minecraft-assets/assets/minecraft/advancements/nether/create_full_beacon.json

{
    "display": {
        "icon": {
            "item": "minecraft:beacon"
        },
        "title": "Beaconator",
        "description": "Bring a beacon to full power",
        "frame": "goal"
    },
    "parent": "minecraft:nether/create_beacon",
    "criteria": {
        "beacon": {
            "trigger": "minecraft:construct_beacon",
            "conditions": {
                "level": 4
            }
        }
    }
}