Vercel announced Box Mount in private preview on October 28. It synchronizes a Box folder with a directory in Vercel Sandbox, allowing a process in the sandbox to read and write files using ordinary filesystem operations.
The security boundary matters
- The mount must be unmounted before the sandbox stops so written changes can be synchronized back to Box.
- Vercel's example separates the synchronization process from the agent user so Box credentials are not placed in the agent workspace.
- The feature requires private-preview access from Box and follows Vercel Sandbox setup instructions.
The preview is designed for workflows such as reviewing a synthetic contract and saving a result to Box. Do not treat the sandbox as permission to expose credentials or unrestricted files to an agent.
Check the official documentation and access requirements before designing a production workflow around a private-preview capability.