diff --git a/validator/tool_calls.py b/validator/tool_calls.py
index fce8861..8ed4f70 100644
--- a/validator/tool_calls.py
+++ b/validator/tool_calls.py
@@ -101,7 +101,7 @@ def validate_tool_call(self, tool_call: dict, tools: list[dict]) -> bool:
             validate(instance=args, schema=schema)
             return True
         except (json.JSONDecodeError, ValidationError) as e:
-            print("Schema validation failed: {e}")
+            print(f"Schema validation failed: {e}")
             return False
         except Exception as e:
             print(f"Unexpected validation error: {e}")