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.
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.
| Website | https://pi.dev |
|---|---|
| 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 (last checked 2026-10-21, source) |
| Free tier | Yes |
| Open source | Yes |
| License | MIT |
| Hands-on test | Test coming |
Machine-readable: Markdown · JSON dataset
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