{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "Token-level POS, lemma and morphology annotation",
  "type": "object",
  "required": ["sentence_id", "language", "tokens"],
  "additionalProperties": false,
  "properties": {
    "sentence_id": {
      "type": "string"
    },
    "language": {
      "type": "string"
    },
    "tokens": {
      "type": "array",
      "items": {
        "type": "object",
        "required": ["surface", "lemma", "upos", "features", "confidence", "comment"],
        "additionalProperties": false,
        "properties": {
          "surface": {
            "type": "string"
          },
          "lemma": {
            "type": ["string", "null"]
          },
          "upos": {
            "type": "string",
            "enum": [
              "ADJ",
              "ADP",
              "ADV",
              "AUX",
              "CCONJ",
              "DET",
              "INTJ",
              "NOUN",
              "NUM",
              "PART",
              "PRON",
              "PROPN",
              "PUNCT",
              "SCONJ",
              "SYM",
              "VERB",
              "X"
            ]
          },
          "features": {
            "type": "object",
            "additionalProperties": false,
            "properties": {
              "Case": {
                "type": ["string", "null"]
              },
              "Number": {
                "type": ["string", "null"]
              },
              "Gender": {
                "type": ["string", "null"]
              },
              "Person": {
                "type": ["string", "null"]
              },
              "Tense": {
                "type": ["string", "null"]
              },
              "Mood": {
                "type": ["string", "null"]
              },
              "Voice": {
                "type": ["string", "null"]
              }
            }
          },
          "confidence": {
            "type": "string",
            "enum": ["low", "medium", "high"]
          },
          "comment": {
            "type": ["string", "null"]
          }
        }
      }
    }
  }
}