Description
You open a chest and find a diamond chestplate with Protection IV. Is it better than the iron one you are wearing, and by how much? The game's tooltip only lists the new item's own numbers, so you open your inventory, hover your own chestplate, and do the sum in your head.
Where: at the bottom of the item tooltip, in your inventory, in chests, anywhere the game shows an item's tooltip.
What it does: for armor, it compares with what you wear in that slot; for weapons and tools, with what you hold in your main hand. It adds lines like these under the game's own lines:
+2 Armor, +2 Armor Toughness, +1 Knockback Resistance, +1 Attack Damage, +26 Mining Efficiency (from Efficiency V), or any other attribute the two items give (green = better for you, red = worse, gray = neither) +288 durability left (528, yours 240): durability points left on each
- Protection IV, - Mending, Protection IV (yours II): enchantments you gain, lose or change (gaining a curse is red) The header names what you compare with: "If you swap it for what you wear (Iron Chestplate)", or "If you put it on (your head slot is empty)". If nothing differs: "Same stats". It does not compare the item you already wear or hold with itself, and it adds nothing to blocks, food and other things you do not wear or fight with.
/geardiff on / /geardiff off: switch it (saved). /geardiff shift: only while Shift is held (a short hint line otherwise). /geardiff always: always. Client-side only: install it on your own game; nothing is needed on the server, and it sends nothing to the server. It only reads the two items' own data and your base attribute values, which the game already uses for its tooltips. Result: in the automated test, for each of 8 cases (diamond vs iron sword, diamond vs iron chestplate, golden helmet on an empty head, netherite vs diamond leggings, cursed leather boots vs enchanted diamond boots, an Efficiency V pickaxe vs the held sword, Fire Protection IV boots, an Aqua Affinity helmet) the test really put the item on, read the player's attribute values from the game, and the tooltip showed exactly that difference. With the mod switched off, those lines are gone (picture 1).





