Message envelope

interface WaylocateMessage {
  /** Namespace guard and protocol version. Reject anything without it. */
  waylocate: 1;
  kind: "command" | "result" | "event";
  /** Dot-namespaced, e.g. "camera.flyTo" or "selection.changed" */
  name: string;
  /** Correlation ID. Present on commands and their results; absent on events. */
  id?: string;
  payload?: unknown;
  /** Events only. Who caused this. */
  source?: "user" | "host" | "system";
}

Result messages add ok:

{ "waylocate": 1, "kind": "result", "name": "selection.setRoom", "id": "c7", "ok": true }

{ "waylocate": 1, "kind": "result", "name": "selection.setRoom", "id": "c7", "ok": false,
  "error": { "code": "REF_NOT_FOUND", "message": "No room matching 'room-999'" } }

The waylocate: 1 field is a namespace guard, not just a version number. Anything without it is dropped.