diff --git a/src/google/adk/tools/openapi_tool/openapi_spec_parser/operation_parser.py b/src/google/adk/tools/openapi_tool/openapi_spec_parser/operation_parser.py
index f7a577afb2..3076cd8502 100644
--- a/src/google/adk/tools/openapi_tool/openapi_spec_parser/operation_parser.py
+++ b/src/google/adk/tools/openapi_tool/openapi_spec_parser/operation_parser.py
@@ -165,7 +165,7 @@ def _process_return_value(self) -> Parameter:
     """Returns a Parameter object representing the return type."""
     responses = self._operation.responses or {}
     # Default to Any if no 2xx response or if schema is missing
-    return_schema = Schema(type='Any')
+    return_schema = Schema(type='object')
 
     # Take the 20x response with the smallest response code.
     valid_codes = list(