{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://offeringprotocol.org/schemas/sort-key.schema.json",
  "title": "ODP Sort Key",
  "type": "object",
  "required": [
    "filter_id",
    "direction",
    "missing"
  ],
  "properties": {
    "filter_id": {
      "$ref": "capability-identifier.schema.json"
    },
    "direction": {
      "enum": [
        "ascending",
        "descending"
      ]
    },
    "missing": {
      "enum": [
        "first",
        "last"
      ]
    }
  }
}