Debugging LootTweaker Scripts That Do Nothing

Check the Log First

When a LootTweaker script fails, the game usually logs a parse or runtime error during /reload. Open logs/latest.log and search for loottweaker or crafttweaker. A missing import, a wrong resource location, or a malformed number will all show up there. Fix the first error before looking at others, since one bad line can abort the whole file.

Validate Table Names

A silent failure almost always means the table name is wrong. Resource locations are case-sensitive and use a namespace prefix. minecraft:entities/zombie is correct; Zombie or entity/zombie is not. Dump the loaded tables and compare your string character by character.

Confirm the Script Is Loaded

Scripts must sit in the correct scripts folder for the instance. If you have multiple instances or a modpack with its own script directory, your file may be in the wrong place. Check that the file ends in .zs and that no other script throws an error earlier in alphabetical order.

Watch for Overrides

Another datapack or mod can replace the same loot table after your script runs. If your additions vanish but no error appears, test in a minimal world with only LootTweaker and CraftTweaker enabled. If it works there, a conflicting pack is the culprit — adjust load order or merge your changes into the overriding file.