MyCoder-Mini

MyCoder-Mini is an open-source, MIT-licensed experiment by Ben Houston in building a minimalist agentic coder. It is a TypeScript command-line tool that sends a user's prompt to Anthropic's Claude and lets the model run shell commands until the task is finished. The author describes it as less than 200 lines of code in a single file.

What It Is

MyCoder-Mini is a command-line agent loop built on the Anthropic Claude SDK with native tool calling. The user supplies a prompt, Claude decides which shell commands to run, and the tool returns the results to the model. The author's blog post presents it as a way to show the foundational principles of agentic coding, and the README points to the full MyCoder project for a full-featured agentic coder.

How the Agent Loop Works

The tool exposes two tools to the model: shellCommand, which runs shell commands, and finished, which signals completion. The loop repeats until Claude calls finished. Shell commands have a 10-second timeout to prevent hangs, and Claude's thinking process and command execution are displayed in real time. The blog post's example uses the claude-3-7-sonnet model.

Setup Path

Users clone the repository, run npm install and npm run build, and can link the tool globally with npm link. An ANTHROPIC_API_KEY environment variable is required. The tool is then run as mycoder-mini "your prompt", or via npm start or Node directly.

Documented Limitations

The blog post lists these limitations: commands run synchronously, so long-running or interactive CLI processes are not handled; there is no browser integration; and the toolset is limited to shell commands.