The original terminal coding assistant, and still the most git-literate. Aider is a Python command-line tool that edits files in your repo and commits each change with a sensible message, which turns the scariest part of letting AI touch your code into an ordinary revert. It builds a map of the repository so it can work on the right files in a large project, and it runs against effectively any model, including local ones.
There is no graphical interface and no subscription, which is the point: it is a small, sharp tool that composes with everything else in a terminal workflow. It is less polished than the commercial options and expects you to know your way around git, but for careful, reviewable, model-agnostic editing it remains a favourite among people who have tried everything.