You might be wondering what sort of personality the snaketail has, and the answer is quite simple: she's simply another copy of this furry cyborg's main mind. Specifically, she's a copy that they've decided will refrain from getting any software updates or other edits to her mindstate; and she's a copy who has full authority to examine their main body's mind, and if she doesn't like how that mind has changed, to roll back any alterations to an earlier backup. For example, of course it would be handy to make a few mental tweaks to improve her mathematical ability; but if those tweaks lead down a path to further changes, and to knock-on effects which lead her to abandon her previous values - to stop caring about friends and family in favour of doing nothing but working on abstract proofs - then those mental changes will have done more harm than good. So it's a good idea to plan ahead against any such value drift, long before it becomes a serious problem.
On the other paw, further /physical/ changes are much less fraught... though they still need a good amount of planning, forethought, and consideration of alternatives.