Build a complete AI agent in 218 lines of Python. No frameworks, no complexity. Just clean code that shows exactly how agents work.
This tutorial demonstrates a working agent that can read, write, and edit files through natural conversation with Claude. Everything runs from a single Python file using uv's inline dependencies: no virtual environments, no pip installs, no dependency conflicts.
You'll understand how AI agents parse responses, execute tools, and maintain conversation context. The mechanics laid bare, without abstractions.
This code is based on the tutorial by Thorsten Ball in "How to Build an Agent" from ampcode.com. Thank you, Thorsten. Brilliant guide.
- Single-file execution.
- No virtual environment or manual dependency installation required (except for
uv). - The AI agent can:
- Read file contents.
- List directory contents.
- Edit existing files or create new ones.
- Interactive chat interface.
- Error handling and feedback.
- Logging of agent tool usage.
uvpackage manager (see installation instructions below)- Python 3.12 or higher (though
uvwill handle this automatically) - Anthropic API key (you can get one from Anthropic's Console)
uv is an extremely fast Python package manager that simplifies running Python scripts with inline dependencies.
It allows you to run Python scripts without needing to create a virtual environment or manually install dependencies.
To install uv::
curl -LsSf https://astral.sh/uv/install.sh | shpowershell -c "irm https://astral.sh/uv/install.ps1 | iex"After installation, verify it's working:
uv --version- Export your Anthropic API key:
export ANTHROPIC_API_KEY="your-api-key-here"- Run the agent:
uv run --python python3.12 main.pyThe agent leverages uv's inline dependencies handling from the script headers, so no manual dependency installation is needed.
This project is licensed under the MIT License - see the LICENSE file for details.