Thanks for the pointer! For what it's worth, I didn't find implementing the tab completion difficult at all for the repo tool, but that of course doesn't mean we shouldn't consider alternatives.

I just stumbled over https://argcomplete.readthedocs.io, which we could use at least for the Python options.

It would be nice to have tab completion for the planner. This can be considered
separately for the driver script and the search component.

I have some experience with implementing tab completion for our repo tool, so if
someone is interested in handling this but would like some advice, I'm happy to
provide it.