python.md

Python

Python is managed entirely with uv — for Python version installation, virtual environments, and dependency management.

Installing Python versions

uv python install 3.13        # install latest 3.13
uv python install 3.12.4      # install a specific version
uv python list                # list installed and available versions

Virtual environments

Use mkvenv to create a virtual environment in the current directory:

mkvenv          # create .venv using the latest installed Python
mkvenv 3.12     # create .venv using Python 3.12

This creates .venv/ in the current directory. Activate it with:

source .venv/bin/activate.fish

Projects

For projects with a pyproject.toml, uv manages dependencies directly:

uv init                    # create a new project
uv add requests            # add a dependency
uv sync                    # install all dependencies
uv run python script.py    # run in the project environment

Upgrading dependencies

uvu    # uv lock --upgrade && uv sync

This upgrades all dependencies to the latest allowed versions (within constraints in pyproject.toml) and syncs the environment.

Listing outdated packages

plo    # uv pip list --outdated

mise integration

Mise can also manage Python versions as an alternative to uv python. The two coexist — uv is preferred for project work.

Shell completions

uv shell completions are generated automatically in config.fish:

uv generate-shell-completion fish | source