ACI-040: Silent Success

Thesis

The most dangerous failure in agent-built tooling is a silent success: a run whose output matches the run that was meant, so nothing errors and no error path catches it. Find it by sweeping the source by defect class rather than rereading output, derive unaccounted outcomes as a residual, keep failures as typed values that ride the result, and never let a bypass stay silent about what it destroys. When you unmask one, budget in the same session for the failure it was storing.