TSUNAGI

TSUNAGI is a deterministic Cardano node implementation written in Zig, designed to provide the Cardano ecosystem with an independent, production-grade node architecture that prioritizes correctness, operator observability, and modular experimentation. The system introduces a layered ledger pipeline that separates CBOR delta extraction, deterministic state application, undo management, and persistent storage into independently testable modules. A runtime shadow verification methodology validates the extracted pipeline against the proven inline implementation by comparing state transitions on every block received from the live network. Persistent UTxO storage through LMDB operates in three graduated modes — memory-only, LMDB-truth with automatic fallback, and LMDB-native — with a preflight coverage diagnostic that quantifies per-block store health. Four named observability subsystems — KAGAMI, YAMORI, TATE, and KURA — embed health evaluation, fragment defense, and automated stabilization directly in the node binary, enabling the node to explain its own health rather than requiring external diagnostic inference. Experimental validation on the Cardano preview network has produced zero shadow parity mismatches, zero apply errors, and zero rollback errors across all sessions, establishing semantic equivalence between the extracted pipeline and the proven implementation for the class of transitions observed.