The ABCI Layer

ABCI is the boundary between CometBFT and the Xian application.

In Xian, xian-abci implements the application side of that boundary and CometBFT owns consensus, networking, and block ordering.

Core Responsibilities

xian-abci handles:

• CHECK_TX style validation before mempool admission
• block execution in FINALIZE_BLOCK
• state commit and app-hash generation
• read-only queries

Important Behavior

• successful transactions emit standard ABCI events for contract events
• simulate_tx is handled in-process, not by a sidecar socket
• dashboard REST and WebSocket endpoints proxy or enrich CometBFT-facing data

Why This Boundary Matters

Consensus does not know contract semantics. CometBFT only needs a deterministic application that validates, executes, and commits the same state transitions on every validator.