What Pi Coding Agent Is: Mario Zechner's Minimal Open-Source Coding Agent
Pi is not another bloated black box. It is a minimal terminal harness with only 4 base tools, fully extensible through TypeScript.
Read originalPi is a harness, not a model
Pi (pi-coding-agent) is Mario Zechner's open-source terminal coding agent harness — the layer around a model that decides how tools are exposed, files are read, commands are run and sessions branch.
Four atomic tools
Pi ships with only read, write, edit and bash. No forced plan mode, no auto-dispatched sub-agents. Every step is visible, interruptible and replayable in your terminal.
Four run modes
Interactive TUI, print/JSON one-shot CLI, JSON-RPC over stdin/stdout, and a native TypeScript SDK for embedding.
Hub
Pi Agent Hub · Quickstart · Directory card.
FAQ
What is Pi Coding Agent?
A minimal open-source terminal coding harness by Mario Zechner with 4 base tools, fully customizable via TypeScript extensions and Skills.
How is it different from Claude Code?
Claude Code is Anthropic's closed hosted product; Pi is MIT-licensed, transparent and embeddable.
Topic hub
Pi Agent
Mario Zechner's minimal open-source coding agent: 4 base tools, TS extensions, skills & SDK embedding.
Topic hub
Claude Code Ecosystem
Anthropic's official terminal agent (closed), with a largely open Skills/hooks/MCP ecosystem — the benchmark.
Made by Laojin · AI that ships
365SkillAn agent-skills lab: 13 in-house skills
365Skill is our public lab for agent skills: a standard SKILL.md format, a deny-by-default publish policy, and an evals harness. It holds 13 original 365 skills — 11 public and 2 internal. Apache-2.0 — star it, install it, file issues.
More from Laojin: Sellenca · 365AIOrg · AllModelsAPI · 365Loopa · 365 Ops
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