Component Rarity Control (1.21.1)

New in Ver.13 — 1.21.1+ exclusive

Difference from 1.20.1: In Minecraft 1.21.1 NeoForge, custom data is no longer stored directly on the item's top-level NBT tag. Instead, it is wrapped in the DataComponents.CUSTOM_DATA component. Therefore, 1.21.1 uses DataComponent Control instead of the old NBT tag control.

Items with raritycore data stored in DataComponents.CUSTOM_DATA can directly control their rarity display. Controlled by server.json → enableComponentRarityControl (off by default).

Enabling

In config/raritycore/server.json:

{
  "enableComponentRarityControl": true
}

Then /raritycore reload.

Data Storage (1.21.1)

ItemStack
└── DataComponents.CUSTOM_DATA (CompoundTag)
    └── "raritycore" (CompoundTag)
        ├── Level (int)          — Rarity level
        ├── Color (string)       — RGB color, e.g. "#FFAA00"
        ├── Tooltips (bool)      — Show tooltip
        ├── Renderer (bool)      — Render border
        ├── NameColor (bool)     — Recolor name
        └── TextureBorder (string) — Texture path

All fields are optional — missing fields fall back to regular config.

Examples

/give command (1.21.1 component syntax)

/give @p minecraft:diamond_sword[minecraft:custom_data={raritycore:{Level:6,Color:"#FF6666"}}]

Java code

import net.minecraft.core.component.DataComponents;
import net.minecraft.nbt.CompoundTag;
import net.minecraft.world.item.ItemStack;

CompoundTag customData = itemStack.getOrDefault(DataComponents.CUSTOM_DATA, CompoundTag.EMPTY).copy();
CompoundTag rarityCoreTag = new CompoundTag();
rarityCoreTag.putInt("Level", 6);
rarityCoreTag.putString("Color", "#FF6666");
rarityCoreTag.putBoolean("Tooltips", true);
rarityCoreTag.putBoolean("Renderer", true);
rarityCoreTag.putBoolean("NameColor", true);
customData.put("raritycore", rarityCoreTag);
itemStack.set(DataComponents.CUSTOM_DATA, customData);

KubeJS

PlayerEvents.tick(event => {
    let stack = event.player.mainHandItem;
    if (stack.id === "minecraft:diamond_sword") {
        let nbt = stack.nbt || {};
        nbt.raritycore = { Level: 6, Color: "#FF6666" };
        stack.nbt = nbt;
    }
});

Rules

Condition	Behavior
Level not set	No effect, falls back to regular query
Level = 0	No rarity (treated as default 1)
Level > 0	Highest priority (overrides everything)
Color not set	Uses RarityClientConfig or default color
Tooltips etc. not set	Default enabled

Priority

Component control has the highest priority:

Component Control (this feature)     ← Highest
  ↓
Item Data Matching
  ↓
Apotheosis Adapter
  ↓
Iron's Spells Adapter
  ↓
ITEM_RARITY_MAP (FinalRarity.json)
  ↓
TagRarity (TagRarity.json)
  ↓
AUTO_RARITY_MAP (auto-calculated)
  ↓
Vanilla Rarity

Performance Notes

• Off by default for performance — each item stack requires CUSTOM_DATA inspection
• Uses a dedicated component cache (ComponentCacheManager) based on DataComponent hashes, preventing pollution of same-item-ID caches
• Only enable when dynamic rarity control is actually needed

Version Migration (1.20.1 → 1.21.1)

1.20.1	1.21.1
enableNbtRarityControl	enableComponentRarityControl
{raritycore:{Level:6}}	[minecraft:custom_data={raritycore:{Level:6}}]
tag.getCompound("raritycore:data")	stack.get(DataComponents.CUSTOM_DATA).copyTag().getCompound("raritycore")