Pi is a terminal coding agent that, according to Вам не нужен ещё один Claude Code: зачем Pi оставляет сборку агента пользователю, builds its Agent Harness from scratch rather than on top of an existing one. Its author, Mario Zechner, is described as having used Claude Code heavily in 2025 and being frustrated by how it was growing: features he did not need, and system instructions and tools that changed with updates, altering the model’s behaviour and breaking familiar workflows, while making it hard to see what the agent was sending into the context. He wanted a tool with understandable sessions, access to its internals and the ability to build a different interface over the same agent, and published Pi in the pi-mono repository.
Pi’s minimalism applies above all to this base: it is meant to be understandable and changeable enough that a user does not have to write an agent from scratch. It is nonetheless usable as-is, shipping with a terminal agent, basic tools and session management.
Capabilities
From the start Pi was a set of components rather than only a terminal command: pi-ai provides a single interface to different language-model providers, pi-agent-core handles agent execution, tool calls and state, pi-coding-agent assembles these into a coding assistant, and pi-tui provides terminal interface components. An application can embed the ready agent through an SDK, control it from another process over RPC, or take pi-agent-core and define its own interface and rules.
Its standard distribution deliberately has no built-in subagents, plan mode, task list or permission prompts. These are left to extensions, third-party packages or separately launched agent instances; a plan can be kept in an ordinary file or given a dedicated mode. Extensions can add tools, commands, event handlers and interface elements, skills and prompt templates hold reusable instructions, and packages distribute all of these together. By default Pi runs with the permissions of the process that started it and has no built-in isolation of the file system, processes, network or credentials, so isolation requires a separately configured container or other restricted environment.
Adoption & Ecosystem
Oh My Pi is a fork that uses Pi as its base and builds in a wider set of development tools. The overview recommends Pi where control over the agent’s design matters — an internal assistant, experiments with context, studying agent architecture or embedding the agent loop in a product.