How do you avoid the trap of building automation that requires constant manual supervision?

Our team was losing hours every week on repetitive tasks so automating the whole flow felt like an easy win.

The initial run was fast and clean, but edge cases quickly threw everything off.

We ended up spending just as much time auditing the automated results as we used to spend doing the work manually.

Shifting the bottleneck to quality checking wasn't the efficiency boost we planned for.

What rules or checks do you follow to separate tasks that need human eyes from ones you can fully automate?