Pi Agent

Pi is an open-source, terminal-first coding agent and customizable agent harness. It lets developers use natural-language prompts to analyze, write, and modify code, while retaining control over the agent’s tools, prompts, workflow, interface, and model provider.

Pi supports interactive terminal use, print and JSON output for scripting, a stdin/stdout RPC mode, and an SDK for embedding the agent in other applications. It can connect to multiple hosted and local model providers, and users can switch models during a session.

The core is intentionally minimal. Developers extend it with TypeScript extensions, skills, prompt templates, themes, and packages distributed through npm or Git. Project instructions, skills, and context-management behavior can be customized per repository, including automatic context compaction and dynamic retrieval. Session history is stored as a navigable tree that can be branched, exported, or shared.

Pi is suited to developers and teams that want a coding agent they can adapt to existing toolchains and operating practices rather than a fixed agent workflow.