Pi Coding Agent

Pi runs in a loop with full tool-calling access — read, write, edit, bash — and surfaces four modes: interactive TUI, print/JSON for scripting, RPC, and an SDK for deeper integration. Sessions are stored as trees, so you can rewind to any prior message, fork from that point, and share the entire branch as a rendered URL. The extension and skills system lets you load context on-demand rather than stuffing everything into the system prompt at startup — which the docs describe as a deliberate choice to stay token-efficient. Where Pi stops short is also deliberate: sub-agents and plan mode are not included by default, so teams that need multi-agent parallelism or structured planning build or install extensions themselves. That tradeoff keeps the core minimal, but it means the complexity budget shifts from the tool to you.