What Do You Mean? - Fabric 1.21 Mod

A live debugging assistant that lives inside your Minecraft client.

Press F10 in-game to open The Doctor, a conversational debugging tool that can explain current behavior, inspect what's under your crosshair, diagnose lag spikes, read mod and vanilla source without leaving the game, arm runtime conditions that fire later, and apply live bytecode patches with rollback. Everything happens inside the running client. Zero restarts.

What you can do with it

  - Ask questions about the game you're playing. The Doctor pulls live diagnostic context, your session state, and loaded mod info, then answers in natural language.

  - Find what's weird. Look at anything (a block, an entity, a container) and the Doctor tells you what it is and what it knows about itself (DataComponents and NBT).

  - Arm conditions with WHEN. "When [any valid java condition], remind me." Go back to playing. The Doctor pings you when it fires.

  - Patch the game while it's running. Try a behavior change without a recompile. If the patch fails, it rolls back cleanly.

 - Read source from inside the game. Any loaded class, any member, any jar on disk, decompiled on the fly if no source ships.

 - Get warned about wEiRdNeSs before you ask. The Watchdog samples runtime health in the background and surfaces anomalies as toasts and logs to enhance The Doctor's context. 

- Toy with an experimental semantic memory system (Engram) that learns from your interactions over time.

Install

  1. Minecraft Java Edition 1.21

  2. Fabric Loader for 1.21

  3. Drop the jar into your mods/ folder

  4. Launch once to generate config/what-do-you-mean.json

  5. Configure a model provider (OpenRouter API key, or an installed CLI like Claude Code, Codex, or Gemini CLI)

  6. Press F10 in-game

Notes

- Client-side mod. Runs on your local game; no server setup required.

- Requires an external model provider; whether through API (openrouter) or installed CLI tool like Claude Code. The Doctor's reasoning goes through the provider you configure.

- Patching is experimental. Rollback is always available, but live runtime modification is inherently fragile across modpack combinations. 

AI disclosure. I used AI coding tools (Claude Code, OpenAI Codex) as a pair-programmer to help with repetitive work like regex parsing, some UI boilerplate, and scaffolding. The architecture, the patching system, the agent loop, the context pipeline, and the documentation were written by me. I like my voice and ideas. There is no AI-generated art/sounds/media in this tool.  It does require interfacing with LLM technologies at its core tho. 

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Built as a capstone project at Humber Polytechnic, 2026. Source and full documentation: woflo.dev/projects