session-openlisted

# Skill — Session-open checkpoint > The cheapest of the three, and the one that changes the most. A defect caught here costs a paragraph; > the same defect caught at pre-commit costs the diff that was built on it. _(Part of the `checkpoints` > ritual pack — see [`../../README.md`](../../README.md) for the verdict vocabulary in full and for > what this pack cannot enforce.)_ ## When to use it At the opening of **full-lane** work, before the implementer writes to any file. **Where the lane boundary sits is the adopting workspace's, not this pack's.** Core defines two lanes and leaves the boundary to the workspace ([`../../../../../core/operating/loop.md`](../../../../../core/operating/loop.md)). A pack that imposed three checkpoints on every one-line fix would be ceremony that cannot scale down — a named non-goal, and the fastest way to get a ritual switched off wholesale. Read the workspace's own threshold and honour it. ## The pass 1. **Read the criterion the session claims to serve, as an input rather than as background.** If it reads two ways, that ambiguity is the finding — say so before the session builds one of the two readings by guessing. A criterion is the standard; a plan that quietly narrows it has already failed and nothing downstream will notice. 2. **Read the workspace's own slots** — constitution or principles, definition-of-done, gate map — and grade the plan against what this team wrote down, never against your own taste. A supervisor subs