The pinned artifact carried verdict counts only. The runner's docstring
justified that: prose is "presentation, not decision", so the pinned bytes
"stay stable against wording-only changes; wording is covered by
tests/test_deduction_surface.py."
Measured, that justification was false. With render._display_noun sabotaged
so every clause reads "all SABOTAGE_dogs are SABOTAGE_animals":
11 lane SHA pins -> 11/11 byte-identical, blind
test_deduction_serve_lane + _license -> 20 passed, blind
tests/test_deduction_surface.py -> 41 passed, blind
(the named wording guard)
evals/grammar_roundtrip -> RED, the only witness
So CORE's user-visible output was unguarded by its own hash pins, which is
how the ratified v1b band served "all dog are mammal" for the entire arc
with wrong=0 intact.
build_report now emits surface_sha256 + per-case surfaces from the real
deduction_grounded_surface — the same call chat serving makes, so what is
hashed is what a user reads. Note build_combined_report re-projects five
named fields per split, so a field added to build_report alone never reaches
the pinned bytes; both had to change. The payload is not the report.
Surfaces are recorded, not just digested, so a moved pin shows the exact
sentence that changed in review instead of an opaque hash to go re-derive.
2,766 -> 37,280 bytes.
deduction_serve_v1 under sabotage: BEFORE byte-identical (blind)
AFTER 52370b73 vs c855d55c (RED)
Re-pinned surgically, one line, old hash recorded beside it, never --update.
Verdicts untouched: 166/166 correct, wrong=0. The hash moved because the
payload grew.
test_surface_hash_moves_when_the_renderer_is_sabotaged makes it permanent:
it corrupts the renderer, requires a digest to move, AND asserts the
aggregate counts are unchanged — proving the digest tracks PROSE rather than
smuggling in a decision change. A pin that cannot fail guards nothing.
Accepted cost: wording-only changes now move this pin. That is the intent —
a wording change IS a user-visible change and should require a deliberate
re-pin. The other 10 lanes are untouched; deduction_serve was fixed because
it is the one demonstrably serving prose to users.
[Verification]: in-worktree on CPython 3.12.13, uv sync --locked —
smoke 621 unchanged; deductive 405 (403 + 2 new);
scripts/verify_lane_shas.py 11/11 with the new pin, and 10/11 (RED on
deduction_serve_v1) under the sabotage it previously could not see.
