Flyspeed

Evidence

Ran on Kiln's test stand (2026-11-04): Flyspeed did not start: java.lang.NoClassDefFoundError: net/minecraft/network/protocol/common/custom/CustomPacketPayload; FlyspeedClient did not start: java.lang.NoClassDefFoundError: net/minecraft/network/chat/FormattedText.

What it needs from Kiln

• com.mojang.blaze3d.platform.InputConstants.Key
• com.mojang.blaze3d.platform.Window
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents.Disconnect
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents.Join
• 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.PacketSender
• net.fabricmc.fabric.api.networking.v1.PayloadTypeRegistry
• net.fabricmc.fabric.api.networking.v1.ServerPlayConnectionEvents
• net.fabricmc.fabric.api.networking.v1.ServerPlayConnectionEvents.Join
• net.fabricmc.fabric.api.networking.v1.ServerPlayNetworking
• net.minecraft.client.Options
• net.minecraft.client.gui.components.AbstractSliderButton
• net.minecraft.client.gui.components.Button
• net.minecraft.client.gui.components.Button.Builder
• net.minecraft.client.gui.components.Button.OnPress
• 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.world.entity.player.Abilities
• org.lwjgl.sdl.SDLMouse
• net.minecraft.network.chat.FormattedText
• InputConstants.UNKNOWN
• InputConstants.isKeyDown()
• KeyMappingHelper.getBoundKeyOf()
• KeyMapping.isUnbound()
• Minecraft.getSingleplayerServer()
• Minecraft.getWindow()
• Minecraft.isWindowActive()
• Minecraft.options
• Font.width()
• GuiGraphicsExtractor.centeredText()
• GuiGraphicsExtractor.fillGradient()
• GuiGraphicsExtractor.outline()
• GuiGraphicsExtractor.textWithWordWrap()
• Screen.extractRenderState()
• and 3 more

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

In the author's words

Boost creative & survival flight speed up to 20x with Hold/Toggle control.

Scan

Scanned on 4 November 2026 against Kiln 0.2.0, file flyspeed-26.3.1.jar. The scan reads the mod's classes; it does not run them.