INV-25 makes the GSM8K lesson structural: no capability claim is valid unless
its gold is computed by a procedure sharing no code with the system under test.
Three meaningfully-failing checks (proven able to fail): 25a oracle imports no
SUT module (AST); 25b every committed deductive gold is reproduced by the
independent oracle AND matched by the engine; 25c an unsound engine disagrees
on committed cases.
SHA-pin the deductive lane (deductive_logic_v1, dev+holdout+external 716/716,
wrong=0, refused=0) via a deterministic --report writer + run_as_module (the
lane dir's local generate.py shadows the package in script mode) + CLAIMS regen.
Fix drift the review surfaced: contract.md + pivot doc claimed an 8,000/7,340
fuzz and an 'external mirror' -> corrected to the real gated 3,000-case fuzz
(2,796 definite) and 'hand-authored, NOT a published-benchmark mirror'; pivot
doc GSM8K holdout 0->5 (all 5 are R1 reconstruction; composer scored 0).
Validated: smoke 78, deductive 23, proof 29, invariants 44, lane-sha+claims 9.
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