[Petermarcu]

Agreed. If the schema can also generate the service routes, models, serialization, etc, and you just have to maintain the business logic in the service, you get the spec matches the service benefits that way as well. Best of both worlds? People using gRpc seem to be 100% fine with schema first and generating the service stubs.

One of the key things with having the spec is that you can actually describe a lot more than you can with the various attributes and comments in the code. Especially things that are not as much service concerns but potentially client concerns or documentation concerns. You can also encapsulate reusable API patterns so you know different operations are following the same pattern.

The author didn't go into all the details but there are lots of ways in TypeSpec to separate the concerns of different consumers of the spec. There is a lot of opportunity and creative thinking that can be done here.