Access models
Online and offline access
Both models include agent connections. They differ in where the workspace runs and what remains available without the internet.
Platform availability
- Web: Available now in your browser.
- Mac and Windows: Beta packages, with verified downloads for signed-in members.
- iOS: Use the web workspace in Safari. Native iOS app: future availability.
Mac and Windows downloads
Sign in for verified downloads
Choose where your workspace lives
| Feature | Online | Local |
|---|---|---|
| Use on your phone | Browser, no install | Use online mode on your phone |
| Data location | Encrypted account storage | Encrypted on your computer |
| Records, rules and suggestion review | Browser | Browser on that computer |
| Agent connections | Remote MCP with OAuth or scoped tokens | Loopback MCP for compatible local apps |
| Browser closed | Approved agents keep access | Agents keep access while local runtime is running and unlocked |
| No internet | Connection required | Records, rules, imports, exports and compatible local agents |
| Web providers | Supported remote MCP connectors | Network and a reachable endpoint required |
| Move your data | Explicit password-encrypted export and import | |
A remote provider cannot reach a computer's loopback address. Local file watching, credential fills and model inference belong to the separate developer runtime; they are not part of this browser workspace. Online data is served by Castellan's hosted broker. Existing local data is never uploaded automatically.
Open workspace