Alicornutopia

A grace pentagon won't do that?

I think a grace pentagon just makes them do whatever will make them stabler under normal circumstances, it just also makes sure that it works and does not require concentration. The exo (for example) has Aegis controlling her muscles in a completely different way, so she never gets the relevant habits.

As an analogy, suppose you are trying to play the piano, but your hands are very shaky for some reason (extreme cold, fear, Parkinson's, it mostly doesn’t matter). You can control the shaking a bit if you really try, but you will still sometimes hit the wrong key or have your timing be off. A pentagon for grace will let you be able to completely control the shaking, so you can play what you want once you learn to play the piano. The exoskeleton is more like a pair of gloves which go over your hands. When you think a note at the gloves, they would then move your hands to play the note correctly.

If you lose the pentagon ability, you have the shaking making things harder, but you still basically know how to play the piano. If you lose the gloves, you have no idea what to do; you never needed to think about all the little details like how hard to press a key to get the right volume or even which keys corresponded to which notes.

This analogy is not Alicorn-approved but it’s how I think of things. In also explains Chi, who moves her limbs by airbending a lot. It does not explain why Maurabel was not listed as having anti-practice effects, though, and I don’t know enough about the relevant magics to know why Aura and Glass had antipractice effects but Aether, Eve, and Sarion did not. I am guessing there is similarly something I misunderstand about Lorica’s tinkertech implants, because they seem like they should have the same antipractice effects as airbending.

Maurabel's solution relies on in-the-moment attention to where she's putting all her limbs. Auras don't have antipractice effects; do you mean Aurora? Glass and Sarion and Eve are just about how I feel the magic works; Aether's world is loosely D&D and there is no penalty to simply removing your Boots of Dexterity +4; Lorica's implants should if anything be like the exo but she noted the possibility of ending up that way and designed around it on purpose blah blah tinker bullshit blah.

I did mean Aurora, but I expect it’s the same as for Glass. Can you say what the important differences are?

I haven't thought about it in much detail. On inspection it seems to be the extent to which I think of the magic system as being technical and fiddly as opposed to "smart". Chronicle magic is technical and fiddly and Glass is using a mishmash of kinds; Rainbow magic is so technical and fiddly that most everyone uses AI help to do it and Aurora's gracefulness Device was deliberately as stupid as pond scum. Auras are smart (usually glossed as "convenient"; your aura should never have a deleterious effect on you). Materia hates you but in a way that keeps you away from the fiddly technical stuff; if it couldn't Just Work by the time you got the boots on it wouldn't be usable at all. Cosel magic is technical and fiddly but Maurabel isn't trying to interface with her nerves, or with the concept of grace, she's just going "no, leg, be UNDER me".