The initial reporting was “drones”, then it was “leaked” that there were reported missile strikes a day later, then (evidently) reporters sifted the supplied evidence from those two claims/sources to determine it was both. Only 50%, (and no less than 50%, a very precise number) was reported taken out, even though the attack was reported as completely successful. This indicates planning. A nation state clearly considered the possibility that “the Houthis did it” wasn’t likely to be accepted as an explanation by the Saudis, meaning the Iranians not only knew of the attack, they didn’t want to engage in an attack that would put them into an all out war and must have discussed it with the attackers, indicating at least a very close collaboration and planning. That is, if they weren’t the ones who actually did the attack. It’s more likely somewhere in between: planned and weapons supplied by Iran but the Houthis carried it out from sites that would indicate the missiles came from the opposite direction of Iran, for plausible deniability.