Custom Recipe Condition

MBD2 21.1.1

A RecipeCondition answers whether a recipe may run for one RecipeLogic. It should inspect world or machine state without consuming resources or mutating the world.

Complete example

@Getter
@Setter
@NoArgsConstructor
@LDLRegister(name = "moon_phase", registry = "mbd2:recipe_condition")
public final class MoonPhaseCondition extends RecipeCondition {
    @Configurable(name = "recipe.condition.examplemod.moon_phase")
    @ConfigNumber(range = {0, 7}, type = ConfigNumber.Type.INTEGER)
    private int phase;

    public MoonPhaseCondition(int phase) {
        this.phase = Math.clamp(phase, 0, 7);
    }

    @Override
    public Component getTooltips() {
        return Component.translatable(
            "recipe.condition.examplemod.moon_phase.tooltip", phase);
    }

    @Override
    public IGuiTexture getIcon() {
        return new ItemStackTexture(Items.CLOCK);
    }

    @Override
    public boolean test(MBDRecipe recipe, RecipeLogic logic) {
        return logic.getMachine().getLevel().getMoonPhase() == phase;
    }
}

The no-argument constructor is required because the condition registry creates a fresh instance for PersistedParser. @Configurable fields become editor controls and are encoded by RecipeCondition.CODEC through the registered condition type.

Add it to recipes

builder.addCondition(new MoonPhaseCondition(0));

// Reverse is applied by MBDRecipe, not inside test().
builder.addCondition(new MoonPhaseCondition(4).setReverse(true));

For KubeJS, either expose a convenience method in your own integration or pass an instance to the existing addCondition(condition) method when the class is allowed to scripts.

Combination and reverse semantics

• test(...) returns the positive condition only. MBD2 compares the result with isReverse().
• RecipeCondition#isOr() defaults to true. Conditions with the same registered type are grouped as alternatives: at least one must pass.
• Different registered types are combined with AND.
• Override isOr() to return false when every instance of your condition must pass independently.

For example, two biome conditions mean “biome A OR biome B”; a biome condition plus a height condition means “biome matches AND height matches.”

Failure and side rules

test is called during recipe matching and while working conditions are checked. Keep it deterministic and cheap. Do not load chunks, spawn entities, edit NBT, or consume a capability. Use a trait handler or machine event for mutation.