Class BaseRealtimeModelAbstract

The provider-native voice ids this model can speak with (e.g. OpenAI alloy/echo/shimmer). The model/driver is the authoritative owner of "what voices do I support", so each driver declares its own — used to populate the dev voice picker. Default empty (a driver that hasn't declared voices yields no picker options, falling back to the configured/default voice).

NOTE: this is the near-term, driver-owned source of truth. Long term this should move to metadata so providers that let users add their OWN voices (e.g. ElevenLabs) can be enumerated dynamically.

Whether this driver can mint an ephemeral, server-scoped client credential for a client-direct realtime session (the browser opens its own provider socket using a short-lived token the server minted).

Defaults to false. Providers that support browser-direct sessions override this to true and implement CreateClientSession. The server-bridged topology (where the provider socket lives on the server, via StartSession) is supported by every driver regardless of this flag.

Whether this driver's sessions carry a video track in addition to audio — i.e. the model accepts video input (it can "see" the user's camera) and/or emits video output (a talking-head avatar / generated video), in sync with audio.

Defaults to false (audio-only — today's realtime models). Video-capable drivers (a native multimodal realtime model, or an avatar provider) override this to true. The session's media plane is media-tagged (IRealtimeSession.SendInput takes a RealtimeMediaKind; IRealtimeSession.OnVideoOutput delivers video-out), so a video session reuses the entire realtime contract — only the media frames gain a video kind. Resolution prefers a video-capable model when an agent requests video, and degrades to audio-only otherwise.

Mints an ephemeral, server-scoped client credential plus a provider-native session config for a client-direct realtime session.

In the client-direct topology the browser owns the provider socket (e.g. WebRTC), but the server still controls the prompt and tool set: it mints a short-lived token and hands back a ClientRealtimeSessionConfig whose SessionConfig the matching client driver applies when it opens its socket. This keeps prompt/tool authority server-side even though the media plane is client-direct.

Not every provider supports this (some only expose a server-bridged socket), so this is a concrete method that throws by default rather than an abstract one — that would force every existing and future driver to implement it. Providers that support it override SupportsClientDirect to true and override this method.

Opens a stateful duplex session with the provider.

The returned IRealtimeSession is the long-lived handle that streams media and transcripts in both directions, surfaces tool calls and usage telemetry, and reports provider-detected interruptions (barge-in). The caller is responsible for closing the session via IRealtimeSession.Close.