{
  "name": "session.hello \u2014 a client built against protocol 2.x is refused",
  "description": "Major mismatch fails loudly at connect rather than subtly at the tenth field. The GUI renders this as 'Velox needs updating'.",
  "request": {
    "jsonrpc": "2.0",
    "id": 100,
    "method": "session.hello",
    "params": {
      "clientType": "gui",
      "clientName": "velox-gui 9.9.9",
      "protocolVersion": "2.0.0"
    }
  },
  "response": {
    "jsonrpc": "2.0",
    "id": 100,
    "error": {
      "code": -32001,
      "message": "protocol major version mismatch: daemon speaks 1.x, client speaks 2.x",
      "data": {
        "expected": "$any",
        "actual": "2.0.0"
      }
    }
  },
  "assertions": [
    "the connection is closed after this reply; no method is served on a mismatched major",
    "a differing minor or patch is accepted, never refused",
    "the message is safe to show a user verbatim",
    "the version check is transport-independent; this is replayed on the Unix socket so it is not masked by -32002",
    "data.expected is the daemon's own current protocol version string (kProtocolVersion), not a bare major and not pinnable in a golden file -- the conformance compare on error payloads is on `code` only, structural elsewhere, so echoing the live version is fine"
  ],
  "transport": "uds",
  "closesConnection": true
}