Use Muse Code inside Cursor

What the Helicon extension is

Helicon is an unofficial, open source side panel for the muse CLI. It runs muse serve for the folder you have open and gives you a GUI over it, so Muse Code stays the agent with the same models, tools and approval rules as in the terminal.

• Threads as tabs: the threads you have open in this folder sit across the top of the panel.
• Approvals you can read: the exact command or edit before it runs, then allow or deny it.
• The files each thread changed, with line counts, one click from opening in the editor.
• History: every earlier thread in the folder, searchable and grouped by day, including the ones you started in the terminal.
• Monitors: a thread that is watching a build or a pull request's checks says so, with a Stop button.
• Plan usage: your 5-hour and weekly windows, and what each thread would have cost at API rates.

Why Cursor installs it from Open VSX

Cursor, Windsurf and Antigravity install extensions from Open VSX, an open registry for VS Code extensions, rather than from the VS Code Marketplace. Helicon is published to both. Every release ships the same build under the same ID, harjjotsinghh.helicon, so Cursor gets the same version as VS Code.

What you need first

• The muse CLI, installed and signed in once with muse login. The extension uses that login and never asks for an API key.
• A Muse Code plan, or pay-as-you-go billing on Meta's Model API. The free Muse app doesn't include Muse Code.
• A current release of Cursor, Windsurf or Antigravity. The extension runs on the editor's own Node runtime and needs Node 22 or newer.

If muse --version does not answer in a terminal, fix that first. The muse CLI not found guide covers the usual causes.

Install it in Cursor

1. 1Open the Extensions view with Cmd+Shift+X on macOS or Ctrl+Shift+X on Windows and Linux.
2. 2Search for "Helicon".
3. 3Pick Helicon by harjjotsinghh and click Install.

Windsurf and Antigravity work the same way: open the Extensions view and search for Helicon.

If the search does not show it, download the .vsix from Open VSX and run Extensions: Install from VSIX from the Command Palette.

Open the panel

Click the Helicon icon in the activity bar, or press Cmd+Alt+H on macOS or Ctrl+Alt+H on Windows and Linux. The panel opens on the folder you have open. New threads open as tabs, and the clock icon shows every earlier thread in the folder.

For every project at once, run Helicon: Open Full Helicon in Editor from the Command Palette. It opens the full app, sidebar and all, in an editor tab.

Helicon and Cursor's own agent

Helicon does not replace or hook into Cursor's agent. It is a separate panel for Muse Code, on your own Muse Code plan, and both can be open at once. The same goes for the built-in agents in Windsurf and Antigravity.

Remote-SSH and WSL

In a Remote-SSH or WSL window, the extension runs on the remote side, next to your code and its muse install, and the editor forwards the port for you.

• Install the muse CLI on the remote machine, or inside the WSL distribution, and run muse login there once.
• The Muse login on the remote side is the one the panel uses.
• Check with muse --version in the integrated terminal, which already runs on the remote side.

Recommend it to your team

Add Helicon to the repository's .vscode/extensions.json, so the editor suggests it to anyone who opens the folder without it installed.

{ "recommendations": ["harjjotsinghh.helicon"] }

The ID is the same on Open VSX and the VS Code Marketplace, so one file covers teammates on Cursor and on VS Code. Each person still needs their own muse CLI, muse login and Muse Code plan.

Try it before you install

Try the full app in your browser first. It runs on sample data, so nothing needs to be installed and no Muse login is involved.