C64U
MCP (Model Context Protocol) server for the Commodore 64 Ultimate Computer.
What is C64U?
C64U is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to mcp (model context protocol) server for the commodore 64 ultimate computer.
MCP (Model Context Protocol) server for the Commodore 64 Ultimate Computer.
This server falls under the Developer Tools category on MCPgee, the world's largest MCP server directory with 33,000+ servers.
Features
- MCP (Model Context Protocol) server for the Commodore 64 Ult
Use Cases
Maintainer
Works with
Installation
Manual Installation
npx c64uConfiguration
Configuration Details
claude_desktop_config.json
Performance
Response Metrics
Resource Usage
How to Set Up and Use C64U
The C64U MCP server bridges AI assistants with the Commodore 64 Ultimate (1541 Ultimate II+) cartridge, allowing Claude to control a real or emulated C64 over the network. It can write and execute BASIC programs, read and write RAM directly via DMA, play SID music and MOD files, mount floppy disk images, capture screenshots, and modify device configuration — all through natural language. It is aimed at retro computing enthusiasts and demoscene developers who want to use AI to write, debug, and run C64 software iteratively.
Prerequisites
- Python 3.10 or later installed
- uv package manager installed (pip install uv)
- A Commodore 64 Ultimate (1541 Ultimate II+) cartridge connected to your network
- The C64U device's IP address on your local network
- An MCP-compatible client such as Claude Desktop
Clone the repository
Clone the c64u-mcp-server repository to your local machine.
git clone https://github.com/xphileby/c64u-mcp-server.git
cd c64u-mcp-serverInstall dependencies with uv
Use uv to create a virtual environment and install all required Python dependencies.
uv syncFind your C64 Ultimate device IP address
Check your router's DHCP table or the device's network menu to find the IP address of your 1541 Ultimate II+ cartridge. The default in the code is 192.168.200.157 — replace this with your device's actual address.
Run the server to verify connectivity
Start the server with your device IP set via the C64U_URL environment variable and confirm it connects successfully.
C64U_URL=http://192.168.1.100 uv run python server.pyAdd to Claude Desktop config
Add the c64u server to your Claude Desktop configuration, pointing to the server.py file with your device's IP address.
{
"mcpServers": {
"c64u": {
"command": "uv",
"args": ["run", "python", "/path/to/c64u-mcp-server/server.py"],
"env": {
"C64U_URL": "http://192.168.1.100"
}
}
}
}C64U Examples
Client configuration
Claude Desktop config for the C64U MCP server with the device IP address configured via C64U_URL.
{
"mcpServers": {
"c64u": {
"command": "uv",
"args": ["run", "python", "/path/to/c64u-mcp-server/server.py"],
"env": {
"C64U_URL": "http://192.168.1.100"
}
}
}
}Prompts to try
Example prompts for writing programs, playing media, and controlling the C64 hardware.
- "Write a BASIC program that draws a colorful checkerboard pattern and run it on the C64"
- "Type HELLO WORLD on the C64 and take a screenshot"
- "Mount the disk image at /images/games.d64 and list its directory"
- "Play the SID file at /music/commando.sid on the C64"
- "Reset the C64 and then run a simple sprite animation program"
- "Read the current value of memory address $D020 (border color register)"Troubleshooting C64U
Connection refused or timeout when connecting to the C64U device
Verify the C64U_URL matches your device's actual IP address. Ensure the 1541 Ultimate II+ is powered on, connected to the same network, and has its network interface enabled in the device settings menu. Try pinging the IP from your computer first.
BASIC programs fail to execute or produce unexpected output
The enter_basic_program tool tokenizes BASIC before injecting it into memory. Ensure the program uses valid C64 BASIC V2 syntax. Some extended BASIC commands are not available unless the appropriate cartridge or extension is active.
uv sync fails with dependency errors
Ensure you are using Python 3.10 or later ('python --version'). If uv is not installed, run 'pip install uv' first. On some systems you may need to specify the Python version explicitly: 'uv sync --python python3.11'.
Frequently Asked Questions about C64U
What is C64U?
C64U is a Model Context Protocol (MCP) server that mcp (model context protocol) server for the commodore 64 ultimate computer. It connects AI assistants to external tools and data sources through a standardized interface.
How do I install C64U?
Follow the installation instructions on the C64U GitHub repository. Clone the repo, install dependencies, and add the server config to your AI client.
Which AI clients work with C64U?
C64U works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.
Is C64U free to use?
Yes, C64U is open source and available under the MIT license. You can use it freely in both personal and commercial projects.
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