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Sorry if this has already been answered - I just couldn't find it in the docs - perhaps I've just had a really long day and can't think of the right search terms.
*What's the best practice for forcing a failure if a task or flow doesn't pass a custom validation I've made?* 
_For example, if the rows loaded into a destination don't match the row count that was supposed to be loaded? Stuff like that happens with Salesforce all the time and their callbacks aren't very flexible, so I like to check to see if rows loaded are what I expected._

Should I call raise and use the signals functionality?

Hi <@U02A2708XGX>, if this were me I’d check the condition and raise a state like you suggest.
```@task
def task_with_check(...):
    if n_rows != 1000:
        raise FAILED("msg")
    return data```

If you need the signals docs. They are <https://docs.prefect.io/core/concepts/execution.html#state-signals|here>

Note that raising FAILED respects retries. If you don’t want retries, use ENDRUN

Ok, so I wasn't completely off course. Thanks Kevin!