Install pyenv, and it should automagically use the python version specified in .python-version
Tooling is listed in dev-requirements.txt
For the pre-commit-config to work, make sure you're using rbenv, and have set rbenv global 3.3.6 or higher ruby version. Rubocop pre-commit doesn't respect rbenv local or .ruby-version files, but does respect rbenv global, for some reason.
(The Ruby Version used by arclight is specified in arclight/.ruby-version)