{
  "name": "ncp-alpha19-runtime-hardening",
  "version": "0.12.0",
  "spec_ref": "spec/NPS-1-NCP.md §7.7",
  "description": "Deterministic keepalive, close, QUIC early-data/migration, and two-layer backpressure decisions. Times are monotonic milliseconds from an established session origin.",
  "vectors": [
    {
      "id": "ncp.alpha19.runtime.001",
      "requirement": "NCP-P19-01",
      "description": "The lower non-zero offer wins after applying the one-second floor.",
      "kind": "positive",
      "input": {"client_ping_ms": 500, "server_ping_ms": 4000},
      "expected": {"keepalive_enabled": true, "effective_interval_ms": 1000}
    },
    {
      "id": "ncp.alpha19.runtime.002",
      "requirement": "NCP-P19-01",
      "description": "Two zero offers disable application keepalive.",
      "kind": "positive",
      "input": {"client_ping_ms": 0, "server_ping_ms": 0},
      "expected": {"keepalive_enabled": false, "effective_interval_ms": null}
    },
    {
      "id": "ncp.alpha19.runtime.003",
      "requirement": "NCP-P19-02",
      "description": "Only a complete valid inbound frame resets the dead-peer clock.",
      "kind": "positive",
      "input": {"last_valid_inbound_ms": 0, "events": [{"at_ms": 900, "event": "local_send"}, {"at_ms": 1200, "event": "partial_header"}, {"at_ms": 1400, "event": "valid_inbound_frame"}]},
      "expected": {"last_valid_inbound_ms": 1400}
    },
    {
      "id": "ncp.alpha19.runtime.004",
      "requirement": "NCP-P19-03",
      "description": "Idle send time enqueues one payload-free probe and ordinary traffic replaces it.",
      "kind": "positive",
      "input": {"effective_interval_ms": 2000, "last_application_send_ms": 0, "evaluate_at_ms": 2000, "queued_probe_count": 0},
      "expected": {"enqueue": {"frame": "0x07", "payload_length": 0}, "queued_probe_count": 1}
    },
    {
      "id": "ncp.alpha19.runtime.005",
      "requirement": "NCP-P19-04",
      "description": "The threshold produces one timeout, cancels streams, and closes within 500 ms.",
      "kind": "negative",
      "input": {"effective_interval_ms": 2000, "last_valid_inbound_ms": 0, "evaluate_at_ms": 6000, "active_streams": 3},
      "expected": {"state": "closing", "error": "NCP-KEEPALIVE-TIMEOUT", "error_count": 1, "cancelled_streams": 3, "close_by_ms": 6500, "allow_later_application_frames": false}
    },
    {
      "id": "ncp.alpha19.runtime.006",
      "requirement": "NCP-P19-05",
      "description": "A payload-bearing Nop is invalid and does not refresh liveness.",
      "kind": "negative",
      "input": {"frame": "0x07", "payload_length": 1, "last_valid_inbound_ms": 20, "received_at_ms": 100},
      "expected": {"accepted": false, "error": "NCP-FRAME-PAYLOAD-TOO-LARGE", "last_valid_inbound_ms": 20}
    },
    {
      "id": "ncp.alpha19.runtime.007",
      "requirement": "NCP-P19-06",
      "description": "NPS application data in QUIC 0-RTT is rejected without consuming the post-handshake retry.",
      "kind": "negative",
      "input": {"carrier": "quic", "handshake_confirmed": false, "early_data": {"frame": "0x06"}},
      "expected": {"accepted": false, "error": "NCP-EARLY-DATA-REJECTED", "retry_after_confirmation": true}
    },
    {
      "id": "ncp.alpha19.runtime.008",
      "requirement": "NCP-P19-07,NCP-P19-08",
      "description": "Authenticated migration preserves identity and carrier credit cannot bypass an exhausted NCP window.",
      "kind": "positive",
      "input": {"handshake_confirmed": true, "bound_nid": "urn:nps:agent:example:a", "migrated_nid": "urn:nps:agent:example:a", "carrier_credit_bytes": 65536, "ncp_window_cgn": 0, "frame": "0x03"},
      "expected": {"migration_allowed": true, "session_preserved": true, "send_allowed": false, "reason": "ncp_window_exhausted"}
    }
  ]
}