Modal Sandbox

Quick Start

1. Verify prerequisites before doing any work.

modal --version
python -c "import modal,sys; print(modal.__version__); print(sys.executable)"

• Do not assume the default python or python3 interpreter can import modal just because the modal CLI exists.
• Use the interpreter from the active Modal environment, project venv, or the environment behind the installed CLI.
• Do not look for a modal sandbox subcommand. Use modal shell <sandbox_id> for direct access and modal container ... only for generic container inspection.
• Wrap sandbox creation in with modal.enable_output(): when you want local image-build and provisioning logs.
• Set verbose=True on Sandbox.create(...) when you want sandbox operation logs to show up in Modal logs and local output.

2. Create an App before creating a sandbox from outside Modal.