Update app.py

app.py

@@ -133,7 +133,10 @@ def get_run_steps(client, thread, run):
 
 def execute_tool_call(tool_call):
     name = tool_call.function.name
-    args = json.loads(tool_call.function.arguments)
+    args = {}
+
+    if tool_call.function.arguments:
+        args = json.loads(tool_call.function.arguments)
 
     return tools[name](**args)