Fabric API MCP Server

Evidence

Ran on Kiln's test stand (2026-11-04): McpServerMod did not start: java.lang.NoClassDefFoundError: net/fabricmc/fabric/api/event/lifecycle/v1/ServerLifecycleEvents; McpClientMod did not start: java.lang.NoClassDefFoundError: net/fabricmc/fabric/api/client/event/lifecycle/v1/ClientLifecycleEvents.

What it needs from Kiln

• an access widener
• com.mojang.authlib.GameProfile
• com.mojang.blaze3d.pipeline.RenderTarget
• com.mojang.blaze3d.platform.NativeImage
• net.fabricmc.fabric.api.attachment.v1.AttachmentTarget
• net.fabricmc.fabric.api.attachment.v1.AttachmentType
• net.fabricmc.fabric.api.block.v1.FluidFlowEvents
• net.fabricmc.fabric.api.block.v1.FluidFlowEvents.Allow
• net.fabricmc.fabric.api.client.event.lifecycle.v1.ClientLifecycleEvents
• net.fabricmc.fabric.api.client.event.lifecycle.v1.ClientLifecycleEvents.ClientStarted
• net.fabricmc.fabric.api.client.event.lifecycle.v1.ClientLifecycleEvents.ClientStopping
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents.ServerStarted
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents.ServerStarting
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents.ServerStopped
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerLifecycleEvents.ServerStopping
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerTickEvents
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerTickEvents.EndTick
• net.fabricmc.fabric.api.event.player.AttackBlockCallback
• net.fabricmc.fabric.api.event.player.UseBlockCallback
• net.fabricmc.fabric.api.lookup.v1.block.BlockApiLookup
• net.fabricmc.fabric.api.message.v1.ServerMessageEvents
• net.fabricmc.fabric.api.message.v1.ServerMessageEvents.ChatMessage
• net.fabricmc.fabric.api.networking.v1.ServerPlayConnectionEvents
• net.fabricmc.fabric.api.networking.v1.ServerPlayConnectionEvents.Disconnect
• net.fabricmc.fabric.api.networking.v1.ServerPlayConnectionEvents.Join
• net.fabricmc.fabric.api.registry.FlammableBlockRegistry
• net.fabricmc.fabric.api.registry.FlammableBlockRegistry.Entry
• net.fabricmc.fabric.api.resource.conditions.v1.ResourceCondition
• net.fabricmc.fabric.api.resource.conditions.v1.ResourceConditionType
• net.fabricmc.fabric.api.transfer.v1.fluid.FluidStorage
• net.fabricmc.fabric.api.transfer.v1.fluid.FluidVariant
• net.fabricmc.fabric.api.transfer.v1.storage.Storage
• net.fabricmc.fabric.api.transfer.v1.storage.StorageView
• net.fabricmc.fabric.api.transfer.v1.transaction.Transaction
• net.fabricmc.fabric.impl.attachment.AttachmentRegistryImpl
• net.fabricmc.loader.api.ModContainer
• net.fabricmc.loader.api.SemanticVersion
• net.fabricmc.loader.api.Version
• net.fabricmc.loader.api.VersionParsingException
• net.fabricmc.loader.api.metadata.ModMetadata
• and 80 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

A Model Context Protocol (MCP) server that runs inside Minecraft Java Edition as a Fabric mod. It exposes the server-side Minecraft API and the Fabric API as MCP tools so Claude, Cursor, etc. can read and manipulate a live world programmatically.

Scan

Scanned on 4 November 2026 against Kiln 0.2.0, file minecraft-fabric-mcp-1.2.0+26.3.jar. The scan reads the mod's classes; it does not run them.