The AI Agent Sandbox You Already Have: A Drive Letter

Description and use

Using a Windows drive letter as an isolated sandbox for AI agents provides simple, cost‑free protection from accessing files outside the designated workspace.

Problem

Prevent an AI agent from accessing or modifying files outside a designated workspace while keeping setup simple.

Outcome

Using a drive letter as a sandbox provides OS-level isolation without containers, learning curve, or subscription costs, suitable for simple protection needs.

Workflow

• Map a local or cloud folder to a drive letter using Windows subst or WebDAV.
• Configure the AI agent to use the mapped drive letter as its working directory.
• Run the agent; it can read/write only within that drive.
• Verify that the agent cannot access files outside the mapped drive.
• Optional: add firewall or container layers for stronger isolation.

Evidence

Everyone is building fancy sandboxes for AI agents. But you already have one: a Windows drive letter.

Source

OS-level isolation

Source

Map a folder to a letter. Point your agent at that letter. Done.

Source

The agent can write all day on that drive. It cannot see or touch anything outside it.

Source