pi-canvas

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🎨 Overview

pi-canvas brings the visual power of Claude Artifacts and v0.dev live UI previews directly to Pi Coding Agent sessions in your terminal.

Pi Agent is minimal by design, but software development is fundamentally visual. pi-canvas bridges the gap by spinning up an ultra-lightweight, zero-dependency local loopback web server (127.0.0.1) that receives diagrams, prototypes, and vector graphics pushed by the AI agent in real time via Server-Sent Events (SSE).

┌──────────────┐          render_canvas          ┌───────────────────────┐
│              │ ──────────────────────────────> │                       │
│   Pi Agent   │                                 │   pi-canvas (127.0.0.1)│
│  (Terminal)  │ <────────────────────────────── │      (SSE Stream)     │
└──────────────┘          user feedback          └───────────┬───────────┘
                                                             │
                                                             ▼
                                                 ┌───────────────────────┐
                                                 │   Browser Artifact    │
                                                 │ (Mermaid / HTML / SVG)│
                                                 └───────────────────────┘

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✨ Features

• ⚡ Live Hot-Reload via SSE: Instant push updates whenever Pi creates or refines an artifact.
• 📊 Native Mermaid 11 Diagrams: Flowcharts, sequence diagrams, class models, and state diagrams.
• 💻 Interactive HTML/Tailwind Sandbox: Isolated iframe stage to preview web components, forms, and pages.
• 🖼️ SVG Inspector: Vector graphics with dark-mode canvas integration.
• 📜 Session History Sidebar: Switch between artifacts generated during your session.
• 🔒 Loopback Security: Binds strictly to 127.0.0.1 and rejects external network requests.

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🚀 Installation

Via Pi Package Registry (Recommended)

pi install npm:pi-canvas

Direct from GitHub

pi install git:https://github.com/lleontor705/pi-canvas.git

From Local Clone

git clone https://github.com/lleontor705/pi-canvas.git
cd pi-canvas
npm install && npm run build
pi install ./

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📖 Usage & Commands

Slash Commands

Command	Description
/canvas	Starts the server (if not already running) and opens your browser.
/canvas stop	Stops the background loopback HTTP server.
/canvas clear	Clears all active artifacts from the sidebar.
/preview <path>	Previews an existing .html, .svg, .mmd, or .md file directly.

Agent Autonomous Tool (render_canvas)

When pi-canvas is installed, Pi gains the ability to display visual content autonomously:

// Example prompt:
"Design a sequence diagram showing our OAuth2 authentication flow with refresh tokens."

Pi will invoke render_canvas with:

• title: "OAuth2 Auth Flow"
• type: "mermaid"
• content: Flowchart syntax
• autoOpen: true

Your default browser automatically opens displaying the rendered diagram with dark mode styling!

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🏗️ Architecture & Development

# Clone the repository
git clone https://github.com/lleontor705/pi-canvas.git
cd pi-canvas

# Install dependencies
npm install

# Compile TypeScript
npm run build

Project Structure:

pi-canvas/
├── assets/
│   └── banner.svg         # SVG vector banner
├── dist/                  # Compiled ESM JavaScript & Type definitions
├── skills/
│   └── canvas/SKILL.md    # Pi Agent Skill instructions
├── src/
│   ├── index.ts           # Extension entry point & tool definitions
│   ├── server.ts          # Loopback HTTP + SSE server & embedded web app
│   └── types.ts           # Type definitions
├── .github/workflows/
│   ├── ci.yml             # Build & validation workflow
│   └── release.yml        # Tagged release & npm publish
├── package.json           # Pi manifest declaration
└── tsconfig.json          # TypeScript NodeNext configuration

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📄 License

MIT © Luis Leon