Hotbar Helper

Evidence

Ran on Kiln's test stand (2026-11-04): HotbarHelper did not start: java.lang.NoClassDefFoundError: net/minecraft/network/protocol/common/custom/CustomPacketPayload; HotbarHelperClient did not start: java.lang.NoClassDefFoundError: net/minecraft/core/RegistryAccess.

What it needs from Kiln

• Mixin
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking.Context
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking.PlayPayloadHandler
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerLevelEvents
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerLevelEvents.Load
• net.fabricmc.fabric.api.event.player.AttackBlockCallback
• net.fabricmc.fabric.api.event.player.UseBlockCallback
• net.fabricmc.fabric.api.event.player.UseEntityCallback
• net.fabricmc.fabric.api.event.player.UseItemCallback
• net.fabricmc.fabric.api.networking.v1.PacketSender
• net.fabricmc.fabric.api.networking.v1.PayloadTypeRegistry
• net.fabricmc.fabric.api.networking.v1.ServerPlayConnectionEvents
• net.fabricmc.fabric.api.networking.v1.ServerPlayConnectionEvents.Join
• net.minecraft.client.Options
• net.minecraft.core.HolderLookup.RegistryLookup
• net.minecraft.core.HolderSet
• net.minecraft.core.HolderSet.Named
• net.minecraft.core.RegistryAccess
• net.minecraft.core.RegistryAccess.Frozen
• net.minecraft.network.HashedStack
• net.minecraft.network.codec.ByteBufCodecs
• net.minecraft.network.codec.StreamCodec
• net.minecraft.network.protocol.common.custom.CustomPacketPayload
• net.minecraft.network.protocol.common.custom.CustomPacketPayload.Type
• net.minecraft.network.protocol.common.custom.CustomPacketPayload.TypeAndCodec
• net.minecraft.network.protocol.game.ServerboundContainerClickPacket
• net.minecraft.network.protocol.game.ServerboundSetCarriedItemPacket
• net.minecraft.server.MinecraftServer
• net.minecraft.tags.TagKey
• net.minecraft.world.entity.player.Inventory
• net.minecraft.world.inventory.ContainerInput
• net.minecraft.world.inventory.InventoryMenu
• net.minecraft.world.item.ArmorStandItem
• net.minecraft.world.item.BoatItem
• net.minecraft.world.item.EndCrystalItem
• net.minecraft.world.item.HangingEntityItem
• net.minecraft.world.item.MinecartItem
• net.minecraft.world.item.MobBucketItem
• net.minecraft.world.item.SpawnEggItem
• net.minecraft.world.item.enchantment.EnchantmentHelper
• and 37 more

On the roadmap: Minecraft's libraries and client API (0.2), Code next to data (0.3), Machines (0.4), Mixin (0.5)

In the author's words

Switches tools while mining and refills your hotbar

Scan

Scanned on 4 November 2026 against Kiln 0.2.0, file hotbar-helper-(26.3)-1.0.1.jar. The scan reads the mod's classes; it does not run them.