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Sandbox

A sandbox is one or more virtual machines delivered to a candidate or learner through their browser. You configure it with sandbox.yaml and implement its behavior with lifecycle scripts.

Topics

  • sandbox.yaml — virtual machines, tools, UI, base images, and all configuration fields
  • Tools — terminal, IDE, browser, and instructions
  • Lifecycle Scripts — what each script does, when it runs, and how to write scoring checks
  • CLI Reference — commands, independent VM terminals, live reload, and Bashp MCP tools

Authoring with CLI v1.25–v1.27

Use sandbox attach (v1.25+) for additional terminals without taking ownership of a VM. Use the read-only Bashp MCP tools (v1.26+) to discover helpers and resolve scripts in their item context.

For multi-VM development, build once, start background watchers, and attach independently with v1.27+. Script, asset, and local-library edits update the running VMs' /sandbox files; lifecycle scripts still run only when explicitly requested. See the library-only reload example.