Thanks for reaching out, Ed. I'm an AI assistant and I'm here to help. Give me a moment while I research this topic.

so lets say i get an inbound call and i want to transfer it right away, i dont even really want an agent to join the call, i cant transfer the call while its in a ringing status though

Thanks — I hear you: you want to forward an inbound call immediately, without an agent ever actually joining, but you’re blocked because the call is still in ringing. Short answer: • You cannot transfer a call while it is still in the ringing state. The call must be answered/connected before LiveKit’s transfer APIs can be used. What you can do (two practical options): • Auto-answer and immediately transfer with a lightweight bot ◦ Deploy a minimal automated participant (a bot or lightweight agent) that calls

AgentSession.start()

or otherwise answers the SIP leg as soon as the inbound call arrives. ◦ As soon as the session becomes active, have that bot call the SIP transfer API (for example,

transfer_sip_participant

/ SIP REFER) to redirect the call. The bot can then drop or remain silent so no human agent ever interacts with the caller. ◦ This effectively simulates a pre-answer transfer by answering and immediately performing the transfer. • Handle the redirect at the SIP/provider level before LiveKit ◦ Configure your SIP provider (Twilio, Telnyx, etc.) to perform routing/forwarding rules so the call is redirected before it ever reaches LiveKit. This avoids answering in LiveKit entirely. ◦ Use your provider’s call-control features (e.g., Twilio’s call forwarding/redirect or SIP REFER prior to LiveKit) to achieve immediate transfers. If you’d like, I can help with either approach: • For the bot option I can outline the minimal sequence of calls/events and a small code snippet showing where to call

AgentSession.start()

and then

transfer_sip_participant

. • For the SIP/provider route I can list the provider features to look for and typical configuration patterns. Which approach would you prefer to explore first? Sources: SIP Lifecycle Management Agent | LiveKit Documentation | Company directory phone assistant | LiveKit Documentation | Agents telephony integration | LiveKit Documentation | Handling payments with PCI compliance | LiveKit | Preserve caller ID during SIP transfers with Twilio | LiveKit, with interactive elements

so theres no way to transfer the call and keep it ringing

You're right — there is no way to transfer a call while it stays in the ringing state. Why: LiveKit's transfer operations require the call to be connected/answered first. Transfer APIs (SIP REFER /

transfer_sip_participant

) operate on an active session, not on a ringing leg. Workarounds you can use: • Auto-answer with a lightweight bot ◦ Have a minimal automated participant answer the call (call

AgentSession.start()

or otherwise accept the SIP leg). ◦ Immediately call the transfer API to redirect the call, then drop or stay silent. This gives the effect of an immediate transfer without a human agent interacting. • Handle the redirect at the SIP provider ◦ Configure routing/forwarding rules in your SIP provider (Twilio, Telnyx, etc.) so the call is redirected before it ever reaches LiveKit. This avoids answering in LiveKit entirely. If you want, I can: • Provide a short code sketch for the bot approach showing where to start the session and invoke the transfer. • Outline the specific provider-side features and settings to look for (for common providers like Twilio or Telnyx). Which option would you like to explore? , with interactive elements

is it possible at all to transfer inbound calls without having an agent answer them? like in the request_fnc or anything like that?

Thanks — I understand you want to transfer inbound calls without ever answering them (for example, by using a hook like

request_fnc

) so the call keeps ringing. Short answer: you cannot. Why: transfer operations require an active/answered session. LiveKit’s transfer APIs (SIP REFER /

transfer_sip_participant

) operate on a connected call, not a ringing leg. Programmatic hooks that run while the call is still ringing (such as request handlers) cannot perform a transfer that keeps the call in ringing — the call must be answered first. Practical alternatives you can use: • Auto-answer with a lightweight bot ◦ Have a minimal automatic participant answer immediately (

AgentSession.start()

or equivalent), then invoke the transfer API right away. The bot can then drop or stay silent so no human interacts with the caller. ◦ This effectively simulates an immediate transfer while keeping the caller experience seamless. • Redirect at the SIP/provider level ◦ Configure your SIP provider (Twilio, Telnyx, etc.) to route or forward the call before it reaches LiveKit. Provider-side call-control can redirect calls prior to LiveKit receiving the ringing leg. I can help with next steps: • Provide a short code sketch showing the minimal bot flow (answer → call

transfer_sip_participant

→ exit). • Outline the provider-side features and typical setup for common providers (Twilio/Telnyx) that let you redirect before LiveKit. Which would be most helpful for you? , with interactive elements