At the same time, since even human design, in its strict sense, is not mechanical (we never include the “nechanism of thought” in considering human design), the ID proposition is also strictly speaking orthogonal to mechanism.
That’s why, given an assumption of design in the living species we see, ie that they originated as a plan in the mind of God, say, then the instantiation of design could have occurred by any number of mechanisms. As Asa Gray said when discussion the mechanism even of Darwinian evolution, “It leaves the design question entirely as it was before”.
That’s analogous to the human situation, too: I compose a tune (non-mechanically, in my mind), and I can hum it, play it on a tuba, write it in manuscript so some other tuba player can play it, code it for a synthesizer etc.
In biology, only one set of mechanisms was involved - ie science can help show how God put the design into life. But the design itself remains outside that, unless one conceives of a God designing by trial and error using prototypoes. Evolution, of course, can be interpreted in such a way, but it’s not inevitable; and as Gray showed, if the darwinian mechanism covered the facts, then it would leave the design question open.
Of course, we now know it doesn’t cover the facts, because of the predominance of neutral evolution and all the rest - making “mechanism” even less tractable.