MCP-openMSX

"Orchestrating a binary opera where AI conducts, MCP interprets, and openMSX acts as the 8-bit diva."

A Model Context Protocol (MCP) server for automating openMSX emulator instances.

This server provides comprehensive tools for MSX software development, testing, and automation through standardized MCP protocols.

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Project overview
Architecture
Available MCP Tools
Available MCP Resources
⚡ Quick Start
Advanced manual usage
Development
License
Support
Contributing
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Project Overview

This project creates a bridge between modern AI-assisted development (e.g. GitHub Copilot, Claude Desktop) and retro computing (MSX systems) by providing:

Emulator Control: Launch, configure, manage openMSX instances, and replay timelines.
Media Management: Handle ROM cartridges, floppy disks, and cassette tapes.
BASIC Programming Support: Tools to facilitate BASIC language programming and development.
Debugging Tools: Full CPU debugging with breakpoints, memory inspection, and step execution.
Video Control: VDP register manipulation and screen capture.
Memory Operations: Read/write RAM, VRAM, and I/O port access.
Automation: Keyboard input simulation and savestate management.
Vector DB Integration: Query an embedded vector database with MSX resources for development support.
Hybrid Mode: This MCP server supports hybrid access mode (STDIO and HTTP transports).

Architecture

flowchart TB
  %%{init: {'flowchart': {'curve':'monotoneX' }}}%%

  subgraph yourComputerGroup[" "]
    HOST["Your AI dev companion<br>(MCP Client support)"]
    EMU["openMSX emulator<br>(local instance)"]

    subgraph mcpGroup["**mcp-openmsx**"]
      MCP["MCP Server<br>stdio / http"]
      TOOLS["MCP Tools"]
      VECTORDB[("Embeddings RAG<br>(Vector Database)")]
      RESOURCES["MCP Resources"]
      LOCALDATA["Local data<br>(inner documentation)"]
    end
    EXTDATA["External data<br>(webpages)"]

    HOST <--"_MCP<br>&nbsp;protocol&nbsp;_"--> MCP
    MCP <--> TOOLS & RESOURCES
    TOOLS <--"_&nbsp;Query&nbsp;_"--> VECTORDB
    TOOLS <--"_&nbsp;Console commands&nbsp;_"---> EMU
    RESOURCES <--_&nbsp;http&nbsp;_---> EXTDATA
    RESOURCES <--> LOCALDATA
  end

  HOST@{ shape: rounded }
  MCP@{ shape: rounded }
  EMU@{ shape: rounded }
  LOCALDATA@{ shape: docs }
  EXTDATA@{ shape: docs }
  style yourComputerGroup color:#fff,fill:#4444,text-align:left
  style mcpGroup color:#fff,fill:#4444
  style HOST color:#000000,fill:#BBDEFB,stroke-width:4px,stroke-dasharray:0
  style MCP color:#000000,fill:#FFF9C4
  style EMU color:#FFFFFF,fill:#0000FF,stroke-width:4px,stroke-dasharray:0

The MCP server translates high-level natural language commands from your Copilot AI into TCL commands to control openMSX, enabling automated MSX software testing and debugging.

Available MCP Tools

Emulator Control Tools

emu_control: Controls an openMSX emulator: launch, close, powerOn, powerOff, reset, getEmulatorSpeed, setEmulatorSpeed, machineList, extensionList, wait.
emu_replay: Controls emulation timeline: start, stop, status, goBack, absoluteGoto, advanceFrame, reverseFrame, truncate, saveReplay, loadReplay.
emu_info: Obtain informacion about the current emulated machine: getStatus, getSlotsMap, getIOPortsMap.
emu_media: Manage ROM, disk, and tape media: tapeInsert, tapeRewind, tapeEject, romInsert, romEject, diskInsert, diskInsertFolder, diskEject.
emu_vdp: Manage VDP (Video Display Processor): getPalette, getRegisters, getRegisterValue, setRegisterValue, screenGetMode, screenGetFullText.

Programming Tools

basic_programming: BASIC tools: isBasicAvailable, newProgram, runProgram, setProgram, getFullProgram, getFullProgramAdvanced, listProgramLines, deleteProgramLines.

Debugging Tools

debug_run: Control execution: break, isBreaked, continue, stepIn, stepOut, stepOver, stepBack, runTo.
debug_cpu: Read/write CPU registers, CPU info, Stack pile, and Disassemble code: getCpuRegisters, getRegister, setRegister, getStackPile, disassemble, getActiveCpu.
debug_memory: RAM memory operations: selectedSlots, getBlock, readByte, readWord, writeByte, writeWord, advanced_basic_listing.
debug_vram: VRAM operations: getBlock, readByte, writeByte.
debug_breakpoints: Breakpoint management: create, remove, list.

Automation Tools

emu_keyboard: Send text input to emulator: sendText.
emu_savestates: Save and restore machine states: load, save, list.
screen_shot: Capture emulator screen: as_image, to_file.
screen_dump: Export screen data as BASIC BSAVE instruction.
msxdocs_resource_get: Retrieve MCP resources for MCP clients that don't support MCP resources.

Documentation Tools

vector_db_query: Query the Vector DB resources to obtain information about MSX systems, cartridges, and other development resources.
msxdocs_resource_get: Retrieve MCP resources for MCP clients that don't support MCP resources.

Available MCP Resources

What are MCP Resources?

MCP resources are structured data sets, documentation, and helper files that extend the capabilities of the MCP server. They provide essential information such as machine definitions, extension lists, media templates, and programming examples, enabling more powerful automation, testing, and development workflows for MSX software within the MCP-openMSX environment.

Available Resources

There are more than 60 resources available, some included directly in the MCP and others accessible via download when queried. They are organized into the following categories:

Processors (Z80, R800)
Bios (Bios ROM, DOS ROM, SUBROM, ...)
System
Audio
Video
Programming (ASM, BASIC, ...)
MSX-DOS
MSX-UNAPI
MSX BASIC

And books and manuals:

MSX2 Technical Handbook
The MSX Red Book
SDCC Compiler

Thanks to the authors of these resources, who have made them available under various licenses. This MCP server includes some of these resources to enhance the development experience.

[!IMPORTANT]
The rights to these resources belong to their respective authors and are distributed under the licenses they have defined.

Quick Start

You can use this MCP server in this basic way with the precompiled NPM package.

Quick installation with VSCode

Steps to install the MCP server in VSCode:

Install Github Copilot extension
Install nodejs (npx command must be available in your PATH).
Install de MCP Server:
- Use the Install MCP Server button above to install the MCP server in your VSCode settings.
- Or add to your workspace folder a file named .vscode/mcp.json with the json configuration below.

STDIO mode (recommended)

{
  "servers": {
    "mcp-openmsx": {
      "command": "npx",
      "args": ["@nataliapc/mcp-openmsx"],
      "env": {
        "OPENMSX_SHARE_DIR": "C:\\the\\location\\of\\your\\openmsx\\share\\folder"
      }
    }
  }
}

[!NOTE]
Environment variables are optional. Customize them as you need.

Streamed HTTP mode (more advanced)

{
  "servers": {
    "mcp-openmsx": {
      "type": "http",
      "url": "http://localhost:3000/mcp",
      "headers": { }
    }
  }
}

[!NOTE]
The MCP HTTP Server must be running standalone in the same computer or in another (make run_http).

Basic Installation with Claude Desktop

Follow these instrutions to access Claude's claude_desktop_config.json file.

Edit it to include the following JSON entry:

{
  "mcpServers": {
    "mcp-openmsx": {
      "command": "npx",
      "args": ["@nataliapc/mcp-openmsx"],
      "env": {
        "OPENMSX_SHARE_DIR": "C:\\the\\location\\of\\your\\openmsx\\share\\folder"
      }
    }
  }
}

[!NOTE]
Environment variables are optional. Customize them as you need.

Environment Variables

Variable	Description	Default Value	Example
`OPENMSX_EXECUTABLE`	Path or command to the openMSX executable	`openmsx`	`/usr/local/bin/openmsx`
`OPENMSX_SHARE_DIR`	Directory containing openMSX data files (machines, extensions, etc.)	System dependent	`/home/myuser/.openmsx/share`
`OPENMSX_SCREENSHOT_DIR`	Directory where screenshots will be saved	Default for openmsx	`/myproject/screenshots`
`OPENMSX_SCREENDUMP_DIR`	Directory where screen dumps will be saved	Default for openmsx	`/myproject/screendumps`
`OPENMSX_REPLAYS_DIR`	Directory where replay files will be saved	Default for openmsx	`/myproject/replays`
`MCP_TRANSPORT`	Transport mode (`stdio` or `http`)	`stdio`	`http`
`MCP_HTTP_PORT`	Port number for HTTP transport mode	`3000`	`8080`

Advanced Manual Usage

[!IMPORTANT]
This is not needed for using the MCP server, but if you want to install it manually, follow these steps.

Currently, the MCP server requires Linux to be compiled. It has not been tested on Windows or macOS, although it will likely work on the latter as well.

Manual installation

npm install -g @nataliapc/mcp-openmsx

Manual set of Environment Variables

Set optional environment variables to customize the server:

export OPENMSX_EXECUTABLE="openmsx"
export OPENMSX_SHARE_DIR="/usr/share/openmsx"
export OPENMSX_SCREENSHOT_DIR="/my_project/screenshots"
export OPENMSX_SCREENDUMP_DIR="/my_project/screendumps"
export OPENMSX_REPLAYS_DIR="/my_project/replays"
export MCP_HTTP_PORT=3000

As MCP Server (stdio)

mcp-openmsx

As HTTP Server

MCP_TRANSPORT=http mcp-openmsx
# or
mcp-openmsx http

Development

[!IMPORTANT]
This is not needed for using the MCP server, but if you want to contribute or modify the code, follow these steps.

Prerequisites to build

Node.js >= 18.0.0
TypeScript
openMSX emulator installed

Building

git clone https://github.com/nataliapc/mcp-openmsx.git
cd mcp-openmsx/mcp-server
npm install
npm run build

Running in Development

npm run dev

License

GPL2 License - see LICENSE file for details.

Support

If you need help, or have questions or suggestions, please open an issue on the GitHub Issues page or check the project discussions.

OpenMSX