Why Isn't the Anvil Swap Button Glowing? Understanding When Swapping Helps

The swap button only glows when reversing your items would make the anvil operation cheaper. A button that stays dark isn't broken.

What the Glow Means

In Minecraft's anvil code, the cost depends partly on the enchantments being added from the right-slot item. Because of that, putting a high-level enchantment in the first slot and a cheaper one in the second can cost more than the reverse. The mod compares the two arrangements and lights the button only when the reversed order is cheaper.

Common Reasons for No Glow

• Your order is already the cheapest. Nothing to fix.
• Both orders cost the same. This often happens with very similar items, so swapping gains nothing.
• The swap wouldn't give a valid result. For example, the reversed arrangement may not combine the same way, so the mod leaves the button unlit.
• A slot is empty. The button has nothing to compare until both slots hold items.

Quick Check

1. Put both items in the anvil.

2. Look at the cost of the result.

3. If the button is dark, proceed. You're already paying the lowest price for this combination.