fix: Use the agent name as the author of the audio event

Co-authored-by: Xiang (Sean) Zhou <seanzhougoogle@google.com>
PiperOrigin-RevId: 855789317

src/google/adk/flows/llm_flows/audio_cache_manager.py

@@ -181,10 +181,16 @@ class AudioCacheManager:
       artifact_ref = f'artifact://{invocation_context.app_name}/{invocation_context.user_id}/{invocation_context.session.id}/_adk_live/{filename}#{revision_id}'
 
       # Create event with file data reference to add to session
+      # For model events, author should be the agent name, not the role
+      author = (
+          invocation_context.agent.name
+          if audio_cache[0].role == 'model'
+          else audio_cache[0].role
+      )
       audio_event = Event(
           id=Event.new_id(),
           invocation_id=invocation_context.invocation_id,
-          author=audio_cache[0].role,
+          author=author,
           content=types.Content(
               role=audio_cache[0].role,
               parts=[

tests/unittests/flows/llm_flows/test_audio_cache_manager.py

@@ -387,3 +387,54 @@ class TestAudioCacheManager:
     assert filename.startswith(
         f'adk_live_audio_storage_input_audio_{expected_timestamp_ms}'
     )
+
+  @pytest.mark.asyncio
+  async def test_flush_event_author_for_user_audio(self):
+    """Test that flushed user audio events have 'user' as author."""
+    invocation_context = await testing_utils.create_invocation_context(
+        testing_utils.create_test_agent()
+    )
+
+    # Set up mock artifact service
+    mock_artifact_service = AsyncMock()
+    mock_artifact_service.save_artifact.return_value = 123
+    invocation_context.artifact_service = mock_artifact_service
+
+    # Cache user input audio
+    input_blob = types.Blob(data=b'user_audio_data', mime_type='audio/pcm')
+    self.manager.cache_audio(invocation_context, input_blob, 'input')
+
+    # Flush cache and get events
+    events = await self.manager.flush_caches(
+        invocation_context, flush_user_audio=True, flush_model_audio=False
+    )
+
+    # Verify event author is 'user' for user audio
+    assert len(events) == 1
+    assert events[0].author == 'user'
+    assert events[0].content.role == 'user'
+
+  @pytest.mark.asyncio
+  async def test_flush_event_author_for_model_audio(self):
+    """Test that flushed model audio events have agent name as author, not 'model'."""
+    agent = testing_utils.create_test_agent(name='my_test_agent')
+    invocation_context = await testing_utils.create_invocation_context(agent)
+
+    # Set up mock artifact service
+    mock_artifact_service = AsyncMock()
+    mock_artifact_service.save_artifact.return_value = 123
+    invocation_context.artifact_service = mock_artifact_service
+
+    # Cache model output audio
+    output_blob = types.Blob(data=b'model_audio_data', mime_type='audio/wav')
+    self.manager.cache_audio(invocation_context, output_blob, 'output')
+
+    # Flush cache and get events
+    events = await self.manager.flush_caches(
+        invocation_context, flush_user_audio=False, flush_model_audio=True
+    )
+
+    # Verify event author is agent name (not 'model') for model audio
+    assert len(events) == 1
+    assert events[0].author == 'my_test_agent'  # Agent name, not 'model'
+    assert events[0].content.role == 'model'  # Role is still 'model'