Running Claude Code means handing an AI agent the keys to your terminal - it can read files, run commands, modify your codebase, and install packages. Developer Kaveh has published a walkthrough showing how to run Claude Code inside a sandbox so it cannot touch anything outside a designated environment.
The setup uses containerization - think of it as a walled-off virtual computer running inside your actual computer - to isolate Claude Code from the rest of your system. Inside the sandbox, Claude Code operates normally: writing code, running tests, reading project files. Outside it, your personal files, credentials stored elsewhere, and other projects stay untouched. If Claude does something unexpected or destructive, the damage is contained to the sandbox.
Claude Code is an agentic tool, meaning it doesn't just suggest code - it executes it. Most developers run it directly on their machines without restricting what the model can theoretically access. In practice, Claude Code behaves appropriately, but "appropriate by default" and "structurally prevented from causing damage" are different things. The sandbox approach achieves the latter.
The tradeoff is setup complexity. Getting a proper sandbox working requires some familiarity with containerization tools and correct mounting of your project directory into the isolated environment. Developers handling sensitive codebases - client work, production systems, anything with credentials in the project directory - will find the configuration time justified.