Chief Engineer

Convoke on creatures was nothing new; bolting it onto every artifact you cast was the wrinkle. This 1/3 turns a board of bodies into the ramp engine for whatever artifacts your deck wants to deploy, and the granted convoke applies to the whole spell, not a discount on a single drop. Tap a few attackers that swung with vigilance, tap mana dorks that have nothing better to do, and a heavy artifact suddenly costs a fraction of its printed mana. The effect rewards a deck that floods the board with cheap creatures and then wants to slam expensive artifacts ahead of curve: the more bodies, the bigger the spell you can sneak out a turn or three early. The constraint that keeps it from being a pure free-cast machine is that it only ever helps artifact spells, and only while you have creatures to tap, so it is dead in a deck without an artifact payload and dead again once the board is empty. The toughness, not the power, is the relevant number: a 1/3 survives the incidental pings and trades that a deck of mana creatures usually dreads, so it tends to stick around long enough to keep enabling the next big drop. It reads like a build-around because it is one: the card asks you to commit to artifacts as a finisher and to creatures as fuel, then pays off the synergy in tempo nobody else gets.