BFM-decomp/rules/G21.md

G21 -- A second, DISAGREEING oracle — on a schedule

When an oracle is structurally blind to an error class, the fix is a second independent oracle that must agree, not a better assertion in the first. From day one a standing harness runs the same question down two independent paths (matched? compiles? fleet green? scanner coverage? agent produced work? bankable?) on a schedule and fails loudly on disagreement. provenance: BFM R34 + accelerator #15; ten blockers in one session, every one caught only by a disagreement