[realtime] Add direct access to model layer from session (#1172)

Author: rm-openai

docs/realtime/guide.md

@@ -138,6 +138,17 @@ Send audio to the session using [`session.send_audio(audio_bytes)`][agents.realt
 
 For audio output, listen for `audio` events and play the audio data through your preferred audio library. Make sure to listen for `audio_interrupted` events to stop playback immediately and clear any queued audio when the user interrupts the agent.
 
+## Direct model access
+
+You can access the underlying model to add custom listeners or perform advanced operations:
+
+```python
+# Add a custom listener to the model
+session.model.add_listener(my_custom_listener)
+```
+
+This gives you direct access to the [`RealtimeModel`][agents.realtime.model.RealtimeModel] interface for advanced use cases where you need lower-level control over the connection.
+
 ## Examples
 
 For complete working examples, check out the [examples/realtime directory](https://github.com/openai/openai-agents-python/tree/main/examples/realtime) which includes demos with and without UI components.

src/agents/realtime/session.py

@@ -107,6 +107,11 @@ def __init__(
 
         self._guardrail_tasks: set[asyncio.Task[Any]] = set()
 
+    @property
+    def model(self) -> RealtimeModel:
+        """Access the underlying model for adding listeners or other direct interaction."""
+        return self._model
+
     async def __aenter__(self) -> RealtimeSession:
         """Start the session by connecting to the model. After this, you will be able to stream
         events from the model and send messages and audio to the model.