# M01-L01 — Lab contract

**Build:** Build 3 replicas, append numbered transfers, compare state digests.

**Pass:** After identical ordered inputs all three hashes match; reordered inputs are rejected.

**Failure injection:** Messages arrive in different orders and replicas diverge.

**Review question:** What does replication not solve without consensus?

Status: specification; only count as executable when source and tests are present and verified.