Engagement record field documenting negative entropy quarters. Record: quarter, perimeter, entropy delta, cause hypothesis, corrective action, outcome. Use for: contested posture visibility, pattern detection (repeated forfeitures = structural gap), causal modeling training data. Implement in CC-DATA-01 schema. Update quarterly during engagement. Forfeiture log prevents aggregate metrics from masking problems. Enables: root cause analysis, maintenance protocol refinement, predictive forfeiture modeling. Every engagement’s log contributes to causal dataset. Makes invisible problem visible in structured format.