{
  "schema": "pg36-ch22-endpoint-contract-v1",
  "logical_service": "pg36_shop",
  "sandbox_database": "test",
  "endpoints": [
    {
      "name": "primary",
      "port": 5433,
      "client_semantics": "pooled read-write service",
      "selector_semantics": "Patroni /primary",
      "destination": "PgBouncer 6432 on current primary",
      "pool_mode": "transaction",
      "allowed_work": [
        "short OLTP transactions",
        "protocol-level prepared statements when the exact version matrix is proven"
      ],
      "forbidden_assumptions": [
        "one client session owns one PostgreSQL backend",
        "SQL session state survives transaction boundaries"
      ]
    },
    {
      "name": "replica",
      "port": 5434,
      "client_semantics": "pooled read-only, replica-preferred service",
      "selector_semantics": "Patroni /read-only with primary/offline as backups",
      "destination": "PgBouncer 6432 on eligible replicas",
      "pool_mode": "transaction",
      "allowed_work": [
        "staleness-tolerant read-only transactions"
      ],
      "forbidden_assumptions": [
        "read-your-writes",
        "bounded staleness without an explicit LSN protocol",
        "a replica is always selected under degradation"
      ]
    },
    {
      "name": "default",
      "port": 5436,
      "client_semantics": "direct primary service",
      "selector_semantics": "Patroni /primary",
      "destination": "PostgreSQL 5432 on current primary",
      "pool_mode": "none",
      "allowed_work": [
        "administration",
        "ETL or migration work that requires a stable backend",
        "CDC or session-sensitive tooling after separate review"
      ],
      "forbidden_assumptions": [
        "unlimited direct connections",
        "safe application default"
      ]
    },
    {
      "name": "offline",
      "port": 5438,
      "client_semantics": "direct isolated analytic replica service",
      "selector_semantics": "declared offline replica, normal replica fallback",
      "destination": "PostgreSQL 5432",
      "pool_mode": "none",
      "allowed_work": [
        "reviewed OLAP and ETL reads"
      ],
      "forbidden_assumptions": [
        "fresh data",
        "write availability",
        "no effect on replay"
      ]
    }
  ]
}