Python Tool Install Fix for PEP 668

What this fixes

Common symptom:

• `error: externally-managed-environment`
• Tool install notes say `pip install ...` but the distro blocks it

Prerequisites

• Python 3 installed
• `pipx` installed OR permission to install it via apt
• A writable HOME directory (for venvs/pipx)

Steps and commands

1. Install pipx (recommended on Kali):

`sudo apt update && sudo apt install -y pipx`

`pipx ensurepath`

1. Install a Python CLI tool cleanly:

`pipx install `

Example:

`pipx install semgrep`

1. If you need a library (not a CLI application), use a venv:

`python3 -m venv .venv`

`source .venv/bin/activate`

`python3 -m pip install -U pip`

`python3 -m pip install `

1. If you must run a repo-based tool:

`git clone `

`cd `

`python3 -m venv .venv && source .venv/bin/activate`

`python3 -m pip install -r requirements.txt`

1. Record the installation method:

• pipx package + version
• venv requirements.txt hash/lock if applicable

Expected outputs

• The tool runs from your PATH (pipx) without breaking system packages
• `pip install` works inside the venv without triggering PEP 668 errors

Common errors and troubleshooting

• pipx installed but command not found
• Run `pipx ensurepath` and start a new shell.
• Confirm `~/.local/bin` is in PATH.

• Still seeing externally-managed-environment inside a venv
• You are not using the venv's python/pip. Run `which python3` and `which pip` to verify.

• Temptation to use `--break-system-packages`
• This can break distro-managed tooling. Prefer pipx/venv.

• pipx inject for plugins/extras
• If a pipx-installed tool needs an optional dependency: `pipx inject `.

References

• https://www.kali.org/blog/python-externally-managed/
• https://www.kali.org/docs/general-use/python3-external-packages/
• https://peps.python.org/pep-0668/
• https://github.com/RedSiege/EyeWitness/issues/636

Example inputs

• Tool: eyewitness / semgrep / custom python CLI
• Install style: pipx (CLI) vs venv (library)