Get started

The fastest way to understand Muxy extensions is to make one run. This page takes you from nothing to a live extension in about two minutes, then points you at the rest of the docs.

An extension is an npm + Vite project that Muxy loads on launch. It can add UI (tabs, panels, popovers, topbar and status-bar items), register palette commands, react to workspace events, and — with permission — drive the same verbs the muxy CLI exposes.

Run your first extension

In Muxy, open the Extensions modal → Create, pick a folder, and name it my-extension. Muxy scaffolds the vanilla starter kit (a Hello panel, a panel-toggle command icon that may sit in the title bar or on the optional right rail, and a command) and loads it as a dev extension automatically.
Build it so Muxy has a dist/ to read:
```
cd my-extension
npm install
npm run build    # produces dist/ — the folder Muxy loads
```
npm run dev starts Vite's dev server for fast iteration, but Muxy loads the built dist/ folder, so run npm run build (and Reload) to see changes in the app.
Click Reload in the Extensions modal, then press ⌘⇧H (or use the sparkles icon in the title bar, or on the right-hand extension rail if Show Extension Icon Rail is on — this starter icon is a panel toggle, so it may sit on the rail). The Hello panel toggles — that's your extension running.

Dev extensions show a DEV badge. Edit the source, then Reload to see changes. Remove from Muxy on the detail page unloads it without touching your folder on disk.

Coding-agent skill

Scaffolded extensions already include the muxy-extension skill (in .claude/skills/ and .agents/skills/) so coding agents follow Muxy's conventions. To add it to an existing project, install it from skills.sh:

npx skills add github.com/muxy-app/muxy/tree/main/Muxy/Resources/skills/muxy-extension

Make it your own

The starter kit is a working example of the most common pieces. To build something real:

Declare what it does in package.json under the muxy key — see Manifest.
Add UI with Tabs, Panels, Popovers, Sidebars, Topbar, and Status Bar items, or run logic from Palette Commands and Scripts.
Work with the workspace through Events, Git, Files, HTTP, and Settings.
Request the minimum you need — see Permissions.

When you want the full picture of how extensions load and run, read the Overview.

Publish it

Ready to share it with everyone? Contributing an extension walks through the fork → develop → validate → pull request flow.