Debugging robots made in Google Wave can be a little difficult because it can only be tested on the server and it can be difficult to see how it is sent.
A way I have found is quite useful is to use the app engine log. On the log tab select “Requests only” and then see that data being sent to the robot. It is this data the robot can see, if it is not here then the robot API is not receiving the data.
I hope this help you debug and get at better understanding of your robot.
Update 19 aug 2009: If you want to format the JSON try the JSON formatter.
Starting to develop on Google Wave is easy. You don’t have to install anything, except you need a “Modern Browser” like Firefox 3.5, Chrome, Opera or Safari. You can just login and start experimenting. You need an sandbox account, that you have to register for here.
The best presentation is probably the Google IO keynote found bellow. This gives a great introduction to how wave works.