Pi

What's included

Pi is a minimal open source coding agent harness maintained by Earendil Inc. and contributors. Instead of imposing a ready-made workflow, it gives developers primitives to build their own agent: extensions, skills, prompt templates, themes, custom sub-agents and plan modes. It connects to more than 15 model providers (Anthropic, OpenAI, Google, Azure, Bedrock, Mistral, Groq and others), allows switching models mid-session and keeps a tree-structured, shareable session history with automatic context compaction. It operates in four modes: interactive in the terminal, print/JSON for scripting, RPC and SDK for embedding in other applications. It installs via npm, pnpm or bun, with installers for Unix systems (curl) and Windows (PowerShell). It is free and open source under the MIT license.