> ... are all excellent requirements documents. No, they are not! They can be a wonderful resource for the validation tests, but a developer needs a model to

> ... are all excellent requirements documents. No, they are not! They can be a wonderful resource for the validation tests, but a developer needs a model to start. The documentation of existing tools may be a nice requirement document, provided it is exhaustive enough. By the way, every time I was requested to implement something "exactly like this gizmo here", I proposed to just keep using that gizmo there, and then the discussion became interesting: "No! We want the same, but...." As soon as the "but" was pronounced, the person in front of me realised the gravity of the situation: they didn't know what they wanted, and by handing me an ancient (despised) tool they were just planning for me to fail and for them to throw me under the bus.