Unit 2 was written as one block, but CB-571/576/580 and unit 2a have since
built parts of it. A symbol survey of main source plus the merge history puts
it at 1 of 21 criteria done, with three partials.
Criterion 15 says a normal COMPLETED release removes the worktree. Since
CB-576 that is false on purpose — a dirty worktree is preserved, because
deleting it destroys work that cannot be recovered. The criterion is wrong,
not the code.
The criterion required the token to bind the session turn number. Three
independent refusals from the implementer showed why that is not
implementable at this layer: MessageService owns acceptance but never
learns of delivery, and CompletionResolver.onDelivered runs before
SessionManager.onDelivered, so the turn number does not exist yet at the
only point the token could capture it.
Records both rejected alternatives and why, so the next reader does not
re-derive them: a target-keyed registry restores the ambiguity the token
exists to remove, and injecting a turn counter couples layers to fill a
field nothing reads yet.
Dai Ha