👾🦀 MiSTerClaw — MCP Remote Control for MiSTer-FPGA

MiSTerClaw is the first MCP server for MiSTer-FPGA. Control your MiSTer from any AI agent.

What is this?

MiSTerClaw lets AI agents — Claude, ChatGPT, OpenClaw, Hermes, Cursor, and others — control a MiSTer-FPGA over the network. Launch games, search your ROM library, take screenshots, read and modify core settings and DIP switches, navigate the OSD menu using conf_str-based position calculation (experimental, not yet reliable for all cores), query detailed system information, manage the system, and even set up Tailscale VPN for secure remote access from anywhere. Floppy-disk cores (PC8801, MSX, etc.) support PostLaunch auto-reset for seamless game loading. It uses the Model Context Protocol (MCP) standard, so any MCP-compatible client works out of the box. For agents without MCP support, a CLI client is also included.

MCP Setup

Add MiSTerClaw to your MCP client config:

Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "misterclaw": {
      "command": "/path/to/misterclaw-mcp",
      "args": ["--host", "mister-fpga"]
    }
  }
}

Cursor (.cursor/mcp.json):

{
  "mcpServers": {
    "misterclaw": {
      "command": "/path/to/misterclaw-mcp",
      "args": ["--host", "mister-fpga"]
    }
  }
}

MCP Tools

Example Conversations

Once configured, just talk to your agent:

You: "What games do I have for SNES?"
Agent: You have 13,435 SNES ROMs! Here are some highlights...

You: "Launch Street Fighter 2"
Agent: 🎮 Launched Street Fighter II Turbo on SNES!

You: "Take a screenshot and show me"
Agent: [screenshot of the game running]

You: "What systems do I have?"
Agent: Your MiSTer has 70+ systems! Top ones:
  - SNES: 13,435 ROMs
  - C64: 46,736 ROMs
  - Amiga: 55,793 ROMs
  ...

You: "Set up Tailscale so I can reach the MiSTer from anywhere"
Agent: Installing Tailscale... Done!
       Please authenticate: https://login.tailscale.com/a/xxx
       After that your MiSTer is reachable from anywhere.

You: "What settings does R-Type have?"
Agent: R-Type (M72 core) has these settings:
       Core Options:
         - No Death Mode: Off
         - Service Mode: Off
       DIP Switches:
         - Difficulty: Medium
         - Coin A: 1 Coin / 1 Credit
         - Lives: 3
         - Demo Sounds: On
         - Continue: Yes

You: "Enable No Death Mode"
Agent: ⚙️ Set "No Death Mode" to On in R-Type.
       The core reloads automatically — change is live!

You: "Navigate to the Reset option in the OSD"
Agent: Navigated to Reset in the SNES core OSD.

You: "What do I need to know about the PC8801 system?"
Agent: PC8801 uses the PC8801 core with .d88 floppy disk images.
       Notes: After loading a disk, press F12 → Reset to boot.
       OSD Menu: FDD0, FDD1, Reset, CPU Speed, ...

CLI Client

For agents that have shell access (like OpenClaw, Codex, or Claude Code), the CLI client can be more efficient than MCP — no tool schemas in context, just call it when needed. It's also useful for shell scripts and automation.

# Check what's playing
misterclaw-send -H mister-fpga status

# Search for games
misterclaw-send -H mister-fpga search "zelda" --limit 5
misterclaw-send -H mister-fpga search "sonic" --system MegaDrive

# Launch a game
misterclaw-send -H mister-fpga launch "super mario world" --system SNES

# List all systems with ROM counts
misterclaw-send -H mister-fpga systems

# Take a screenshot
misterclaw-send -H mister-fpga screenshot -o game.png

# System info (CPU, memory, storage, uptime)
misterclaw-send -H mister-fpga info

# Run shell commands — configure MiSTer.ini, run updates, manage files
misterclaw-send -H mister-fpga shell "cat /media/fat/MiSTer.ini"
misterclaw-send -H mister-fpga shell "/media/fat/Scripts/update_all.sh"

# Send keyboard input (OSD navigation)
misterclaw-send -H mister-fpga input key osd
misterclaw-send -H mister-fpga input combo leftalt f12

# Query OSD menu structure
misterclaw-send -H mister-fpga osd-info
misterclaw-send -H mister-fpga osd-info --core SNES

# Navigate to a specific OSD menu item
misterclaw-send -H mister-fpga osd-navigate Reset
misterclaw-send -H mister-fpga osd-navigate "Aspect ratio"

# Get detailed system info (config, notes, OSD menu)
misterclaw-send -H mister-fpga system-info PC8801
misterclaw-send -H mister-fpga system-info SNES

# Read core settings (options + DIP switches)
misterclaw-send -H mister-fpga cfg-read

# Modify settings
misterclaw-send -H mister-fpga cfg-write --option "Free Play" --value On

# Reload core to apply changes
misterclaw-send -H mister-fpga reload

# Rescan ROM library (after adding new games)
misterclaw-send -H mister-fpga rescan
misterclaw-send -H mister-fpga rescan --location usb0

# JSON output for scripting
misterclaw-send -H mister-fpga status --json
misterclaw-send -H mister-fpga systems --json

All commands support --json for machine-readable output.

Installation

Three binaries:

Quick install on MiSTer

scp misterclaw root@<mister-ip>:/media/fat/Scripts/
ssh root@<mister-ip> "/media/fat/Scripts/misterclaw --install"

Or self-install: copy the binary to MiSTer, then run misterclaw --install. This copies to /media/fat/Scripts/, configures autostart on boot, and is idempotent.

To uninstall: /media/fat/Scripts/misterclaw --uninstall

Security

⚠️ Do not expose port 9900 to the internet. The ClawExec protocol has no authentication or encryption.

• Tailscale VPN (recommended) — encrypted, authenticated, works from anywhere
• Local network only — keep port 9900 accessible within your LAN
• Never forward port 9900 through your router or firewall

Architecture

Agent ←MCP→ misterclaw-mcp ←TCP→ MiSTer:9900 (misterclaw server)
Agent ←CLI→ misterclaw-send ←TCP→ MiSTer:9900 (misterclaw server)

The MCP server and CLI client communicate with the MiSTer over the ClawExec protocol (newline-delimited JSON over TCP, port 9900).

Dynamic System Detection

MiSTerClaw auto-detects all systems by scanning ROM folders, installed cores, and MGL files. No configuration needed — a well-stocked MiSTer typically has 70+ systems. Discovery results (including full ROM file listings) are cached to disk. First startup scans and builds the cache; subsequent starts load instantly. Use the rescan command after adding new games or drives.

Building from Source

# MiSTer server (ARM7)
GOOS=linux GOARCH=arm GOARM=7 go build -ldflags="-s -w" -o misterclaw ./cmd/misterclaw/

# CLI client
go build -ldflags="-s -w" -o misterclaw-send ./cmd/misterclaw-send/

# MCP server
go build -ldflags="-s -w" -o misterclaw-mcp ./cmd/misterclaw-mcp/

License

MIT