Abstract This paper presents Cathedral OS, a governance, verification, and execution architecture for long lived AI and autonomous systems. The framework integrates goal integrity mechanisms, typed execution boundaries, constitutional enforcement, replay-verifiable state transitions, and immutable audit infrastructure into a unified system architecture. Rather than focusing exclusively on alignment or optimization, Cathedral OS emphasizes reproducibility, traceability, and independent verification. System behavior is represented as a sequence of admissible state transitions recorded in an append-only execution ledger and validated through deterministic replay. The architecture supports both institutional deployment configurations and autonomous operating configurations through explicit governance policies. We describe the architectural components, threat model, verification mechanisms, implementation status, and future validation