MCP Server

Model context protocol server for openMSX automation and control

Remote serverstreamable-httpTypeScript

What is the MCP MCP server?

Connect MCP to Claude, Cursor or any other MCP client and it stops being a tab you switch to. Model context protocol server for openMSX automation and control. The mcp mcp server is what makes that connection.

What the server does

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

Installation

Because this one is hosted, setup is mostly authentication — you point your client at the endpoint and approve access. Nothing runs on your machine, so there is no runtime to keep patched.

Available tools

The toolset is worth reading before you wire it up, because it tells you what the integration is really for:

  • 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
  • basic_programming — BASIC tools: isBasicAvailable, newProgram, runProgram, setProgram, getFullProgram, getFullProgramAdvanced, listProgramLines, deleteProgramLines
  • 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
  • debug_memory — RAM memory operations: selectedSlots, getBlock, readByte, readWord, writeByte, writeWord, searchBytes
  • debug_vram — VRAM operations: getBlock, readByte, writeByte, searchBytes
  • debug_breakpoints — Breakpoint management: create, remove, list
  • emu_keyboard — Send text or key combinations to emulator: sendText, sendKeyCombo

Credentials and setup notes

Configuration is passed through the environment: OPENMSX_SHARE_DIR, OPENMSX_ENABLE_RAW_TCL, OPENMSX_EXECUTABLE, OPENMSX_SCREENSHOT_DIR, OPENMSX_SCREENDUMP_DIR, OPENMSX_REPLAYS_DIR, MCP_HTTP_PORT, MCP_ALLOWED_ORIGINS. Treat anything key-shaped as a real credential — scope it to the minimum the server needs, and rotate it if it ever lands in a shared config.

  • Node.js >= 18.0.0 - TypeScript - openMSX emulator installed

Worth knowing first

  • Your data travels to the provider's service, so the usual questions apply about what you send and what they retain.
  • With 14 tools registered it takes up a noticeable share of the context window; turn it off in projects that never touch MCP.
  • Keep per-call confirmation enabled while you learn its behaviour; it is the cheapest safeguard you have.

Where it fits

Among the knowledge and memory options, the useful question is rarely "what can it do" but "what does it cost you to run" — permissions, credentials, and how much of your context its toolset consumes. MCP's toolset — emu_control, emu_replay, emu_info and 11 more — is a fair guide to whether it matches your workflow. It is maintained by nataliapc; worth a glance at recent repository activity before you build anything load-bearing on it.

SyncDev reviews every entry in this directory against the project's own documentation before publishing, and revisits them as servers change.

Available tools

ToolWhat it does
emu_controlControls an openMSX emulator: _launch, close, powerOn, powerOff, reset, getEmulatorSpeed, setEmulatorSpeed, machineList, extensionList, wait_.
emu_replayControls emulation timeline: _start, stop, status, goBack, absoluteGoto, advanceFrame, reverseFrame, truncate, saveReplay, loadReplay_.
emu_infoObtain informacion about the current emulated machine: _getStatus, getSlotsMap, getIOPortsMap_.
emu_mediaManage ROM, disk, and tape media: _tapeInsert, tapeRewind, tapeEject, romInsert, romEject, diskInsert, diskInsertFolder, diskEject_.
emu_vdpManage VDP (Video Display Processor): _getPalette, getRegisters, getRegisterValue, setRegisterValue, screenGetMode, screenGetFullText_.
basic_programmingBASIC tools: _isBasicAvailable, newProgram, runProgram, setProgram, getFullProgram, getFullProgramAdvanced, listProgramLines, deleteProgramLines_.
debug_runControl execution: _break, isBreaked, continue, stepIn, stepOut, stepOver, stepBack, runTo_.
debug_cpuRead/write CPU registers, CPU info, Stack pile, and Disassemble code: _getCpuRegisters, getRegister, setRegister, getStackPile, disassemble, getActiveCpu_.
debug_memoryRAM memory operations: _selectedSlots, getBlock, readByte, readWord, writeByte, writeWord, searchBytes_.
debug_vramVRAM operations: _getBlock, readByte, writeByte, searchBytes_.
debug_breakpointsBreakpoint management: _create, remove, list_.
emu_keyboardSend text or key combinations to emulator: _sendText, sendKeyCombo_.
emu_savestatesSave and restore machine states: _load, save, list_.
screen_shotCapture emulator screen: _as_image, to_file_.

How to install the MCP MCP server

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

Configuration as documented by the project. Restart the client after saving.

Configuration

  • Node.js >= 18.0.0 - TypeScript - openMSX emulator installed
VariableDescriptionRequired
OPENMSX_SHARE_DIRFilesystem location the server is allowed to use.Optional
OPENMSX_ENABLE_RAW_TCLConfiguration value read at startup.Optional
OPENMSX_EXECUTABLEConfiguration value read at startup.Optional
OPENMSX_SCREENSHOT_DIRFilesystem location the server is allowed to use.Optional
OPENMSX_SCREENDUMP_DIRFilesystem location the server is allowed to use.Optional
OPENMSX_REPLAYS_DIRFilesystem location the server is allowed to use.Optional
MCP_HTTP_PORTConfiguration value read at startup.Optional
MCP_ALLOWED_ORIGINSConfiguration value read at startup.Optional

Example prompts to try

  • Use MCP to emu control.
  • Use MCP to emu replay.
  • Use MCP to emu info.

Frequently asked questions

It connects MCP to MCP-compatible AI assistants such as Claude and Cursor, exposing 14 tools (emu_control, emu_replay, emu_info, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with MCP directly.