Tough Mail is a lightweight standalone armor-lining mod for Forge 1.20.1, inspired by the original ChainMailed mod.

It lets you reinforce armor by installing a mail insert into it. By default, vanilla chainmail armor can be used as mail, but valid mail sources and blocked target armor pieces can be configured.

How it works:

Hold the armor piece you want to reinforce in your main hand, hold a valid mail source in your off hand, then right-click. The mail source will be consumed and stored inside the target armor.

A reinforced armor piece gains bonuses based on the inserted mail’s armor value:

Extra armor: half of the mail’s armor value by default
Extra armor toughness: equal to the mail’s armor value by default

For example, a mail insert with 4 armor value gives the reinforced armor:

+2 armor
+4 armor toughness

These values are configurable. Armor and armor toughness bonuses can use either fixed values or multiplier-based values.

Inherited attributes:

Tough Mail can also inherit basic item attributes from the inserted mail piece.

Armor and armor toughness are handled by Tough Mail’s own bonus rules. If the inserted mail piece already has base armor toughness, that original toughness is also inherited. Other basic attributes, such as knockback resistance or other item attribute modifiers, can also be inherited when they are exposed through the armor item’s normal attribute modifiers.

Tough Mail does not inherit enchantments, scripted abilities, or complex set bonuses. Enchanted armor pieces cannot be used as mail inserts.

Removing mail:

Sneak and right-click with a reinforced armor piece in your main hand and an empty off hand to remove the installed mail insert. The inserted mail piece will be restored to your off hand. If your off hand is occupied, removal will fail safely instead of deleting the item.

Configuration:

The mod generates a config file at:

config/toughmail-common.toml

You can configure:

Which armor items count as valid mail sources
Which armor items cannot receive mail inserts
How much armor mail inserts provide
How much armor toughness mail inserts provide

Tooltip:

Reinforced armor shows which mail piece is installed inside it. Hold Shift while viewing the tooltip to see the inherited attribute details.

Compatibility notes:

Tough Mail is designed as a standalone replacement-style mod and should not be installed together with the original ChainMailed mod.

Tough Mail is required on both client and server.

It keeps compatibility with the old reinforcedChain NBT key, so armor previously reinforced by ChainMailed-style systems may still be recognized when possible.

Credits:

This mod is inspired by ChainMailed by AstianBK. However, Tough Mail is not an official continuation or official fork unless stated otherwise. It is a separate open-source implementation made for configurable armor lining behavior.