diff --git a/swarms/tools/tool.py b/swarms/tools/tool.py
index 105a2541..89c09d53 100644
--- a/swarms/tools/tool.py
+++ b/swarms/tools/tool.py
@@ -268,7 +268,7 @@ class ChildTool(BaseTool):
                 }
         return tool_input
 
-    @root_validator()
+    @model_validator(mode="after")
     def raise_deprecation(cls, values: Dict) -> Dict:
         """Raise deprecation warning if callback_manager is used."""
         if values.get("callback_manager") is not None: