base_schema_id.json

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://example.com/schemas/lookup-user",
  "$ref": "#/$defs/LookupUser",
  "$defs": {
    "LookupName": {
      "properties": {
        "first": {
          "type": "string"
        },
        "surname": {
          "type": "string"
        }
      },
      "additionalProperties": false,
      "type": "object",
      "required": [
        "first",
        "surname"
      ]
    },
    "LookupUser": {
      "properties": {
        "name": {
          "$ref": "#/$defs/LookupName"
        },
        "alias": {
          "type": "string"
        }
      },
      "additionalProperties": false,
      "type": "object",
      "required": [
        "name"
      ]
    }
  }
}