Session Lifecycle & Push-to-Talk (standard)

VCI apps use a three-button session model with an idle timeout. This is the standard — implement it verbatim unless you have a specific reason to deviate.

The three buttons

Button	Visible when	Behavior
Start Session	disconnected	Opens the WebRTC connection to OpenAI. Mic starts muted. Assistant briefly greets.
Push to Talk	connected	Hold to talk (or press Space). On release, audio is committed and the model responds.
End Session	connected / connecting	Explicitly closes the WebRTC connection.

Session phases

Phase	Meaning
disconnected	No WebRTC connection. Only Start Session is visible.
connecting	Establishing WebRTC + minting ephemeral token.
connected	Session live, mic muted, waiting for PTT press. PTT + End Session visible.

Status pill states

The status pill sits alongside the buttons and reflects the moment-to-moment state of the assistant:

Status	Meaning
idle	No session, or session live but nothing happening.
listening	User is holding PTT; mic is streaming.
thinking	Audio committed; model is processing / running a tool.
speaking	Model is streaming its spoken response.
error	Something failed; details in log.

Push-to-Talk interaction

• Press (pointerdown on the PTT button OR keydown on Space):
  • Call Realtime.startTurn() — sends input_audio_buffer.clear and sets micTrack.enabled = true.
  • Set status → listening, apply the .is-recording visual state.
• Release (pointerup / pointercancel / pointerleave while recording, OR keyup on Space):
  • Call Realtime.endTurn() — sets micTrack.enabled = false, then sends input_audio_buffer.commit and response.create.
  • Set status → thinking, disable the PTT button briefly.
  • On response.done, re-enable PTT and set status → idle.
• Barge-in: if the user presses PTT while the model is speaking, call Realtime.interruptResponse() (sends response.cancel) before startTurn().

Support both pointer events (mouse / touch / pen) and the Space bar as an accessibility fallback. Ignore Space when typing in inputs.

Inactivity timeout (auto-close)

Sessions auto-close after 3 minutes with no PTT activity.

• Start a setTimeout when the phase enters connected.
• Reset the timeout every time PTT is released (i.e. after a completed user turn).
• On timeout: call endSession(), log "Session auto-closed after 3 minutes of inactivity." in the conversation log.
• Clear the timeout when the phase leaves connected (manual end or connection failure).

Why 3 minutes?

The Realtime API bills per minute of active connection. An abandoned session sitting connected can accrue meaningful cost. Three minutes is a good default; expose it as a constant so apps can tune it.