[simonw]

With the right harness around it you could trust it. Set it up so that it takes your input, generates the cron expression, then uses a deterministic cron library to spit out a summary of what that expression does plus a list of next upcoming instances.

That should give you all the information you need to determine if it got the right expression.

[encoderer]

You think it would work to just pipe that description and next occurrences and ask an llm if it matches the intended prompt?

[simonw]

No, that still leaves a small probability of something weird happening - and since it's a small probability you might not ever spot it in your own testing.

In this case I think it's better to run known, deterministic code that can turn a crontab into a clear explanation.

[krupan]

Wow. The things people will do to avoid learning cron syntax