I'll seemingly repeat some of what some people said, to put down
my vision of this issue...
Materials: clay (perhaps a number of units) and some paper or parchment or something (from wood or pre-tanned skin, but we can take advantage of the book-making skills that will develop.
Person: Someone with a high belief in their own god. I don't know of any extant skills, normally available that would apply, but "mystic" or "priest"-class skills would be eminently useful in addition.
Workshop: Kiln, for body, and whatever you'd use for the paper and getting some 'holy mark' marked upon the paper. If there's a "spiritual adviser" noble place going for an actual priest-type person then their table and chair in their office would probably suffice, or borrow the Bookmaker's one.
Capability: Well, I think the individual who is otherwise capable of the task needs to learn that it's possible. Discovered from a book, perhaps or maybe (in future Fortress development) taken a sabbatical at an off-site location where the knowledge needed might have been learnt.
The process: Construct the body. Can be a "clay statue" job that
anybody can create for mundane purposes, but must be made by the actual individual who will imbue it with its particular brand of anima, and probably of a certain minimum quality level. Likewise the slip of paper/etc which
is the 'chem' needs to be skilfully produced, so I foresee plenty of time writing more mundane things (perhaps sermons on the evil of Playing God?
) as a background, as well as contributing to the pottery industry. Build the 'statue' as a building and then (with the chem equipped), interact with the statue-building-thing in some suitable way. (I'm now getting visions of "The Sims"-like jobs of clicking on the statue and having "Admire" and "Imbue with life" options, amongst any others.
) One golem.
And, I think, it should
be one golem. Something about the chem-writing takes a lot out of our golem-maker, perhaps. Maybe suppresses the chem-writing skills (can be a modified skill-check, with a side-counter making it a degraded skill each and every time) so that it's double the effort to make the next, and the next and the next, meaning failure.
Failure modes: Well, I was thinking as how the mood of the creator should be correct. Not too ecstatic, not too unhappy. This
could just mean failure of animation. OTOH, if the creator's chem-writing was done while in an overly cheery mood, might the golem be more procrastinative? If written while in a bad mood could it perhaps give chances for a more impulsive creation (and impulsiveness is
never good in a golem, I imagine).
How to use the golem: Initially, I can see it as being a "pet" (in all but name, but the code could be shared) of its creator, following him around. But reassignable. The creator can give the golem to another individual, and the other individual can give the golem back to its creator (or the creator can reclaim it, maybe). Whoever it is 'pet' to, it follows and (initially) tries to assist in the task of the current 'owner'. Crafts get made quicker, etc. If assigned to a miner/axe-dwarf/soldier, the golem needs to be equipped with a pick/axe/weapons to be effective and help out (although perhaps in the military it might be Ok on its own, with great big fists made of hard stuff, but see below), and should other crafts start to require tools then those also might need duplication, although workshop work might well do without that restriction (an extra pair of hands at the same bench, to speed things up, rather than a second worker at a parallel bench).
Maybe there's a skill-improvement (reset upon reassigning between owners?) which means that a 'raw' golem would actually aid you little (maybe slow you down) in a given job, but eventually it actually becomes quite proficient.
Maybe the pet-type interaction should allow a worker to
leave a golem at a post to continue the job (once beyond, say, "Proficient" in the task it currently has skills in), but beware problems with slovenly or... 'distracted' golems, as affected by core quality and the mood of the creator (if applicable). The former could slow or cease the intended work, the latter might claim more and more resources (even forbidden ones?) and keep on creating whatever object it had originally been tasked to create. Or you might lose the ability to remove "Mister Pump" from pumping, or "Mister Digger" from digging (even through undesignated ground-tiles). Maybe beyond the wit of the creator, even, to reclaim the golem and remove it from the job it was doing. (Or the threat is that the death of the creator means there is no-one left who can control it, if there is no non-creator owner on the scene either. But even if there is he cannot actually reassign the golem to any other person!)
Durability: No fatigue, but perhaps wear might exist. Can only be repaired by the creator, if so. Damage, however... It's a pottery construct (or whatever material, but I'm keeping on with the idea as already written) and smashable. At least an arm can be broken off in combat/adverse conditions. Would probably survive submersion in magma or water. Perhaps would absorb heat from the magma so that contact with water shortly afterwards causes damage (somewhere between mild cracking all the way to destructive splintering). Perhaps acts like a hot creature anyway, so that contact with flammable materials (perhaps as part of its current job) is problematic.
Well, I'm waffling on, so I'll leave it there, but I've other thoughts on the issue. Especially on how they might go rogue. And that it
might be possible to get a golem trained in making golems (after aiding the creator with both writing tasks and pottery ones) and do so more effectively than the original creator might, but more risk of undue independence arising, meaning Golem Fortress might well be nigh for your embark site.