I encourage everyone interested in software development to read it.

Drew has also posted a great recording: https://www.youtube.com/watch?v=8TXAlOFkmk0 and an open source tool https://github.com/dbreunig/plumb

This is interesting. It seems like it may only be applicable to brand new projects though. Could you envision it working for large, existing applications that wouldn't have specs for the existing code?