{
  "yaml.schemas": {
    "test.schema.json": "test.yaml"
  }
}

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://example.com/test.schema.json",
  "title": "Test",
  "description": "Bug Test",
  "type": "object",
  "properties": {
    "tag": {
      "$ref": "#/definitions/tags"
    }
  },
  "definitions": {
    "tag": {
      "type": "object",
      "properties": {
        "category": {
          "type": "string",
          "enum": ["A", "B"]
        },
        "name": {
          "oneOf": [
            { "title": "T1", "const": "T1" },
            { "title": "T2", "const": "T2" },
            { "title": "T3", "const": "T3" }
          ]
        }
      },
      "additionalProperties": false,
      "required": ["category", "name"]
    },
    "tags": {
      "type": "array",
      "items": {
        "$ref": "#/definitions/tag"
      },
      "uniqueItems": true
    }
  }
}