The tamper-evident Decision Ledger is live. Historical integrity is validated against an internal hash chain, not an independent third-party auditor.

The Decision Ledger is append-only and hash-chained. Each record stores previous_hash and record_hash. Altering history invalidates chain verification. The first system record, DR-D-20260831-0001, records No Action: no verified structural event meets intervention threshold. Public verification language is TAMPER-EVIDENT LEDGER / INTERNAL CHAIN VERIFIED. The system does not claim independent verification until an independent verifier exists. VERIFY LEDGER recomputes the chain. It does not silently repair broken history.