feat(live): support Live API translation config in RunConfig

Author: allen-stephen

src/google/adk/agents/run_config.py

@@ -239,6 +239,9 @@ class RunConfig(BaseModel):
   realtime_input_config: Optional[types.RealtimeInputConfig] = None
   """Realtime input config for live agents with audio input from user."""
 
+  translation_config: Optional[types.StreamTranslationConfig] = None
+  """Configures real-time speech-to-speech translation for live agents."""
+
   enable_affective_dialog: Optional[bool] = None
   """If enabled, the model will detect emotions and adapt its responses accordingly."""
 

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

@@ -83,6 +83,9 @@ def _build_basic_request(
   llm_request.live_connect_config.realtime_input_config = (
       invocation_context.run_config.realtime_input_config
   )
+  llm_request.live_connect_config.stream_translation_config = (
+      invocation_context.run_config.translation_config
+  )
   active_model_name = (
       getattr(getattr(agent, 'canonical_live_model', None), 'model', None)
       or llm_request.model

tests/unittests/flows/llm_flows/test_basic_processor.py

@@ -254,3 +254,45 @@ async def test_keeps_affective_dialog_and_proactivity_for_non_gemini_3_1(
 
     assert llm_request.live_connect_config.enable_affective_dialog is True
     assert llm_request.live_connect_config.proactivity is not None
+
+  @pytest.mark.asyncio
+  async def test_sets_translation_config(self):
+    """Translation config is forwarded to the live connect config."""
+    agent = LlmAgent(
+        name='test_agent',
+        model='gemini-3.5-live-translate-preview',
+    )
+    invocation_context = await _create_invocation_context(agent)
+    invocation_context.run_config = RunConfig(
+        translation_config=types.StreamTranslationConfig(
+            target_language_code='pl',
+            echo_target_language=True,
+        ),
+    )
+    llm_request = LlmRequest()
+    processor = _BasicLlmRequestProcessor()
+
+    async for _ in processor.run_async(invocation_context, llm_request):
+      pass
+
+    stream_translation_config = (
+        llm_request.live_connect_config.stream_translation_config
+    )
+    assert stream_translation_config.target_language_code == 'pl'
+    assert stream_translation_config.echo_target_language is True
+
+  @pytest.mark.asyncio
+  async def test_translation_config_defaults_to_none(self):
+    """Without a translation config the live connect field stays None."""
+    agent = LlmAgent(
+        name='test_agent',
+        model='gemini-2.5-flash-live',
+    )
+    invocation_context = await _create_invocation_context(agent)
+    llm_request = LlmRequest()
+    processor = _BasicLlmRequestProcessor()
+
+    async for _ in processor.run_async(invocation_context, llm_request):
+      pass
+
+    assert llm_request.live_connect_config.stream_translation_config is None