fix(anthropic): preserve sibling keys beside function_response result

src/google/adk/models/anthropic_llm.py

@@ -514,15 +514,17 @@ def _part_to_message_block(
     # SDK ref: anthropic.types.tool_result_block_param
     # https://github.com/anthropics/anthropic-sdk-python/blob/main/src/anthropic/types/tool_result_block_param.py
     # Exactly {"result": value} is ADK's wrapper for a non-dict tool return.
-    elif (
-        response_data.keys() == {"result"}
-        and response_data["result"] is not None
-    ):
-      result = response_data["result"]
-      if isinstance(result, (dict, list)):
-        content = json.dumps(result)
+    # If sibling keys exist beside result, serialize the whole dict so Claude
+    # matches Gemini (issue #7073).
+    elif "result" in response_data and response_data["result"] is not None:
+      if response_data.keys() == {"result"}:
+        result = response_data["result"]
+        if isinstance(result, (dict, list)):
+          content = json.dumps(result)
+        else:
+          content = str(result)
       else:
-        content = str(result)
+        content = json.dumps(response_data, default=str)
     elif response_data:
       # Fallback: serialize the entire response dict as JSON so that tools
       # returning arbitrary key structures (e.g. load_skill returning

tests/unittests/models/test_anthropic_llm.py

@@ -928,6 +928,25 @@ def test_part_to_message_block_with_traditional_result():
   assert "This is the result from the tool" in result["content"]
 
 
+def test_part_to_message_block_preserves_sibling_keys_with_result():
+  """Issue #7073: sibling keys next to result must reach Claude."""
+  response_part = types.Part.from_function_response(
+      name="run_python_analysis",
+      response={
+          "result": {"matched": 33, "total": 49},
+          "files": [{"filename": "matching.xlsx", "bytes": 8684}],
+          "stdout": "Saved to /tmp/outputs/matching.xlsx\n",
+      },
+  )
+  response_part.function_response.id = "toolu_01"
+
+  result = part_to_message_block(response_part)
+  parsed = json.loads(result["content"])
+  assert parsed["result"] == {"matched": 33, "total": 49}
+  assert parsed["files"] == [{"filename": "matching.xlsx", "bytes": 8684}]
+  assert parsed["stdout"] == "Saved to /tmp/outputs/matching.xlsx\n"
+
+
 def test_part_to_message_block_with_multiple_content_items():
   """Test content with multiple items."""
   from google.adk.models.anthropic_llm import part_to_message_block