Fluids

The fluids block gates a fluid by its registry id:

{
  "fluids": [
    "minecraft:lava",
    {
      "id": "minecraft:water",
      "unlock_actions": ["pickup"]
    }
  ]
}

What is gated is the fluid, but what is recognised is the container. The mod asks every item stack what it is carrying rather than what it is, so a single minecraft:lava entry covers the vanilla bucket, every modded bucket, and every filled tank item in the pack — without one item id appearing in the stage file.

In the editor

The Fluids tab, with a picker over every fluid in the pack. Each row carries a [Recipes: N] badge saying how many recipes that entry would reach — worth a look before adding one, since that number is frequently larger than people expect.

The seven actions below are set the same way item entries work — right-click the row, then Lock Actions.

The seven actions

A fluid's action vocabulary is shorter than an item's, and has one action items do not have:

use · place · pickup · recipe · ingredient · loot · icon

equip, attack, break and gui are not offered — a fluid is not worn, not swung, not mined, and opens no GUI of its own.

recipe and ingredient are different things, and both are on by default

recipe gates the recipes that produce the fluid. ingredient gates the ones that consume it. An entry without unlock_actions locks all seven, so gating minecraft:water takes every recipe that touches water out of the pack — in a large modpack that is a four-digit number of recipes.

This is the single most common surprise with fluid locks. Narrow the entry with unlock_actions if that is not what you meant.

It also answers a question that otherwise reads as a bug: recipes disappear that nobody listed. Gating a fluid removes the recipes touching it from crafting and from the recipe browser, including recipes inside other mods' machines.

The [Recipes: N] badge the editor shows on a fluid row exists so the reach of an entry is visible before the decision rather than after it. The index behind that number is only built when a fluid is actually gated or the editor is open, so a row with no badge means either "none" or "not counted yet" — open the fluid tab once and it settles.

Three deliberate limits

There are no NBT criteria for fluids. Of the four places the mod is asked about a fluid, only the container item could ever supply one. A fluid block in the world and an entry in the recipe browser carry nothing to match against, so a criterion would have done nothing on the two surfaces a pack author checks first.

Name and tooltip overrides reach the container, not the fluid. A foreign tank's own GUI, and Jade's tank readout, keep showing the real name.

Pumps, pipes and placed tanks are not gated. A player who already has lava in a tank can keep moving it. Gating that would mean taking the fluid interface away from other mods' tanks, which crashes inside foreign code and cannot be caught from outside. In practice it rarely shows, because without recipes and without buckets nothing reaches the first tank. Fluids already lying in the world also keep flowing — a lock governs what a player does, not what the world contains.

Global or individual

Both, because a fluid is only ever asked about with a player at hand. The exception is the recipe side: on an individual stage it reaches only the stations that know who is crafting, exactly as recipes does. Furnaces, hoppers, autocrafters and most modded machines answer globally or not at all, and the mod writes a warning into the load report when an individual stage asks for something they cannot answer.

The message players get

Taking a locked fluid out of the world produces the fluidLocked message, which a pack can override under [lock_messages].

See also

• Unlock Actions — the item vocabulary this one parallels.
• Recipes — where the recipe and ingredient actions land.
• Mod Compatibility — how far a fluid lock reaches into other mods.
• Complete Examples