clearstream
(He, Him)
The DM can decide that any action declaration is a success or failure. That includes NPCs.But as long as I have your attention, let me ask you for the 4th time: who gets to decide whether or not an NPC action declaration (of the sort we have been considering) is an auto success or auto failure?
You might be wondering if a DM ought to declare NPC actions automatic successes. In some cases it would seem to me that they ought not, but that is a separate question from what RAW entails they may do.