Are you maintaining a single long lived spec for an entire repo/project and trying to have AI implement against that, or are you creating a spec for each featur

Are you maintaining a single long lived spec for an entire repo/project and trying to have AI implement against that, or are you creating a spec for each feature addition or piece of work you want to AI to do? What you say I hear commonly from folks who are trying to maintain a single spec for a repo and finding it falls over as that spec gets complex and what’s being asked of the AI is muddied by you asking it to figure out the diff between what was already in the spec/previously implemented and what it’s being asked to do.