I have to admit, this is very reminiscent of "Add Service Reference" in Visual Studio, a capability to which I have grown to despise over the years. The code was almost always incomprehensible. I cannot tell you how much I loath seeing the comment at the top of a file "This was generated by a tool".

Having said that, this tool does look interesting. I hope that a goal is to always make sure that the generated code is as readable, and maintainable, as possible. Also, as mentioned by others, adding generated tests to the generated client libraries is extremely important.