# psi

> Portable terminal coding agent written in ANSI C and Lua, shipped as a ~6.4 MB binary that runs on Linux, macOS, Windows, FreeBSD/OpenBSD and Haiku. Interactive TUI, REPL and one-shot modes, Lua extensions for commands and tools, append-only JSONL session trees, and providers for Anthropic, OpenAI Codex, OpenRouter or local Ollama models. MIT licensed.

- Page: https://vibetoolrank.com/tools/psi/
- Markdown: https://vibetoolrank.com/tools/psi.md
- Official: https://psicode.ai/
- Category: Coding Agents (CLI & Cloud) (https://vibetoolrank.com/best/terminal-agents/ · https://vibetoolrank.com/best/terminal-agents.md)
- Pricing: Free and open source (MIT). Bring your own model provider key or a local Ollama model; no psi paid plan listed.
- Free tier: Yes: MIT open-source binary, no psi account or card claimed (psicode.ai + GitHub, verified 2026-11-09)
- Last checked: 2026-11-09

## Agent test

- Not yet tested by VibeToolRank.

## Sources

- https://psicode.ai/
- https://github.com/siraben/psi
- https://news.ycombinator.com/item?id=50415406

Methodology: https://vibetoolrank.com/methodology/