[
  {
    "name": "dns_nxdomain",
    "evidence": {"dns_rcode": "NXDOMAIN", "connect_attempted": false},
    "expected_stage": "DNS_RESPONSE",
    "excluded": ["TCP_CONNECT_TIMEOUT_AS_FIRST_FAILURE"]
  },
  {
    "name": "connect_timeout",
    "evidence": {"dns_addresses": ["192.0.2.20"], "syn_sent": 3, "syn_ack_seen": false, "tls_started": false},
    "expected_stage": "CONNECT_PATH",
    "excluded": ["DNS_NO_ADDRESS"]
  },
  {
    "name": "tls_identity",
    "evidence": {"tcp_established": true, "tls_error": "certificate hostname mismatch", "http_bytes_seen": false},
    "expected_stage": "TLS_IDENTITY",
    "excluded": ["HTTP_STATUS_FAILURE"]
  },
  {
    "name": "slow_first_byte",
    "evidence": {"dns_ms": 4, "connect_ms": 8, "tls_ms": 12, "first_byte_ms": 2410, "proxy_upstream_ms": 2380},
    "expected_stage": "APPLICATION_OR_UPSTREAM",
    "excluded": ["DNS_OR_HANDSHAKE_DOMINATES"]
  }
]