Pi 1.0: Open-Source Terminal AI Coding Agent Harness
Earendil shipped Pi 1.0 on 1 October 2026, describing it as a hardened, minimal, extensible agent harness that you can make your own.
Tool Overview
Features, steps and FAQ below
Features
- ✓ Earendil says hundreds of thousands of people use Pi every week, and that 1.0 is a stable version people and businesses can depend on after months of feedback
- ✓ Pi 1.0 adds Codemode: native support for MCP plus non-LLM models like Jev and image models
- ✓ It adds extension support for virtual models, deferred tool loading, cache warming for Anthropic models and mid-conversation system messages
- ✓ On the interface side it adds a new TUI theme and makes full-screen mode the default
- ✓ It also ships Pi Durable, an experimental package for building long-running agentic applications; Pi is MIT-licensed with code on GitHub and docs at pi.dev
How to Use
- Install on macOS/Linux with curl -fsSL https://pi.dev/install.sh | sh, or on Windows with irm https://pi.dev/install.ps1 | iex
- Start Pi in the directory where you want it to work and run /login to connect a subscription or API key for a built-in provider
- Customize Pi with extensions, skills, prompt templates and themes, and bundle them as Pi packages shared via npm or git
- For long-running applications, install packages such as @earendil-works/pi-durable to build with Pi Durable
FAQ
What is Pi 1.0?
An open-source AI coding agent harness released by Earendil on 1 October 2026, which Earendil describes as a hardened, minimal, extensible agent harness that you can make your own.
What is new in Pi 1.0?
Earendil lists Codemode (native MCP and non-LLM model support), virtual-model extension support, deferred tool loading, cache warming for Anthropic models, mid-conversation system messages, a new TUI theme and full-screen by default.
How do I install Pi?
Earendil says run curl -fsSL https://pi.dev/install.sh | sh on macOS/Linux, or irm https://pi.dev/install.ps1 | iex on Windows.
Is Pi open source?
Earendil says both Pi 1.0 and Pi Durable are MIT-licensed, with code at github.com/earendil-works/pi and docs at pi.dev.
What is Pi Durable?
Earendil says it is an experimental package shipped alongside 1.0, a new substrate for building long-running agentic applications that shares Pi's principles of minimalism and malleability.