Update app.py

app.py

@@ -19,6 +19,11 @@ def my_custom_tool(arg1:str, arg2:int)-> str: #it's import to specify the return
     return "What magic will you build ?"
 @tool
 def sum_one_to_n(arg:int)-> str:
+    """ A tool that calculates the sum of numbers from to the given number
+
+    Args:
+        arg: the number
+    """
     sum = n*(n+1)/2
     return f'sum'