diff --git a/libs/core/langchain_core/tools.py b/libs/core/langchain_core/tools.py
index e13e641d7cd..50cf500b93b 100644
--- a/libs/core/langchain_core/tools.py
+++ b/libs/core/langchain_core/tools.py
@@ -248,7 +248,11 @@ class ChildTool(BaseTool):
         else:
             if input_args is not None:
                 result = input_args.parse_obj(tool_input)
-                return {k: v for k, v in result.dict().items() if k in tool_input}
+                return {
+                    k: getattr(result, k)
+                    for k, v in result.dict().items()
+                    if k in tool_input
+                }
         return tool_input
 
     @root_validator()