Pi
Minimal, extensible open-source terminal coding agent and agent toolkit from Earendil, with a multi-provider LLM API, TypeScript SDK, RPC mode and installable extensions, skills and themes.
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About Pi
Pi is listed in our coding category and is aimed at builders. Minimal, extensible open-source terminal coding agent and agent toolkit from Earendil, with a multi-provider LLM API, TypeScript SDK, RPC mode and installable extensions, skills and themes. Pricing, as the maker states it: Open source (MIT); bring your own model provider or subscription. Maturity: Mature. We last checked the official link on 2026-10-18.
What is Pi?
Pi is a minimal, extensible agent harness from Earendil that you can run as an interactive terminal coding agent, in print/JSON mode for scripts, as an RPC server over stdin/stdout, or as a TypeScript SDK embedded in your own app. Pi 1.0 shipped together with Pi Durable, a durable conversation, task and document runtime.
It deliberately leaves out built-in sub-agents and plan mode: you add what you need with TypeScript extensions, skills, prompt templates and themes, bundled as Pi packages and shared over npm or git. It works with 15+ providers (Anthropic, OpenAI, Google, Bedrock, Mistral, Groq, xAI, OpenRouter, Ollama and more), can switch models mid-session, and stores sessions as branchable trees you can export to HTML or share as a gist.
Sources: the official README and our directory listing, checked 2026-10-18. Official site: pi.dev.
Who is Pi for?
Developers who want a small, hackable terminal coding agent they can reshape with their own extensions, and teams that want to embed an agent loop in their own product (the project cites OpenClaw as a real-world integration).
Pi at a glance
- Open source: Yes (MIT License)
- GitHub: earendil-works/pi · 116,878 stars (as of Oct 21, 2026)
Key features
- Interactive TUI, print/JSON, RPC and SDK modes
- 15+ model providers; switch models mid-session
- Extensions, skills, prompt templates and themes as npm or git packages
- Tree-structured sessions with HTML export and gist sharing
- AGENTS.md / SYSTEM.md context control and customizable compaction
Pi FAQ
What is Pi?
Pi is a minimal, extensible agent harness from Earendil that you can run as an interactive terminal coding agent, in print/JSON mode for scripts, as an RPC server over stdin/stdout, or as a TypeScript SDK embedded in your own app. Pi 1.0 shipped together with Pi Durable, a durable conversation, task and document runtime.
Who is Pi for?
Developers who want a small, hackable terminal coding agent they can reshape with their own extensions, and teams that want to embed an agent loop in their own product (the project cites OpenClaw as a real-world integration).
Is Pi free?
Pi's pricing, as the maker states it: Open source (MIT); bring your own model provider or subscription. Open-source tools are free to use, though you may still pay for model API usage or a hosted plan. Check the official site for current plans.
Is Pi open source?
Yes. Pi is released under the MIT License, according to its GitHub repository.
Does Pi sandbox the commands it runs?
No. Pi has no built-in permission system and runs with the permissions of the user who starts it; its docs recommend running it in a container or sandbox if you need stronger boundaries.
How do I install Pi?
Use the installer from pi.dev (curl -fsSL https://pi.dev/install.sh | sh, or the PowerShell script on Windows) or npm install -g @earendil-works/pi-coding-agent. It needs Node.js 22.19 or newer.
What are alternatives to Pi?
Similar tools include OpenAI Codex CLI, OpenHands, opencode, Tov, Chaterm and Gentle AI.
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