{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "additionalProperties": false,
  "required": [ "$sort", "by(x)" ],
  "properties": {
    "$sort": {
      "type": "array",
      "items": {
        "type": "integer",
        "minimum": 0
      }
    },
    "by(x)": {
      "type": "string"
    }
  }
}