---
type: "GlossaryTerm"
title: "Pi Coding Agent"
description: "The Pi Coding Agent is an open-source, deliberately minimal agent harness for software development, created by Mario Zechner and released in late 2025. Where co"
resource: "https://www.contextstudios.ai/glossary/pi-coding-agent"
language: "en"
tags: ["tech"]
generated:
  by: "process:contextstudios-md/1"
  at: "2026-10-08T20:44:55.257Z"
status: "stable"
---

# Pi Coding Agent

The Pi Coding Agent is an open-source, deliberately minimal agent harness for software development, created by Mario Zechner and released in late 2025. Where commercial coding agents keep piling on features, Pi settles for four core tools (read, edit, write, shell), a system prompt under 1,000 tokens, and full observability of every step: plans and actions stay visible as plain-text files instead of disappearing into a sub-agent black box. Pi can extend itself through TypeScript extensions; missing features such as sub-agents or plan mode are installed on demand rather than shipped by default. It runs in four modes (interactive, print/JSON, RPC, SDK) and locks teams into no model provider, because it works with any provider that accepts your own API key. Example Terminal-Bench: in early 2026, Pi paired with Claude Opus 4.5 landed just behind Terminus — remarkable because the lean harness did not yet have context compaction at that point. In terms of terminology, it is clearly distinct from Inflection AI's chatbot "Pi" (2018/2023), a completely different product, and also from proprietary harnesses such as Claude Code: the Pi Coding Agent is neither a company product nor tied to a subscription, but rather a hackable, auditable harness under an open-source licence, built for developers who want to rebuild their agent rather than subscribe to it.