{
  "kind": "capability_negotiation",
  "expect": "valid",
  "description": "unsupported with no explicit failure_class -> capability_unsupported / do_not_retry",
  "data": {
    "outcome": "unsupported",
    "expected": {
      "failure_class": "capability_unsupported",
      "retry_class": "do_not_retry"
    }
  }
}
