Workshop Extension

Building Agent Harness
with Pi

The Minimalist Agent Harness — pi.dev

UCSI University — Agentic AI Workshop

29th July 2026

Presented by Jarod Tan

What is Pi?

Open-source, terminal-based AI agent harness — minimal, extensible, model-agnostic.

Terminal-native

No GUI. No SaaS. Runs in your shell.

MIT Licensed

Full source. Fork it. Own it.

Model Agnostic

15+ providers. Self-hosted OK.

Created by Mario Zechner (libGDX) · Stewarded by Earendil Inc. · 79k+ ⭐ on GitHub

Born from frustration with Claude Code's feature creep. Philosophy: ship less, let users build. 4 built-in tools, everything else is an extension.

Architecture

4 tools + transparent agent loop + tree sessions.

~ Run

Shell commands

/ Search

Read files, glob

> Write

Create/edit files

? Ask

Multi-turn chat

User prompt ↓ Think → Act → Observe → Decide ↻ loop or stop

Tree sessions: fork, checkpoint, merge — like git for agents. Sessions are files on disk. Commitable, shareable, diffable.

Why It Matters

Pi is a reference implementation of agent harness philosophy in production.

OpenClaw runs on Pi's SDK

Production agent platform built on Pi. Validates the pattern: product on harness, harness on model.

Blueprint for platform builders

Minimal core + extension API is the architecture that scales from CLI to platform.

Security & compliance ready

Self-hosted models, local-first, no SaaS. Aligns with zero-trust requirements.

80k ⭐ in 10 months

Fastest-growing dev tool. Ecosystem of skills, packages, and extensions.

First, Install OpenCode

We'll build with Pi, but we'll use OpenCode to do it. Install it first.

$ curl -fsSL https://opencode.ai/install | bash

No account needed. Open source. MIT licensed.

opencode.ai

Getting Started

$ npm install -g @earendil-works/pi-coding-agent

pi.dev Packages

Extend Pi with community packages — install from npm, use immediately.

pi-free

Free model providers — Kilo, Cline, OpenRouter, LLM7. No API keys needed.

↳ pi install npm:pi-free

pi-subagents

Delegate to child agents — chains, parallel review, background workers, oracle oversight.

↳ pi install npm:pi-subagents

pi-web-access

Web search, URL fetch, GitHub clone, YouTube & PDF understanding.

↳ pi install npm:pi-web-access

Browse all packages at pi.dev/packages

Try OpenCode

The AI coding assistant I use every day — and the tool that built this workshop.

Get 55 free conversations

opencode.ai/go?ref=HSZ7VKR1DY

Terminal-native AI agent. Open source. Model agnostic. Build your own agent harness.

Resources

📖 pi.dev · 🐙 github.com/earendil-works/pi · 💬 discord.gg/3cU7Bz4UPx

You don't need a heavy platform
to build agents.

Build your harness. Own your tools. Choose your models.