dav1d's review (RESPONSE_1 + RESPONSE_2) returned 2026-05-11. This
lands the Tier-1 items — everything that doesn't change numeric
outputs or invalidate the KAT discipline. The Tier-2 B1 conservative-
envelope (v2 calculator) is a separate decision and stays a closure
blocker.
Calculator (bench/scripts/t3_bound_calculator.py):
- Recommendation wording: "M2's single-window guarantee is broken"
→ "this conservative bound CANNOT CERTIFY M2's residual". An upper
bound exceeding 256 bits means we cannot certify, NOT that the
adversary can steer 256 bits — the prior wording overclaimed.
- New structured output fields: b1_model ("effective_control_v1"),
certification_status ∈ {CERTIFIED_BY_BOUND, NOT_CERTIFIED_BY_BOUND},
certification_threshold_bits (256), model_assumptions[]. Callers
read a machine-readable status, not just prose.
- Input validation hardening: _require_finite_float / _require_positive_int
helpers reject bools (isinstance(True, int) is True in Python — a
real leak risk for a security calculator) and NaN / ±inf for every
numeric input and constant.
- gradient_fraction = 0 now accepted (no T2 surface; B1 = 0; T3's
LR + batch-order channels still contribute) — improves component
isolation. CLI help + module docstring updated accordingly.
- Numeric outputs UNCHANGED: baseline still 625.8716 / 292.4813 /
300.0 / 33.3904; b1_model stays effective_control_v1; KAT discipline
intact.
Tests (tests/test_t3_bound_calculator.py, 53 → 75):
- Hard-coded cwd="/home/fox/git/arborist" → pathlib.Path(__file__).
resolve().parents[1] so the suite runs on any checkout.
- New: test_gradient_fraction_zero_accepted, test_bool_rejected_for_int_fields,
test_bool_rejected_for_float_fields, test_nonfinite_numbers_rejected,
test_output_carries_b1_model_and_certification_fields,
test_certification_status_certified_below_threshold.
- test_recommendation_exceeds_sha256 now also asserts "CANNOT CERTIFY"
+ certification_status == NOT_CERTIFIED_BY_BOUND.
Doc (docs/soft-hash-channel-t3-bound.md):
- §0 reworked into a reviewer brief recording dav1d's findings
(§2 accepted, §4 accepted, §5 accepted as model-bound, §3 = closure
blocker, wording/validation = applied).
- New §3.1: the B1-double-g issue spelled out — effective_control_v1
vs fraction_channels vs aggregate_bias vs max_envelope, with the
baseline-spread table (292 / 1730 / 5850 / 5850 bits); v2 path
described.
- §5: "B3 is a model-bound, not a directly-quoted theorem" note.
- §10: items 1-2 are now the closure blockers (B1 envelope v2; active
KAT fixture); items 3-7 are tightening paths (#000043). New §10.1
records what the 2026-05-11 hardening pass already landed.
- §11: calculator-output example updated to show the new fields +
corrected recommendation wording.
- §12: references add the dav1d review + clarify Bottou-Bousquet
"inspires" (not "underlies") the §5 model-bound.
Status (#000036 ticket + TICKETS.md row): review-returned + Tier-1-
applied; closure blockers = B1 v2 envelope (awaits fox go/no-go) +
active KAT fixture. R2's architectural integrations (Merkle audit-
event commitment, SQD canonicalization, CTI clause-lattice, 5F
trigger, ForkScore security-risk) noted as out-of-scope (separate
tickets if wanted).
AUTOCOUNT markers in docs/calculator-test-patterns.md +
docs/warrant-substrate-cookbook.md bumped 53 → 75.
Full suite: 2264 passed, 28 skipped.
russell@unturf.com
da62f8047c