{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://colliery-io.github.io/cloacina/schemas/ws/delivery-client-message.schema.json",
  "title": "Substrate delivery — recipient → server frames",
  "description": "Client side of the substrate delivery envelope (CLOACI-S-0012). JSON text frames. The server validates `protocol_version` on `hello` and closes with code 4426 when it doesn't speak the requested version; malformed frames close with 4400.",
  "oneOf": [
    {
      "title": "hello",
      "description": "Optional connect-time handshake declaring the client's protocol version. `since_id` is an advisory cursor hint; v1 ignores it (the server resets delivered→pending and replays via the relay).",
      "type": "object",
      "properties": {
        "type": { "const": "hello" },
        "protocol_version": { "type": "integer", "minimum": 1 },
        "since_id": { "type": ["integer", "null"] }
      },
      "required": ["type", "protocol_version", "since_id"],
      "additionalProperties": false
    },
    {
      "title": "ack",
      "description": "Recipient confirms it has processed row `id`. Idempotent — re-acking an acked or unknown row is a no-op.",
      "type": "object",
      "properties": {
        "type": { "const": "ack" },
        "protocol_version": { "type": "integer", "minimum": 1 },
        "id": { "type": "integer" }
      },
      "required": ["type", "protocol_version", "id"],
      "additionalProperties": false
    }
  ]
}