I haven't personally tried such a stunt, but I'd bet it's possible to do that with JSON Schema, too, if the schema resolver tolerates the same self-references style in `$schema`. My experience with the tooling is "lol, yeah right" but shrug seems reasonable

    {
      "$schema": "#/$theSchema",
      "$theSchema": {
        "$schema": "https://json-schema.org/draft/2020-12/schema",
        "$id": "MySchema",
        "type": "object",
        "properties": {
          "productId": {
            "description": "The unique identifier for a product",
            "type": "integer"
          },
          "productName": {
            "description": "Name of the product",
            "type": "string"
          },
          "price": {
            "description": "The price of the product",
            "type": "number",
            "exclusiveMinimum": 0
          }
        }
      },
      "productId": 1,
      "productName": "An ice sculpture",
      "price": 12.50
    }