---
title: Biome & Loot Modifiers
hide_meta: true
---

Field Guide uses datapacks to modify which biomes and loot drops appear on an entry's page.
You can target base entities, or specific variants by appending `#variant_id` to the entry identifier.

* **Biome Modifiers:** `data/<namespace>/fieldguide/biome_modifiers/<filename>.json`
* **Loot Modifiers:** `data/<namespace>/fieldguide/loot_modifiers/<filename>.json`

**Example: Targeting a Base Entry**
```json
{
  "additions": [
    {
      "entry": "minecraft:cow",
      "value": "minecraft:milk_bucket"
    }
  ]
}
```

**Example: Disambiguating Entry Type**

If a mod registers both a block and an entity with the same ID, you can use a type prefix (`entity:`, `block:`, or `item:`) to target one specifically.

```json
{
  "additions": [
    {
      "entry": "entity:minecraft:zombie",
      "value": "minecraft:rotten_flesh"
    }
  ]
}
```

**Example: Targeting Specific Variants (Biome Modifiers)**

If you want to isolate specific biomes to a specific variant (like a Desert Villager only showing the Desert biome), use the `#` symbol:

```json
{
  "additions": [
    {
      "entry": "minecraft:villager#desert",
      "value": "minecraft:desert"
    }
  ],
  "removals": [
    {
      "entry": "minecraft:villager#desert",
      "value": "minecraft:plains"
    }
  ]
}
```

**Example: Targeting Specific Variants (Loot Modifiers)**

You can also target specific variants for loot additions and removals. For example, adding Red Wool and removing White Wool specifically for Red Sheep, or adding Cactus drops to Desert Villagers:

```json
{
  "additions": [
    {
      "entry": "minecraft:sheep#red",
      "value": "minecraft:red_wool"
    },
    {
      "entry": "minecraft:villager#desert",
      "value": "minecraft:cactus"
    }
  ],
  "removals": [
    {
      "entry": "minecraft:sheep#red",
      "value": "minecraft:white_wool"
    }
  ]
}
```