# Geargrafx MCP Server

Embedded MCP server inside the Geargrafx PC Engine and TurboGrafx-16 emulator. It gives AI coding assistants execution control, memory inspection, and debugger access.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed · ★ 248
- Author: drhelius
- License: GPL-3.0 · policy=link-only · description only; the file stays with the author
- Source: https://github.com/drhelius/Geargrafx
- Updated: 2026-10-24
- HTML: https://affpapa.org/en/nevibecode/mcp/geargrafx-mcp-server

## What it does

Geargrafx is an open-source PC Engine, TurboGrafx-16, and SuperGrafx emulator built with C++. Instead of relying on external bridge scripts, it embeds a native MCP server directly into the core application. This setup lets coding assistants interact with the running emulation process during homebrew software testing or reverse engineering.

The server exposes actions to inspect system RAM, examine video registers, step through CPU execution, and trigger frame rewinds. Through these tools, models can monitor background layers, check sprite buffers, and verify hardware states across both HuCard and CD-ROM games.

On Linux systems, the binary may require `libsdl3` to run properly. Windows builds depend on the Visual C++ Redistributable and the OpenGL Compatibility Pack, while macOS users can fetch the desktop build via `brew install --cask drhelius/geardome/geargrafx`.

## Install

### Claude Code (native platform)

**Install**
- The MCP registry has no launch command for it: see the repository README

## When to use it
- inspect system RAM and hardware registers inside a running PC Engine emulator
- control execution flow and step through instructions via an AI agent
- debug homebrew TurboGrafx-16 software by checking video display controller state
- rewind emulation frames to reproduce subtle logic bugs

## Example prompts
- Read the VDC registers and check which background layers are active
- Pause emulation and dump the RAM contents starting at memory address $2200
- Rewind the game by ten frames and report the CPU status flags

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