fixed missing return type

agent.py

@@ -77,9 +77,9 @@ def modulus(a:int, b:int) -> int:
 
 
 @tool
-def rounder(a:float, n:int):
+def rounder(a:float, n:int) -> float:
   """
-  This tool rounds a number to a certain number of decimals.
+  This tool return a number rounded to a certain number of decimals.
 
   Args:
     a: number to be rounded