Installation

hermetic is published on PyPI as hermetic-seal. The Python module and CLI are both named hermetic.

Requirements

• Python 3.9 or newer.
• No runtime dependencies. Everything is implemented against the Python standard library.
• Linux, macOS, and Windows are supported. A handful of guard surfaces are POSIX-only (e.g. os.fork); they are skipped silently on Windows.

Install with pip

pip install hermetic-seal

Install with uv

uv add hermetic-seal             # add to a project
uv tool install hermetic-seal    # global, isolated install

Install with pipx

pipx install hermetic-seal

pipx puts hermetic in its own virtualenv. This is fine — hermetic will detect when the target you ask it to run lives in a different interpreter (a different pipx venv, for example) and will switch into Bootstrap Mode to wrap it correctly.

Verify the install

hermetic --version
hermetic --help

A bare hermetic (with no -- and no target) prints help and exits 0.

Adding to a project as a dev dependency

For unit-test use, you usually want hermetic only at test time:

# pyproject.toml
[dependency-groups]
dev = [
    "hermetic-seal",
    # ...
]

Or in a requirements-dev.txt:

hermetic-seal

Uninstall

pip uninstall hermetic-seal

There is no machine state left behind — guards are installed at process start and torn down at process exit.