# Pi

Minimal, highly extensible open-source terminal coding agent and agent harness from Earendil (created by Mario Zechner), customizable with TypeScript extensions, skills, prompt templates and shareable Pi packages.

- Website: https://pi.dev
- Hub: Vibe Coding
- Category: Terminal coding agent
- Best for: Developers who want a small coding agent they can reshape to their own workflow
- Pricing: Free (open source); bring your own API keys or sign in to a supported provider (checked 2026-10-21, source: https://pi.dev)
- Free tier: Yes
- Open source: Yes
- License: MIT
- Note: Source: pi.dev and github.com/earendil-works/pi (MIT, about 117k stars on 2026-10-21). Supports 15+ providers (Anthropic, OpenAI, Google, xAI, OpenRouter, Ollama and more) via API keys or OAuth, with interactive TUI, print/JSON, RPC and SDK modes and tree-structured, shareable session history. Deliberately skips built-in sub-agents and plan mode in favor of extensions. Pi 1.0 shipped with Pi Durable; the project moved from Mario Zechner's badlogic/pi-mono repo to Earendil in May 2026. A third-party natively compiled build, Pi-Bolt, was announced by OpenSec on Oct 21, 2026. Not yet tested or ranked.
- Hands-on test: coming
- Page: https://vibetested.app/tools/pi/