Box Mount now runs in Vercel Sandbox

Box Mount syncs a Box folder with a directory inside a sandbox, so an agent can work with Box files using standard filesystem calls. According to Vercel, anything the agent writes ends up in Box, and the developer should unmount before stopping the sandbox so that data is kept after the sandbox is deleted.

Vercel's contract-review example runs an agent in Vercel Sandbox that uses AI Gateway to review a synthetic contract and saves the review back to Box. The sync process and the agent run as separate sandbox users, which keeps the Box credentials out of the agent's workspace.

Box Mount is in private preview. Developers need to request access from Box and then follow the Box Mount documentation to set it up in Vercel Sandbox.

Agents that need to read inputs from or save outputs to Box can use plain file operations instead of a separate Box integration inside the agent code.

Unmount the Box folder before stopping a sandbox, because the write-back to Box depends on that step. Access is limited to the private preview, so teams will need to request it from Box first.