Misterclaw

👾🦀 MiSTerClaw — MCP Remote Control for MiSTer-FPGA

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

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(Badge suggestion: thanks, punkpeye.)

v0.8.1 adds validated native ZIP-member launches and an independent GBA2P profile. See the release notes and hardware-test limits, ZIP-member usage, and GitHub Releases for downloads and checksums.

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.

Arcade games

Arcade games are indexed from .mra descriptors and launched directly (initial support: thanks, stt); they are not represented by the MAME ZIP folder or a single system-wide RBF. Recursive canonical folders and _alternatives are supported on SD and USB. Generated _Organized views are omitted when canonical descriptors exist in the same root; an organized-only collection remains usable as a fallback. Byte-identical fallback descriptors are deduplicated, while different variants are retained. Counts describe indexed descriptors/variants, not unique game families. Cache schema v3 upgrades old v1/v2 Arcade and MAME entries in place while preserving unrelated cached systems; it does not require a full ROM rescan on upgrade.

A location-specific SD rescan also refreshes _Arcade, and existing SD/USB Arcade folders are merged rather than replaced. Location rescans now return status: pending immediately; poll systems.scanning until it becomes false. Existing results remain available during the refresh. Requests for overlapping scans or invalid locations fail explicitly. MRA launches validate the file, recycle virtual input devices, and report the descriptor's requested <rbf> in core_name; this response is not by itself proof that the FPGA finished loading.

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:

Downloads and supported platforms

Download executables from GitHub Releases, not from the source repository. The release workflow builds these targets:

Windows downloads are included in v0.8.0 and newer; older releases may not contain them. The daemon runs only on the MiSTer, not on Windows or macOS. On Linux/macOS, make the downloaded client executable with chmod +x <filename>.

For Windows, use the downloaded executable in PowerShell, for example:

.\misterclaw-send-windows-amd64.exe -H mister-fpga status

Point your MCP client's command to the absolute path of misterclaw-mcp-windows-amd64.exe; JSON paths must escape backslashes, for example C:\\Tools\\misterclaw-mcp-windows-amd64.exe.

The release workflow builds tagged releases (initial workflow: thanks, stt). New CI-generated releases include SHA256SUMS and build-metadata.json recording the source commit, compiler version and target inventory. Branch/PR/manual CI runs produce preview artifacts only. Publishing requires a version-tag push from main history and passing tests; maintainers must check release and licensing readiness before pushing a tag. Main ancestry is not itself proof of review approval. Adding CI does not create a new release.

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