minipi

A lightweight coding agent, heavily inspired by pi. It is written in Python for better readability.

I wrote a detailed breakdown of the architecture in this blog: Building a coding agent from scratch.

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Features

Streaming responses
4 tools: read, write, edit, bash with a minimal sandbox
Project context loading (loads AGENTS.md and .agents/skills)
Support for commands (slash commands, e.g. /rewind, /resume, /permission)
Session persistence to ~/.mini-pi
Support for hooks, which are triggered at specific points in the agent lifecycle (e.g. input hook, pre tool call, post tool call)
Support for extensions (to expand the capabilities of the agent). This includes adding new tools, adding new AI vendors, and adding commands.
Auto compaction (or /compact <custom instructions>) to compact the older messages
Basic TUI
Support for steering and follow-ups

A few things:

Built-in support only for the OpenAI Chat Completions API. Tested only on fireworks.ai (with a few models), though more vendors can be added via extensions.
I tested it only on Ubuntu, though it should work on other OSes.
The sandbox supports only Linux.

System requirements: Python, uv and Node.js (for the TUI).
Run uv tool install mini-pi-agent. See PyPI here.
cd to the workspace you want to work in and run minipi.
Run /login fireworks fw_UIO.... The API key persists in raw form in ~/.mini-pi/auth.json.
Run /help to learn about more commands.