The key is read and rewritten IN FULL on every run and holds base64
conditioning tensors, so its cost grows with everything ever learned — which
is what "2.0s, then 2.4s" looks like from outside. Timing the read and the
write, with the file size and the entry counts of the collections that can
grow without bound, says whether that is where the time goes and which
collection to bound first.
Measurement only. Nothing about what is stored or how changes here.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>