How to Add a Custom Drop to a Mob with /cemd addhand

Prepare the item you want to drop

Hold the exact item you want the mob to drop in your main hand. This matters because /cemd addhand copies the item stack in your hand — including any NBT data such as enchantments, custom names, written book contents, or potion effects. If you want a mob to drop a named sword or a signed book, create that item first and hold it before running the command.

Run the command

Open chat and type /cemd addhand <entity-name>, replacing <entity-name> with the mob's registered entity ID (for example, the vanilla ID for a zombie or skeleton). The command registers the held item as an extra drop for that mob. You can repeat this for multiple items on the same mob — each run adds another entry to that mob's drop list.

Verify and adjust

After adding drops, check the generated configuration file to confirm the entry was written and to set its drop probability. By default a newly added drop may not be guaranteed, so open the config and adjust the chance value for that item if you want it to always drop or to drop rarely. Run /cemd reload after editing the file so the server picks up your changes without a restart. Test by killing the mob in-game and checking the drops.