I assume that the lone developer locked in the garage is still able to communicate as much as necessary with clients and stakeholders. The garage metaphor makes it sound like they're cut off the whole world, when what I intended was just to isolate them from the development team. Sorry about that; I could have been clearer. So, the developer in the garage would have to be able to interview stakeholders and capture requirements. They are welcome to write their own spec, or stories, or whatever artifacts they prefer, but shouldn't expect to be given a complete spec in most cases.