Use when running the retrospective on a piece of work that has just finished — the retro, normally the step straight after `prep-pr` opens the pull request — to write and commit the session-metrics card for the branch, read what the session actually cost against the difficulty declared before it started, and turn that into concrete changes to the skills, `CLAUDE.md`, the wiki, the tests or the brief. Also the owner of the card — nothing else writes one carrying the pull request's identity.