In our experience, living specs work better as a versioned source of truth for how the product should behave. A change proposal describes the delta, while the living specs describe the resulting system. Revision history makes changes easier to manage and helps the agent understand exactly what changed.

Verifying against incremental specs alone is harder because they leave the behavior that should remain unchanged to be reconstructed. With a maintained current specification, we can verify the affected code against that source of truth after each change. That's the approach we've built into Reqode.