AR-018 was marked Done while the promotion path still ran on the
constants it was meant to replace. track_gallery.hpp rejected a track
when buffer_spread (1 minus the minimum pairwise cosine) exceeded
expand_track_spread_max, and skipped a view when its raw gal_sim cleared
expand_novelty_sim. Both were bare cosines with no recorded EXCEPTION,
so both were defects under the AR-024 invariant rather than tagging gaps.
The calibrated band was real but unreachable. expand_band_lo/hi were
declared in Config and read nowhere, and set_band() had no callers, so
the gate always ran at the hardcoded 0.90/0.95 while --expand-novelty-sim
and --expand-spread-max stayed live flags.
The spread gate becomes store_coherence: the band's lower bound asked of
every pair in the store, in probability space, rather than a second
constant. admit() compares a newcomer only against its nearest existing
member, so a gradually drifting track chains A to B to C with every step
inside the band while A and C are strangers — the shape a track-ID
collision takes over a slow pan. The bound is re-asked pairwise before
anything reaches an actor's annex.
The novelty gate is deleted rather than converted. SPEC section AR-018
contrasts the band with expand_novelty_sim as the thing it replaces, and
AR-019 requires only that the band is satisfied. Novelty-seeking now
lives entirely in the eviction ordering, which ranks by similarity to the
actor's references instead of cutting at a constant, so there is nothing
left to tune but the two bounds.
BufEntry stored a raw cosine and the eviction loop compared two of them.
The map is monotonic so the ranking was never wrong, but it left a bare
cosine as a decision variable; it now stores the calibrated probability.
The [AR-018] Catch2 tag previously sat on the spread gate, reporting the
replaced mechanism as verification of its replacement. It now sits on the
band: both bounds asserted exactly, since they are inclusive and an
off-by-one there is invisible anywhere else; refusal counted on each
side; and the config bounds driven away from the shipped defaults so a
hardcoded fallback fails. The case that carries the invariant is "band
thresholds probability, not cosine" — under a calibration shifted by
0.10, cosine 0.84 is admitted and cosine 0.92 refused, the opposite of
their raw verdicts. A raw-cosine gate passes an identity-calibrated test
by accident and cannot pass that one. 15 cases, 38 assertions, passing.
scene_preview.cpp takes the flag rename because it would otherwise
reference deleted Config fields. It still does not compile, for reasons
predating this change: it also reads track_max_embed_dist and
track_max_frames_missing, retired by the earlier AR-024 tracker work, and
constructs FaceTrackerFunc with one argument where the registry and
calibration are now required.
Two notes for anyone reading the chain. The main.cpp flag rename and the
AR-018/AR-024 register rows landed in 35e7033, whose trailer names AR-004
only, so git log --grep=AR-018 will not surface them. And
docs/traceability.md is left uncommitted on purpose: regenerating it now
would bake in VR-013 rows for two experiment scripts that are not yet
committed.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
TRACES: AR-018, AR-024 | SR-005
dtourolleandClaude Opus 5
eff696b49a