Pi Agent
Pi is a minimal open-source coding agent for the terminal: four tools, a system prompt under 1,000 tokens, and your own model keys.
Score 35CLIFree / BYO keyOpen source
Project status. Pi is MIT-licensed and written in TypeScript. It was created by Mario Zechner and is now developed under Earendil Works at github.com/earendil-works/pi, which carried 89.0k stars when this page was last checked on 13 August 2026. The harness deliberately ships without MCP, plan mode or sub-agents; extensions supply those instead. It does not appear on the Terminal-Bench 2.0 or 2.1 leaderboards, so the score here rests on architecture review rather than a published benchmark run.
| AgentRanks score | 35 |
|---|---|
| Workflow type | CLI |
| Pricing | Free agent |
| Open source | Yes |
| Best fit | minimal-token terminal use |
Best Pi Agent stacks
Model pairings ranked by combined ARscore.
| # | Stack | ARscore | Context | Cost | Best fit |
|---|---|---|---|---|---|
| 1 | Pi Agent + DeepSeek V4 FlashOS CLI agent | 27.7 | 1M | $0.14/$0.28 | minimal-token terminal use |
| 2 | Pi Agent + DeepSeek V3.2OS CLI agent | 24.5 | 128K | $0.25/$0.38 | minimal-token terminal use |
| 3 | Pi Agent + Qwen 3.6OS CLI agent | 22.8 | 128K | $0.3/$0.6 | minimal-token terminal use |
Alternatives
Nearby agents by workflow or openness.
Claude Code
deep terminal workflows and complex multi-step refactors
score 86 / CLI/Desktop
ChatGPT Codex
ChatGPT Codex workflows, terminal automation, and CI-style editing
score 84 / CLI/Desktop
ClineOS
MCP-heavy VS Code workflows and bring-your-own-model setups
score 61 / Extension
AiderOS
git-native terminal editing and experienced open-source users
score 60 / CLI