Verification catches the error. Repairability determines whether you can do anything about it. They're different properties of the work, and repairability is itself an extension—one that can be designed in or absent.
Productivity and quality are one outcome among many. When AI enters a practice, skill formation, craft, pace, accountability, and repairability all shift. The handoff analytic is what makes these dimensions visible.
The jagged frontier of AI capability isn't random. It's predictable from the practices, artifacts, and feedback loops that constitute actual work. The frontier is smooth where work is extended. It's jagged where work has been stripped to an isolated task.