updated tools-calling doc

Signed-off-by: Sahil Suman <sahilsuman933@gmail.com>

Author: sahilsuman933

tools-calling.mdx

@@ -130,5 +130,6 @@ Let's revisit the weather tool example from before. If the tool successfully ret
 
 - Pay attention to the required parameters and response format of your functions.
 - Ensure your server is accessible and can handle the incoming requests from Vapi.
+- Make sure to add "Tools Calls" in both the Server and Client messages and remove the function calling from it.
 
 By following these guidelines and adapting the sample payload, you can easily configure a variety of tools to expand your Vapi assistant's capabilities and provide a richer, more interactive user experience.