fix(openai): keep the keys beside "result" in a Responses tool output

src/google/adk/integrations/openai/_openai_responses_llm.py

@@ -160,7 +160,9 @@ def _serialize_json_value(value: object) -> str:
       return '\n'.join(content_items)
     if isinstance(content, str) and content:
       return content
-    if 'result' in value and value['result'] is not None:
+    # Exactly {'result': value} is ADK's wrapper for a non-dict tool return. A
+    # tool's own dict that merely has a 'result' key is sent whole.
+    if value.keys() == {'result'} and value['result'] is not None:
       result = value['result']
       if isinstance(result, str):
         return result

tests/unittests/integrations/openai/test_openai_responses_llm.py

@@ -14,6 +14,7 @@
 
 from __future__ import annotations
 
+import json
 import logging
 from unittest import mock
 
@@ -369,6 +370,37 @@ def test_content_mapping_sanitizes_function_call_ids_per_request():
   assert items[3]['call_id'] == 'call_adk_fallback_2'
 
 
+def _function_output(response: dict[str, object]) -> str:
+  content = types.Content(
+      role='tool',
+      parts=[
+          types.Part(
+              function_response=types.FunctionResponse(
+                  id='call_123', name='tool', response=response
+              )
+          )
+      ],
+  )
+  return _content_to_response_input_items(content)[0]['output']
+
+
+def test_function_response_unwraps_adk_result_wrapper():
+  """Exactly {"result": value} is ADK's wrapper for a non-dict tool return."""
+  assert _function_output({'result': 'sunny'}) == 'sunny'
+  assert _function_output({'result': [1, 2]}) == '[1, 2]'
+
+
+def test_function_response_keeps_keys_beside_result():
+  """A tool dict that merely has a "result" key is sent whole."""
+  response = {
+      'result': 'found 2 contracts',
+      'contracts': ['NDA-12', 'MSA-7'],
+      'next_page_token': 'abc',
+  }
+
+  assert json.loads(_function_output(response)) == response
+
+
 def test_function_response_serializes_mcp_content_as_text():
   """MCP-style text content is flattened for function_call_output."""
   content = types.Content(