AI-61: Strip unset None fields from ADK plugin payloads

temporalio/contrib/google_adk_agents/_plugin.py

@@ -10,7 +10,8 @@
 from temporalio.contrib.google_adk_agents._mcp import TemporalMcpToolSetProvider
 from temporalio.contrib.google_adk_agents._model import invoke_model
 from temporalio.contrib.pydantic import (
-    PydanticPayloadConverter as _DefaultPydanticPayloadConverter,
+    PydanticPayloadConverter,
+    ToJsonOptions,
 )
 from temporalio.converter import DataConverter, DefaultPayloadConverter
 from temporalio.plugin import SimplePlugin
@@ -112,10 +113,17 @@ def _configure_data_converter(
     ) -> DataConverter:
         if converter is None:
             return DataConverter(
-                payload_converter_class=_DefaultPydanticPayloadConverter
+                payload_converter_class=_AdkPayloadConverter
             )
         elif converter.payload_converter_class is DefaultPayloadConverter:
             return dataclasses.replace(
-                converter, payload_converter_class=_DefaultPydanticPayloadConverter
+                converter, payload_converter_class=_AdkPayloadConverter
             )
         return converter
+
+
+class _AdkPayloadConverter(PydanticPayloadConverter):
+    """PayloadConverter for Google ADK that strips unset None fields."""
+
+    def __init__(self) -> None:
+        super().__init__(ToJsonOptions(exclude_unset=True))

tests/contrib/google_adk_agents/test_google_adk_agents.py

@@ -14,6 +14,7 @@
 
 """Integration tests for ADK Temporal support."""
 
+import json
 import logging
 import os
 import uuid
@@ -855,3 +856,37 @@ async def test_activity_tool_supports_complex_inputs_via_adk(client: Client):
             ),
             "annotate_trip": "SFO->LAX:3",
         }
+
+
+def test_unset_none_fields_stripped() -> None:
+    """ADK plugin converter strips unset None fields from Pydantic payloads."""
+    plugin = GoogleAdkPlugin()
+    converter = plugin._configure_data_converter(None)
+    request = LlmRequest(
+        model="gemini-2.0-flash",
+        contents=[Content(parts=[Part(text="hello")])],
+    )
+    payloads = converter.payload_converter.to_payloads([request])
+    serialized = json.loads(payloads[0].data)
+
+    assert serialized["model"] == "gemini-2.0-flash"
+    assert "contents" in serialized
+    for field in ("cache_config", "cache_metadata",
+                  "cacheable_contents_token_count", "previous_interaction_id"):
+        assert field not in serialized, f"Unset field {field!r} should be stripped"
+
+
+def test_explicitly_set_none_preserved() -> None:
+    """Explicitly-set None is preserved (exclude_unset, not exclude_none)."""
+    plugin = GoogleAdkPlugin()
+    converter = plugin._configure_data_converter(None)
+    request = LlmRequest(
+        model="gemini-2.0-flash",
+        contents=[Content(parts=[Part(text="hello")])],
+        cache_config=None,
+    )
+    payloads = converter.payload_converter.to_payloads([request])
+    serialized = json.loads(payloads[0].data)
+
+    assert "cache_config" in serialized, "Explicitly-set None should be preserved"
+    assert serialized["cache_config"] is None