{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "subject": {
      "type": "string",
      "enum": [
        "link",
        "target",
        "citation"
      ],
      "description": "The subject value; allowed values and bounds are specified in this schema."
    },
    "observationId": {
      "type": "string",
      "minLength": 1,
      "maxLength": 200,
      "description": "ID of a saved observation; this does not fetch a new publisher page."
    }
  },
  "required": [
    "subject",
    "observationId"
  ],
  "additionalProperties": false
}