Gearboy MCP Server

What Gearboy MCP Server does

Gearboy MCP Server connects MCP-compatible AI assistants to Gearboy, an emulator for Nintendo Game Boy, Game Boy Color, and Super Game Boy software. Its purpose is AI-assisted debugging and development rather than general game-library management. Through the embedded MCP interface, an assistant can interact with emulator state while a ROM is running.

The underlying emulator includes a full debugger with a just-in-time disassembler, CPU and memory-access breakpoints, code navigation, symbol support, automatic labels, a memory editor, trace logging, an I/O inspector, and a VRAM viewer. The MCP feature exposes selected emulator and debugging operations to AI tools, including execution control, memory inspection, hardware-status inspection, and rewind.

How it works

Gearboy is a native C++ application with the MCP server built into the emulator. The emulator loads supported Game Boy-family ROMs, and an MCP client can then invoke the available debugging and control functions against that running session. This arrangement is suited to examining program behavior, checking memory and hardware state, and changing execution position during development.

The emulator supports ROM files in common Game Boy formats and ZIP archives. It can also load optional symbol files, including formats associated with RGBDS, GBDK-2020, WLA-DX, no$gmb, SDCC/NoICE, EQU, and generic symbol data. These debugging facilities can provide more useful context when working on homebrew software or analyzing an existing ROM.

Setup and configuration

Gearboy is distributed for Windows, macOS, Linux, and BSD. The project lists an MCPB package for all platforms alongside its desktop downloads. Install the Gearboy build appropriate for the host system, then connect the MCP-capable client to the embedded MCP server using the package's MCP setup instructions.

Linux installations may require SDL3. Windows systems may require the Visual C++ Redistributable and the OpenGL Compatibility Pack. Gearboy also supports portable mode, which can keep configuration and save data alongside the application; start it with --portable or create an empty portable.ini beside the application binary.

Tools and capabilities

The MCP interface is intended for AI-assisted emulator debugging and exposes capabilities for:

• Controlling execution.
• Inspecting emulated memory.
• Reading hardware status.
• Rewinding emulator state.
• Working with additional debugging state exposed by Gearboy.

Gearboy itself adds save states with preview and rewind, battery-backed RAM saves, boot ROM support, cheat support, and a VGM recorder. It also provides local two-instance Game Boy link-cable support on desktop platforms and the libretro core.

Limitations and notes

The MCP functions operate within Gearboy's emulation model and supported platforms. The emulator targets Game Boy, Game Boy Color, and Super Game Boy software; it is not a general-purpose debugging interface for arbitrary applications. Link-cable sessions require two desktop emulator instances configured to share a session, with separate application copies or portable data directories recommended to avoid conflicts.

Supported AI clients named by the project include GitHub Copilot, Claude, and Codex. The emulator's broader platform support through libretro is separate from its standalone desktop builds and should not be assumed to provide identical MCP behavior.