Picking a Claude model is really two decisions — which model and how much effort — and the more interesting question is who should make them: a config file, a skill, a cheap router model, or the most capable model delegating downward.
"Self-maintaining" is a seductive phrase, so let's be honest about it up front. You're not going to walk away for a month and come back to a repo that grew new features on its own. What you can build is a loop where Claude does most of the mechanical work — turning issues into pull requests (PRs) — and a separate Claude pass reviews that work before it ever reaches you. You stay the final gate, but you review a clean, already-critiqued PR instead of a blank diff.