google · Lin-Nikaido · Jul 17, 2025 · Jul 17, 2025 · Jul 17, 2025 · Jul 18, 2025
diff --git a/src/google/adk/flows/llm_flows/base_llm_flow.py b/src/google/adk/flows/llm_flows/base_llm_flow.py
@@ -466,16 +466,18 @@ async def _postprocess_handle_function_calls_async(
       function_call_event: Event,
       llm_request: LlmRequest,
   ) -> AsyncGenerator[Event, None]:
-    if function_response_event := await functions.handle_function_calls_async(
+    if function_response_event_generator := functions.handle_function_calls_async(
         invocation_context, function_call_event, llm_request.tools_dict
     ):
-      auth_event = functions.generate_auth_event(
-          invocation_context, function_response_event
-      )
-      if auth_event:
-        yield auth_event
+      async for function_response_event in function_response_event_generator:
+        auth_event = functions.generate_auth_event(
+            invocation_context, function_response_event
+        )
+        if auth_event:
+          yield auth_event
+
+        yield function_response_event
 
-      yield function_response_event
       transfer_to_agent = function_response_event.actions.transfer_to_agent
       if transfer_to_agent:
         agent_to_run = self._get_agent_to_run(

diff --git a/src/google/adk/flows/llm_flows/functions.py b/src/google/adk/flows/llm_flows/functions.py
@@ -22,6 +22,7 @@
 from typing import Any
 from typing import AsyncGenerator
 from typing import cast
+from typing import Union
 from typing import Optional
 import uuid
 
@@ -128,17 +129,17 @@ async def handle_function_calls_async(
     function_call_event: Event,
     tools_dict: dict[str, BaseTool],
     filters: Optional[set[str]] = None,
-) -> Optional[Event]:
+) -> AsyncGenerator[Optional[Event], None]:
   """Calls the functions and returns the function response event."""
   from ...agents.llm_agent import LlmAgent
 
   agent = invocation_context.agent
   if not isinstance(agent, LlmAgent):
+    yield None
     return
 
   function_calls = function_call_event.get_function_calls()
 
-  function_response_events: list[Event] = []
   for function_call in function_calls:
     if filters and function_call.id not in filters:
       continue
@@ -217,33 +218,50 @@ async def handle_function_calls_async(
         if not function_response:
           continue
 
-      # Builds the function response event.
-      function_response_event = __build_response_event(
-          tool, function_response, tool_context, invocation_context
-      )
-      trace_tool_call(
-          tool=tool,
-          args=function_args,
-          function_response_event=function_response_event,
-      )
-      function_response_events.append(function_response_event)
-
-  if not function_response_events:
-    return None
-  merged_event = merge_parallel_function_response_events(
-      function_response_events
-  )
+      function_response_events: list[Event] = []
+      async for function_response_one in _ensure_async_generator_function_response(
+              function_response
+      ):
+        # Builds the function response event.
+        function_response_event = __build_response_event(
+            tool, function_response_one, tool_context, invocation_context
+        )
+        trace_tool_call(
+            tool=tool,
+            args=function_args,
+            function_response_event=function_response_event,
+        )
+        function_response_events.append(function_response_event)
 
-  if len(function_response_events) > 1:
-    # this is needed for debug traces of parallel calls
-    # individual response with tool.name is traced in __build_response_event
-    # (we drop tool.name from span name here as this is merged event)
-    with tracer.start_as_current_span('execute_tool (merged)'):
-      trace_merged_tool_calls(
-          response_event_id=merged_event.id,
-          function_response_event=merged_event,
-      )
-  return merged_event
+        if not function_response_events:
+          yield None
+          return
+        merged_event = merge_parallel_function_response_events(
+            function_response_events
+        )
+        if len(function_response_events) > 1:
+          # this is needed for debug traces of parallel calls
+          # individual response with tool.name is traced in __build_response_event
+          # (we drop tool.name from span name here as this is merged event)
+          with tracer.start_as_current_span('execute_tool (merged)'):
+            trace_merged_tool_calls(
+                response_event_id=merged_event.id,
+                function_response_event=merged_event,
+            )
+        yield merged_event
+
+
+async def _ensure_async_generator_function_response(
+        function_response: Union[str, dict, AsyncGenerator]
+) -> AsyncGenerator[Optional[Union[str, dict]], None]:
+    if inspect.isasyncgen(function_response):
+        async for response in function_response:
+            yield response
+    elif inspect.isgenerator(function_response):
+        for response in function_response:
+            yield response
+    else:
+        yield function_response
 
 
 async def handle_function_calls_live(
@@ -587,4 +605,4 @@ def find_matching_function_call(
       for function_call in function_calls:
         if function_call.id == function_call_id:
           return event
-  return None
+  return None