To quote from The Rift: "The Jester was fixated upon something he called a 'deepness' which he could not describe." Also, quoting from the Ken mission, "Your creators blundered once, and in doing so, unleashed the deepness that stalks the cold roads of the cosmos" and (possibly related) "The old burnt the cosmos clean in the wars of their youth. Never again will that price be paid." And of course, we know that BP is keeping with the [V] hint that the Shivans are a symptom of a larger problem.
Based on how it finds anyone talking or even thinking about it via Nagari, it may be something integral to the Nagari process itself. <wild_speculation> So far we know nothing about how the Shivans/Vishnans physically communicate. What if they're dependent on another system for Nagari, something connected to the Great Darkness? </wild_speculation>
I have to play Universal Truth a few dozen more times before I'm at all qualified to speak on its contents, however.
[EDIT] Just played it a couple times and ripped the file open in FRED to read everything at my own pace.
"resumption of panoptic function": The Shivans' role in searching for Nagari activity, and subsequent prevention through annihilation?
"Subversion of noosphere underway": I concur with your assessment. Laporte narrowly avoids death/insanity and doesn't even realise it. Hell, if the Shivans take such direct action here, it could have been much worse than just Laporte. Noosphere usually implies more than one mind. If Laporte or another Nagari sensitive had done that without Ken there to moderate the connection, that could have resulted in exactly what the Shivans seek to prevent.
Small but probably crucial correction: it's pano
ntic function. I believe this is related to the the
ontovore which is also mentioned, using onto- to mean a living being, in which case the ontovore is something that eats or destroys all life, and "panontic function" refers to the function of all life ("function" meaning a computational function, which may be how the Shivans/Vishnans conceptualize life).
Also, the "noosphere" is mentioned later in the conversation witnessed by Laporte and Bei:
"If they have turned on themselves, they are failures. The panontos cannot be theirs. The noosphere can never be theirs."
<wild speculation>This suggests that the panontos and noosphere are things, possibly states of mind or vast mainframes constructed by the Brahman(s) which a mind (not an organic, finite mind- possibly not even the Shivans/Vishnans) could use or inhabit.
Of course, the Shivans in that conversation say that we could never achieve it or wouldn't be able to use it- it seems they believe our civil wars represent a crucial failing we could never overcome.</wild speculation>
(another random tangent: is it Brahmans, or Brahman? On separate occasions, the Shivans and Vishnans seem to switch between referring to it as a species and a single entity. Actually, it could be that the Shivans use one, and the Vishnans the other... I should look up all the references to it/them and see if this is the case)
[EDIT2, possibly less off-topic, omg so many words]
Part of the exposition when Laporte asks about the Great War is this:
"external heuristic injection: mandate node severance fallback. force binary isolation/extinction outcome"
Two important things, the first one I didn't notice until now. Cutting Sol off from the GTVA was not an accident; the Shivans did this intentionally. It seems it was a fallback plan... fallback to what, exactly? Ken admits the Shivans accomplished their mission in the Great War: to kill us, or force us to really unite (xenocultural integration). Would the Terrans and Vasudans have returned to war eventually if the Sol node weren't cut off (or did the Shivans predict that)?
Secondly, and more importantly: "external heuristic injection". Laporte notices this. Something told the Shivans that it would be a good idea to do this- something outside their own protocol. Could it be, or be related to, the Great Darkness?