The first bullet in the "XP Developer Bill of Rights" is: "Programers have a right to know what is needed…" In other words, they have a right to know the requirements. But rights and responsibilities go hand in hand. The fact that we have the right to know what is needed means that we have the responsibility to find out what is needed. That means that programmers play a critical role in the specification of systems. We've learned, over the last few decades, that the best way to specify a system is with tests. So specification disciplines are test disciplines. What are those disciplines? What are the responsibilities that programmers have? What responsibilities do customers, product owners, business analysts, and QA have? Given that specification error is one of the primary reasons for project failure; what must craftsmen do to mitigate and eliminate such errors?