chore: Exclude thought_signature from ADK event outputs

PiperOrigin-RevId: 781686120

Author: shawn-yang-google

tests/unit/vertex_adk/test_reasoning_engine_templates_adk.py

@@ -102,6 +102,7 @@ def run(self, *args, **kwargs):
                 "content": {
                     "parts": [
                         {
+                            "thought_signature": b"test_signature",
                             "function_call": {
                                 "args": {
                                     "currency_date": "2025-04-03",
@@ -110,7 +111,7 @@ def run(self, *args, **kwargs):
                                 },
                                 "id": "af-c5a57692-9177-4091-a3df-098f834ee849",
                                 "name": "get_exchange_rate",
-                            }
+                            },
                         }
                     ],
                     "role": "model",
@@ -129,6 +130,7 @@ async def run_async(self, *args, **kwargs):
                 "content": {
                     "parts": [
                         {
+                            "thought_signature": b"test_signature",
                             "function_call": {
                                 "args": {
                                     "currency_date": "2025-04-03",
@@ -137,7 +139,7 @@ async def run_async(self, *args, **kwargs):
                                 },
                                 "id": "af-c5a57692-9177-4091-a3df-098f834ee849",
                                 "name": "get_exchange_rate",
-                            }
+                            },
                         }
                     ],
                     "role": "model",
@@ -400,6 +402,30 @@ def test_enable_tracing_warning(self, caplog):
         # assert "enable_tracing=True but proceeding with tracing disabled" in caplog.text
 
 
+def test_dump_event_for_json():
+    from google.adk.events import event
+
+    test_event = event.Event(
+        **{
+            "author": "test_agent",
+            "content": {
+                "parts": [
+                    {
+                        "thought_signature": b"test_signature",
+                        "text": "This is a test",
+                    }
+                ],
+                "role": "model",
+            },
+            "id": "test_id",
+            "invocation_id": "test_invocation_id",
+        }
+    )
+    dumped_event = _utils.dump_event_for_json(test_event)
+    assert "thought_signature" not in dumped_event["content"]["parts"][0]
+    assert "text" in dumped_event["content"]["parts"][0]
+
+
 @pytest.mark.usefixtures("mock_adk_version")
 class TestAdkAppErrors:
     def test_raise_get_session_not_found_error(self):

vertexai/agent_engines/_utils.py

@@ -91,6 +91,13 @@
 except ImportError:
     AutogenRunResponse = Any
 
+try:
+    import pydantic
+
+    BaseModel = pydantic.BaseModel
+except ImportError:
+    BaseModel = Any
+
 JsonDict = Dict[str, Any]
 
 
@@ -610,6 +617,14 @@ def is_noop_or_proxy_tracer_provider(tracer_provider) -> bool:
     return isinstance(tracer_provider, (NoOpTracerProvider, ProxyTracerProvider))
 
 
+def dump_event_for_json(event: BaseModel) -> Dict[str, Any]:
+    """Dumps an ADK event to a JSON-serializable dictionary."""
+    return event.model_dump(
+        exclude_none=True,
+        exclude={"content": {"parts": {"__all__": {"thought_signature"}}}},
+    )
+
+
 def _import_cloud_storage_or_raise() -> types.ModuleType:
     """Tries to import the Cloud Storage module."""
     try:

vertexai/preview/reasoning_engines/templates/adk.py

@@ -181,11 +181,13 @@ def __init__(self, **kwargs):
         # List of artifacts belonging to the session.
 
     def dump(self) -> Dict[str, Any]:
+        from vertexai.agent_engines import _utils
+
         result = {}
         if self.events:
             result["events"] = []
             for event in self.events:
-                event_dict = event.model_dump(exclude_none=True)
+                event_dict = _utils.dump_event_for_json(event)
                 event_dict["invocation_id"] = event_dict.get("invocation_id", "")
                 result["events"].append(event_dict)
         if self.artifacts:
@@ -556,6 +558,7 @@ def stream_query(
         Yields:
             The output of querying the ADK application.
         """
+        from vertexai.agent_engines import _utils
         from google.genai import types
 
         if isinstance(message, Dict):
@@ -576,7 +579,7 @@ def stream_query(
         for event in self._tmpl_attrs.get("runner").run(
             user_id=user_id, session_id=session_id, new_message=content, **kwargs
         ):
-            yield event.model_dump(exclude_none=True)
+            yield _utils.dump_event_for_json(event)
 
     async def async_stream_query(
         self,
@@ -603,6 +606,7 @@ async def async_stream_query(
         Yields:
             Event dictionaries asynchronously.
         """
+        from vertexai.agent_engines import _utils
         from google.genai import types
 
         if isinstance(message, Dict):
@@ -627,7 +631,7 @@ async def async_stream_query(
 
         async for event in events_async:
             # Yield the event data as a dictionary
-            yield event.model_dump(exclude_none=True)
+            yield _utils.dump_event_for_json(event)
 
     def streaming_agent_run_with_events(self, request_json: str):
         import json