Companion App

Your canvas in the browser. Live-synced, interactive, on any device.

What is the Companion?

The Companion is a browser-based mirror of your Jetro workspace. It runs at localhost:17700 and gives you a full interactive canvas, sidebar, and terminal, all outside of your IDE.

It’s not a replacement for the extension. It’s a second screen for your workspace.

How it works

The extension runs a lightweight local server on port 17700. When you open the Companion in your browser:

  1. Initial load. The Companion fetches your projects, canvases, portfolios, datasets, and lists.
  2. Live sync. Every change streams in real-time. Create an element in your IDE, it appears in the browser instantly. Move a node in the browser, it syncs back.
  3. Auto-save. Changes in the Companion are saved to disk automatically.

No cloud. No external servers. Everything runs on your machine.

What you can do in the Companion

  • Browse your workspace. 5 sidebar tabs: Search, Projects, Library, Portfolio, Market
  • Open and edit canvases. Drag nodes, zoom, pan, connect elements, delete, duplicate (Cmd+D), copy/paste
  • Create new canvases. Start from scratch or use templates
  • View portfolios. NAV, returns, holdings, benchmark comparison at a glance
  • Query datasets. Run SQL against your local database from the browser
  • Upload files. Drop PDFs, spreadsheets, or any document into a project
  • Present full-screen. Hide the sidebar, zoom into your canvas, share your screen

Working independently with CLI agents

While the Companion mirrors what your IDE agent builds, you can also use it as a standalone canvas viewer paired with a CLI-based AI agent.

Run a CLI agent in your terminal. It uses Jetro’s tools to build elements on your canvas, and the Companion displays everything in real-time.

Compatible CLI agents:

  • Claude Code by Anthropic. Discovers Jetro’s tools automatically.
  • OpenAI Codex CLI by OpenAI. Point it at Jetro’s tool config.
  • Gemini CLI by Google. Works with Jetro’s tool discovery.
  • Any compatible agent that supports the Model Context Protocol.

This means you can have the Companion open in your browser while a CLI agent works in your terminal. No IDE needed for the AI part, just the extension running in the background to serve the workspace.

When to use the Companion

  • Presentations. Full-screen canvas in the browser, no IDE chrome
  • Multi-monitor. IDE on one screen, canvas in the browser on another
  • Mobile review. Check your canvas on a tablet or phone (responsive layout)
  • Collaboration. Multiple people viewing the same canvas simultaneously with live sync
  • CLI workflows. Pair with Claude Code or any CLI agent for a terminal-first experience

Opening the Companion

From your IDE, run the command:

Jetro: Open Companion

Or navigate to http://localhost:17700 in any browser while the extension is running.