Pi Web UI

A web UI for Pi coding agent. Runs as a Pi extension inside your existing Pi process — no separate server needed.

Forked from deflating/tau. Thanks to the original author for building the foundation. Renamed to pi-web-ui with significant changes including single-session scope, removed auth, redesigned sidebar.

What it does

Pi Web UI connects to your running Pi session and gives you a browser interface. Same session, same messages, same tools — just a different screen. Type in the terminal or the browser, both stay in sync.

• Real-time streaming — messages, tool calls, and thinking blocks
• React UI — Vite, Tailwind, shadcn/ui, AI Elements
• Markdown rendering — Streamdown for code blocks, math, Mermaid
• No extra process — the Pi extension is the server

Install

Install from GitHub:

pi install git:github.com/kkkiio/pi-web-ui

Or from npm:

pi install npm:@kkkiio/pi-web-ui

Usage

1. Start Pi in your terminal
2. Type /webui — the extension uses the execution context to resolve the URL, enable advanced features, and open the browser

The server starts automatically when a Pi session begins and shuts down when the session ends.

Features

Chat

• Streaming text and thinking/reasoning blocks
• Tool call display with expand/collapse
• Image attachments with paste, drop, and preview
• Message editing via navigate_tree (requires /webui command context)
• Follow-up messages while the agent is streaming

Model & Thinking

• Current model label and searchable model picker
• Thinking level cycle button
• Context-window visualization and compact suggestion

Sessions

• Sidebar with active session info and history browser
• Session rename, search, and favourites

Commands & Settings

• Command palette: compact, export HTML, session stats, tool toggle
• Light, dark, and system theme modes

Configuration

Environment variables (set before starting Pi):

Variable	Default	Description
PI_WEB_UI_PORT	3001	Server port
PI_WEB_UI_HOST	127.0.0.1	Bind address
PI_WEB_UI_DISABLED	0	Set to 1 to disable
PI_WEB_UI_STATIC_DIR	(bundled)	Override static files path
PI_CODING_AGENT_DIR	~/.pi/agent	Override Pi config directory
PI_CODING_AGENT_SESSION_DIR	(derived)	Override Pi session storage directory

Or in ~/.pi/agent/settings.json:

{
  "pi-web-ui": {
    "port": 3001,
    "host": "127.0.0.1"
  }
}

Pi Web UI follows Pi's PI_CODING_AGENT_DIR and PI_CODING_AGENT_SESSION_DIR overrides when reading settings and session history.

Start / Stop

/webui-stop     Stop the server
/webui-start    Start it again

To prevent auto-start:

PI_WEB_UI_DISABLED=1 pi

Security

Pi Web UI binds to 127.0.0.1 by default — accessible only from your local machine. For remote access, use tailscale serve or a reverse proxy with TLS. There is no built-in authentication; it's unnecessary for local-only access and insecure over cleartext.

How it works

Pi Web UI is a Pi extension. When Pi starts a session, the extension starts an HTTP + WebSocket server inside the Pi process. The extension subscribes to Pi events and forwards them to the browser. Commands from the browser execute via the extension API using the ExtensionContext that Pi provides.

graph LR
    A[Pi TUI<br/>terminal] <-->|Pi events| B[Pi Process<br/>pi-web-ui extension]
    B <-->|HTTP + WS :3001| C[Browser]

Development

git clone https://github.com/kkkiio/pi-web-ui.git
cd pi-web-ui
npm install
npm run build:web
PI_WEB_UI_STATIC_DIR=$(pwd)/dist pi

For frontend development, run Pi in one terminal, then:

npm run dev:web

Open http://localhost:4444; Vite serves the React UI and proxies /api and /ws to the extension on localhost:3001.

License

MIT