FastCrystal

Evidence

Ran on Kiln's test stand (2026-11-04): FastCrystal did not start: java.lang.NoClassDefFoundError: net/minecraft/network/protocol/Packet.

What it needs from Kiln

• Mixin
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents.Disconnect
• 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.networking.v1.PayloadTypeRegistry
• net.minecraft.client.multiplayer.PlayerInfo
• net.minecraft.client.multiplayer.chat.ChatListener
• net.minecraft.core.RegistryAccess
• net.minecraft.core.particles.ParticleTypes
• 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.ClientboundCommandSuggestionsPacket
• net.minecraft.network.protocol.game.ClientboundPlayerInfoUpdatePacket
• net.minecraft.network.protocol.game.ClientboundPlayerInfoUpdatePacket.Action
• net.minecraft.network.protocol.game.ClientboundPlayerInfoUpdatePacket.Entry
• net.minecraft.network.protocol.game.ServerboundAttackPacket
• net.minecraft.network.protocol.game.ServerboundCommandSuggestionPacket
• net.minecraft.network.protocol.game.ServerboundSetCarriedItemPacket
• net.minecraft.network.protocol.game.ServerboundUseItemOnPacket
• net.minecraft.world.effect.MobEffectInstance
• net.minecraft.world.effect.MobEffects
• net.minecraft.world.entity.Entity.RemovalReason
• net.minecraft.world.entity.EntityTypes
• net.minecraft.world.entity.boss.enderdragon.EndCrystal
• net.minecraft.world.item.enchantment.Enchantments
• net.minecraft.world.item.enchantment.ItemEnchantments
• net.minecraft.world.level.ClipContext
• net.minecraft.world.level.ClipContext.Block
• net.minecraft.world.level.ClipContext.Fluid
• net.minecraft.world.phys.AABB
• net.minecraft.world.phys.HitResult.Type
• net.minecraft.network.protocol.Packet
• Minecraft.execute()
• Minecraft.gameMode
• Minecraft.getCameraEntity()
• Gui.chatListener()
• ClientLevel.addEntity()
• and 37 more

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

In the author's words

Fastest possible crystal optimizer

Scan

Scanned on 4 November 2026 against Kiln 0.2.0, file fastcrystal-2.1.5+26.3.jar. The scan reads the mod's classes; it does not run them.