{
  "type": "advancement_reward",
  "pools": [
    {
      "rolls": 1,
      "entries": [
        {
          "type": "item",
          "name": "patchouli:guide_book",
          "functions": [
            {
              "function": "set_nbt",
              "tag": "{\"patchouli:book\": \"vrcrawler\"}"
            }
          ]
        }
      ]
    }
  ]
}