The old carry-over (weight *= 0.7 per engram_activate call) was call-rate-
dependent — carried context died in seconds under rapid curiosity scans and
lingered for hours under quiet loops — and a decayed scalar cannot represent
access frequency at all.
Now: k=10 access-timestamp ring + Petrov (2006) closed-form tail, d=0.5.
WM promotion and engram_strengthen record presentations; carry-over evicts
at base-level tau=-3.0 (Soar forgetting, ~403s single-touch) and shapes the
weight held at promotion (wm_anchor) with the ACT-R retrieval logistic
(s=0.4) — a pure function of wall-clock time, idempotent per call.
Persisted as access_ts/wm_anchor in snapshots; legacy nodes fall back to
the optimized form ln(n/(1-d)) - d*ln(L). base_level exposed in both node
serializers for observability.
Backing spec: 2026-07-21 integration brief (bl-b17facdd). Verified live:
carried weight ~anchor seconds after two disjoint activations (old code:
0.49x); frequency-hot nodes hold B=1.9 vs -0.14 single-touch.
will.anderson
409ec99397