Commodore 64 Ultimate Computer MCP Server

MCP (Model Context Protocol) server for the Commodore 64 Ultimate Computer REST API. This server exposes all Commodore 64 Ultimate Computer REST API endpoints as MCP tools.

Installation

cd c64u-mcp-server
uv sync

Configuration

Set the C64U_URL environment variable to your device's IP address:

export C64U_URL="http://192.168.200.157"

Default: http://192.168.200.157

Running the Server

uv run python server.py

Claude Desktop Configuration

Add to your Claude Desktop claude_desktop_config.json:

{
  "mcpServers": {
    "commodore64": {
      "command": "uv",
      "args": ["run", "--directory", "/path/to/c64u-mcp-server", "python", "server.py"],
      "env": {
        "C64U_URL": "http://192.168.200.157"
      }
    }
  }
}

Available Tools

About

• get_version - Get REST API version

Runners (SID/MOD/PRG/CRT)

• sidplay_file - Play SID file from device filesystem
• sidplay_upload - Upload and play SID file (base64)
• modplay_file - Play MOD file from device filesystem
• modplay_upload - Upload and play MOD file (base64)
• load_prg_file - Load PRG without executing
• load_prg_upload - Upload and load PRG (base64)
• run_prg_file - Load and run PRG from filesystem
• run_prg_upload - Upload and run PRG (base64)
• run_crt_file - Start cartridge from filesystem
• run_crt_upload - Upload and start cartridge (base64)

Configuration

• list_config_categories - List all config categories
• get_config_category - Get items in a category
• get_config_item - Get specific config item
• set_config_item - Set config item value
• batch_set_config - Set multiple config items
• load_config_from_flash - Restore config from flash
• save_config_to_flash - Save config to flash
• reset_config_to_default - Reset to factory defaults

Machine Control

• machine_reset - Reset the C64
• machine_reboot - Reboot Ultimate device
• machine_pause - Pause CPU via DMA
• machine_resume - Resume from pause
• machine_poweroff - Power off (U64 only)
• write_memory - Write hex data to C64 memory
• write_memory_binary - Write binary data to memory (base64)
• read_memory - Read C64 memory
• read_debug_register - Read debug register (U64)
• write_debug_register - Write debug register (U64)
• capture_screen - Capture C64 screen as PNG image
• type_text - Type text into keyboard buffer (supports special keys)
• send_key - Send a special key to keyboard buffer

Floppy Drives

• list_drives - List all drives and mounted images
• mount_disk_file - Mount disk from filesystem
• mount_disk_upload - Upload and mount disk (base64)
• drive_reset - Reset drive
• drive_remove - Unmount disk
• drive_on - Enable drive
• drive_off - Disable drive
• drive_load_rom_file - Load custom ROM
• drive_load_rom_upload - Upload custom ROM (base64)
• drive_set_mode - Change drive type (1541/1571/1581)

Streams (U64 only)

• stream_start - Start video/audio/debug stream
• stream_stop - Stop active stream

File Operations

• get_file_info - Get file metadata
• create_d64 - Create D64 disk image
• create_d71 - Create D71 disk image
• create_d81 - Create D81 disk image
• create_dnp - Create DNP disk image

Claude Skills

Skills are modular packages that extend Claude's capabilities with specialized knowledge. A .skill file is a ZIP archive containing:

• SKILL.md - Core instructions with YAML frontmatter
• references/ - Optional detailed documentation
• scripts/ - Optional executable code
• assets/ - Optional templates and files

Creating a .skill File

1. Navigate to the skill folder:

   cd claude-skills/c64-basic
   

2. Create a ZIP archive with .skill extension (create archive using folder contents, not the folder itself to make sure SKILL.md file located in archive root):

   # Windows PowerShell
   Compress-Archive -Path * -DestinationPath c64-basic.skill
   
   # Linux/Mac
   zip -r c64-basic.skill *
   

Adding Skills to Claude Desktop

1. Open Claude Desktop
2. Go to File → Settings → Capabilities → Skills
3. Click Add and select the .skill file
4. The skill will be available in all conversations

Available Skills

c64-basic (claude-skills/c64-basic/)

• Creates and runs C64 BASIC programs via MCP
• Handles tokenization, memory pointers, and keyboard buffer injection
• Trigger: Ask Claude to write C64 BASIC programs

API Reference

Based on: https://1541u-documentation.readthedocs.io/en/latest/api/api_calls.html