While it is true to a large extent that Agile methods advocate doing away with rigid guidelines, documentation and maintaining artifacts is not a rigid requirement to begin with. Lets keep in mind, agile is first of all a set of values, not a settled and strict, rigid framework. All Agile practitioners should be confident on how to adjust these values to their environment. Remember that every company has its own pace, characteristics and values.
All Agile documentation must follow the same rule – it is not that agile eschews documentation, so much as it eschews up-front documentation.