The consumer report (portfolio-optimiser, S7 SS 2) found that a mandate-shaped
cost question withheld the corpus's one priced table under `below_k`. Measured
here, on a bundle proven byte-identical to a fresh HEAD rebuild:
- The mechanism is a VOCABULARY gap, not a `k` defect: two of three ranking
signals are exactly 0.0 and the concept is candidate 249 of 269.
- The k-sweep buys nothing: k in {8,12,16,24,32,64,128} all withhold it, at
+9.5 % tokens. It also found a regression -- for the question that WORKS,
k >= 16 EVICTS the gold concept, because one 67 838 B excerpt is 56.5 % of
the budget and the knapsack maximises a sum.
- Two proposed rules were falsified BEFORE any code: number/table density ranks
the priced table 178/165/46 of 269 (the form is unfilled, so it is
number-poor), and per-document spread puts its document 30th of 35.
Built instead, behind `--cost-vocabulary` (default OFF, DEFAULT byte-identical):
one declared cost/price/quantity vocabulary family that bridges a question and a
document naming money with different words. It moves the concept from candidate
rank 249 to 10 -- and does NOT close the blind spot: the budget still refuses
it, which is now a separately measured second lock.
Seven RED tests first; six mutations of the rule, six red (two survived the
first version of the tests and the tests were strengthened). Control: a question
with no cost term produces a byte-identical payload with the flag on, at every
k, on the real corpus. Known-positive: 164 987 B / 40 425 o200k tokens, equal to
the published pair.
Report: docs/2026-09-08-blindsone-below-k-k2.md
Suite 1268 green, mypy --strict clean over 28 files, both goldens unchanged.
Co-Authored-By: Claude <claude-opus-5>
