PiBun

A desktop app for the Pi coding agent. Chat with AI, run tools, manage projects — all in a native window.

Features

• Chat with Pi — streaming responses, thinking blocks, syntax-highlighted code, image paste
• Tool execution — watch Pi read files, write code, run commands in real time
• Projects — organize work by project, switch between them, browse past sessions
• Built-in terminal — full PTY terminal tabs alongside chat, scoped to each project
• Git integration — branch, status, changed files, inline diffs with syntax highlighting
• Session export — save conversations as HTML, Markdown, or JSON
• Themes — 5 built-in themes, follows system dark/light preference
• Plugins — sandboxed iframe plugins with a postMessage bridge
• Model switching — pick any model Pi supports, adjust thinking level on the fly
• Native desktop app — built with Electrobun, not Electron. Bun-native, fast, small.

Download

⬇ PiBun v0.1.1 for macOS (Apple Silicon) — 20 MB

Note: This build is unsigned. macOS will warn you on first launch. Right-click the app → Open → Open to bypass Gatekeeper. Linux and Windows builds coming soon.

Requires Pi installed: npm i -g @mariozechner/pi-coding-agent

Prerequisites

• Bun ≥ 1.2.21
• Pi installed and on your PATH (npm i -g @mariozechner/pi-coding-agent)
• macOS (Linux and Windows support in progress)

Quick Start

# Clone
git clone https://github.com/khairold/pibun.git
cd pibun

# Install
bun install
bun pm trust @biomejs/biome && bun pm trust esbuild

# Run in dev mode (3 terminals)
bun run dev:server    # terminal 1 — API server on :24242
bun run dev:web       # terminal 2 — Vite dev server on :5173
cd apps/desktop && PIBUN_DEV=1 npx electrobun dev  # terminal 3 — desktop app

Or run without the desktop shell:

bun run dev:server    # terminal 1
bun run dev:web       # terminal 2
# Open http://localhost:5173 in your browser

Build

bun run build                    # build all packages
bun run build:desktop            # unsigned desktop app
bun run build:desktop:signed     # signed + notarized macOS build

Architecture

┌──────────────┐     WebSocket       ┌──────────────┐     stdio/JSONL     ┌──────────┐
│  React UI    │ ◄──────────────────►│  Bun Server  │ ◄──────────────────►│ pi --rpc │
│  (Vite)      │                     │              │                     │          │
│  Chat, Tools │                     │  Bridge      │                     │ LLM API  │
│  Sessions    │                     │              │                     │ Tools    │
└──────────────┘                     └──────────────┘                     └──────────┘
         ▲                                  ▲
         └──────── Electrobun webview ──────┘

The server spawns pi --mode rpc as a subprocess and bridges JSONL events over WebSocket to the React frontend. Pi handles all the hard stuff — session persistence, model registry, API keys, tool execution, extensions. PiBun is the visual layer.

Package	Role
apps/server	Bun HTTP + WebSocket server, Pi subprocess manager
apps/web	React 19 + Vite + Zustand + Tailwind CSS v4
apps/desktop	Electrobun native wrapper (menus, file dialogs, notifications)
packages/contracts	Shared TypeScript types (no runtime code)
packages/shared	Shared utilities (JSONL parser)

Tech Stack

Runtime	Bun
Desktop	Electrobun
Frontend	React 19, Vite, Zustand, Tailwind CSS v4
Language	TypeScript (strict)
Agent	Pi via RPC subprocess

Contributing

Contributions welcome. The codebase is structured for AI agent development (deep modules, few files per domain) — see CLAUDE.md for conventions.

bun run typecheck    # type check all packages
bun run lint         # biome lint
bun run format       # biome format

License

MIT