I mean, with reliability there's a spectrum. If the risks that an unreliable outcome brings aren't all that bad, then sometimes it's worth it to chase "my agents made an acceptable PR 70% of the time, can I get it to 90?"

Determinism is a different matter. Scripts and hooks are really the main levers you can pull there, but yeah - a a decent script and a cron job will handle certain things much better (and for a fraction of the cost)