Consistency Model Selector
Choose the correct consistency model (linearizability, causal consistency, or eventual consistency) for each operation in a distributed system, and select the matching implementation mechanism. Use when designing a new distributed data system, deciding whether ZooKeeper or etcd is needed for coordination, evaluating whether two-phase commit is appropriate for cross-node transactions, debugging correctness violations (stale reads, split-brain, uniqueness constraint failures), or distinguishing linearizability from serializability. Also use when applying the CAP theorem correctly (beyond the "pick 2 of 3" oversimplification), selecting total order broadcast as a consensus primitive, evaluating 2PC failure modes and lock-holding cost, or assessing whether causal consistency is sufficient in place of linearizability. Produces a per-operation consistency recommendation with replication mechanism, ordering guarantee, and — when consensus is needed — protocol selection (Raft, Zab, Paxos) with documented failure modes. Does not cover replication topology or failure recovery strategy (see replication-strategy-selector, distributed-failure-analyzer).
