Pi Coding Agent is a minimal, open-source terminal coding harness that ships with four default tools and leaves most of the behaviour to extensions, skills and your own workflow.
Most AI coding agents are becoming bigger products. They add planning modes, subagents, permission layers, IDE integrations, background workers and increasingly elaborate orchestration around the model. Pi takes almost the opposite approach: the default agent starts with four basic tools — read, write, edit and bash — while most of the interesting behaviour is deliberately left to extensions, skills, packages and your own workflow.
This review is aligned with Pi v0.84.2, released on 14 August 2026. Mario Zechner created the project; it moved to Earendil Works in May 2026, which is why current packages use the @earendil-works scope rather than the older @mariozechner names. Pi has been changing quickly, so configuration and extension APIs deserve a version check before you standardise them across a team.
The catch is equally important: Pi gives you considerably more control than many coding agents, and correspondingly more responsibility. It does not provide a built-in security sandbox or the kind of permission system developers may expect after using Claude Code or similar tools. Below I cover the quickstart, architecture, model support, extensions, session model, security implications and where I think Pi fits among modern AI coding tools.
