Hi Bill, this wasn't available but based on your feedback I've now updated the custom webhook call so that there is an option to use the JSON structure to name the parameters. By checking the 'use JSON structure' checkbox, it will pull the names from the JSON.
I see you're using a weather webhook call. For that particular webhook, if you're after the weather conditions the parameter name is {weather-0-description}. The 0 in the parameter name is due to the way the JSON data is structured.
Let me know if you have any questions.