Cosmux

AI coding assistant widget for local development - powered by Claude.

Installation

``bash
npm install -D cosmux
`

Vite

`typescript
// vite.config.ts
import { defineConfig } from 'vite'
import react from '@vitejs/plugin-react'
import { cosmux } from 'cosmux/vite'

export default defineConfig({
plugins: [
react(),
cosmux()
]
})
`

Add your API key to .env:

`bash
ANTHROPIC_API_KEY=sk-ant-...
`

Run npm run dev - the widget appears in the bottom-right corner.

Next.js

`javascript
// next.config.mjs
import { withCosmux } from 'cosmux/next'

export default withCosmux({
// your existing config
})
`

For App Router, create a widget component:

`tsx
// components/CosmuxWidget.tsx
'use client'

import { useEffect } from 'react'

export function CosmuxWidget({ port = 3333 }: { port?: number }) {
useEffect(() => {
if (process.env.NODE_ENV !== 'development') return

;(window as any).__COSMUX_CONFIG__ = { serverUrl: http://localhost:${port} }

const script = document.createElement('script')
script.src = http://localhost:${port}/static/inject.js
script.async = true
document.body.appendChild(script)

return () => { script.remove() }
}, [port])

return null
}
`

Then add to your layout:

`tsx
// app/layout.tsx
import { CosmuxWidget } from '@/components/CosmuxWidget'

export default function RootLayout({ children }) {
return (


{children}



)
}
`

Configuration

$3

`typescript
cosmux({
port: 3333, // Server port (default: 3333)
autoStart: true, // Auto-start server (default: true)
injectWidget: true, // Inject widget script (default: true)
workspace: './', // Workspace path (default: cwd)
})
`

$3

`javascript
withCosmux(nextConfig, {
port: 3333,
autoStart: true,
workspace: './',
})
`

CLI

`bash
npx cosmux serve
npx cosmux serve --port 4000
`

Requirements

- Node.js 18+
- Anthropic API key (or Claude Max subscription)

How it works

1. npm install downloads a platform-specific binary
2. The plugin starts the Cosmux server automatically
3. A widget script is injected into your HTML
4. Press Cmd+K (or click the button) to open the assistant

Uninstall

`bash
npm uninstall cosmux
``

License

MIT