fragletc

Run code fragments in 90+ language containers. Ships with built-in MCP server.

fragletc runs code fragments in isolated containers across 90+ languages. It ships as a single binary with built-in MCP server support for AI tool integration.

Prerequisites

Docker is required. fragletc uses Docker to run code in isolated containers.

Verify Docker is working:

docker run --rm hello-world

Quick Install

curl -fsSL https://raw.githubusercontent.com/ofthemachine/fraglet/main/install.sh | sh

This downloads the latest release for your platform, verifies the checksum, and installs to ~/.local/bin.

To install to a different location:

FRAGLETC_INSTALL_DIR=/usr/local/bin curl -fsSL https://raw.githubusercontent.com/ofthemachine/fraglet/main/install.sh | sh

Verify

fragletc --help
fragletc --vein=python -c 'print("hello from fraglet")'

MCP Server Setup

fragletc includes a built-in MCP (Model Context Protocol) server. Run it with:

fragletc mcp

This starts the server over stdio, compatible with any MCP client.

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "fraglet": {
      "command": "fragletc",
      "args": ["mcp"]
    }
  }
}

Restart Claude Desktop after saving.

Cursor

One-click install:

Install fraglet in Cursor

Manual setup — add to .cursor/mcp.json (project-level) or ~/.cursor/mcp.json (global):

{
  "mcpServers": {
    "fraglet": {
      "command": "fragletc",
      "args": ["mcp"]
    }
  }
}

MCP Tools

The MCP server exposes two tools:

Manual Install

Download the binary for your platform from GitHub Releases, then:

chmod +x fragletc-*
mv fragletc-* /usr/local/bin/fragletc

Build from Source

Requires Go 1.24+:

git clone https://github.com/ofthemachine/fraglet.git
cd fraglet
make install

Or directly:

go install github.com/ofthemachine/fraglet/cli@latest

Troubleshooting

command not found: fragletc

The install directory is not in your PATH. Add it:

export PATH="$HOME/.local/bin:$PATH"

Add this line to your ~/.zshrc, ~/.bashrc, or equivalent.

Docker connection errors

Ensure Docker is running:

docker info

On Linux, your user may need to be in the docker group:

sudo usermod -aG docker $USER
# Then log out and back in

Container image pull failures

If you're behind a firewall or proxy, Docker may not be able to pull images. Pre-pull a vein to test:

fragletc refresh python

MCP server not connecting

1. Verify the binary path is absolute or in PATH
2. Check the JSON syntax in your MCP config file
3. Restart your MCP client (Claude Desktop / Cursor) after config changes
4. Test the server manually: echo '{}' | fragletc mcp should produce JSON-RPC output