burndown.py averaged the last 3 INTER-COMMIT deltas. The phase's ROI criterion is
"per-SESSION yield floors out", and historically one snapshot was taken per session
— but I seeded THREE inside this session (9, 9b, 9c). Averaging them drove the mean
to +0.23 and printed "AT THE FLOOR — consider closing P29" for a session that
actually yielded +0.7pp instr (78.0 -> 78.7), comparable to recent sessions.
I nearly closed the phase on it. Same error class as everything else this session:
an instrument answering a DIFFERENT QUESTION than the one asked, where the wrong
answer is indistinguishable from the right one.
- --session-close marks a snapshot as a session boundary; the floor verdict is now
computed ONLY from those (older records predate the flag, so a label containing
"close" counts too). Mid-session snapshots still record for tracking.
- honest output now: "0 SESSION-to-SESSION delta(s) logged — need >=3 for a floor
verdict (1 session-close snapshot on record)".
=> P29 must NOT close on ROI grounds yet: the floor is UNDETERMINED and needs 3
session closes to become computable. The eyeballed "+2.5 -> +1.1 -> +0.6 -> +0.2"
trend is not the instrument's verdict either.
tools/burndown.py snapshots the 3 fleet metrics + remaining substantial frontier
each run (docs/burndown.jsonl, git-HEAD-keyed), computes velocity vs the previous
commit-snapshot, and flags the yield floor (mean instr-pp over last 3 snapshots <
threshold => 'consider closing P29'). Seeded with the session-4-close baseline.
Reads progress.fleet.md + family-hseq.md (regen those first for a true reading).
Drew T