Make the ambiguous-band speaker-evidence case prove it lands in the else branch by asserting its preconditions against imported calibration constants, so a future recalibration that moves the case out of that band fails loudly instead of silently dropping coverage. Reject non-finite tolerance-managed values. NaN and infinities no longer evade comparison; abs(nan - expected) > tolerance is false, so a committed nan previously passed as agreement. Unparseable row tokens now produce a located diagnostic instead of a bare ValueError. Remove the unused ArtifactDescriptor.path field and drop bare production numerals from tolerance rationale comments so the text cannot go stale against recalibration.