Use a purely linear network (no ReLU) for the completeness axiom test. IG on linear functions is mathematically exact, so the test is deterministic regardless of random weight initialization. Tighten tolerance from 20% to 1% (f32 rounding only). Keep ReLU network in the basic test for non-linear verification. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>