What your fleet is, beside what it says it is
Everybody has a document describing their machines, and it is wrong. It rots silently because nothing ever compares it against the machines themselves. LibWorld is already watching runners, labels, toolchains, and attached devices in order to schedule builds — which makes it the one thing positioned to notice, without anybody adding a new agent.
The diff is the feature
Git stays the authority and the app cannot edit it: the declared record is derived by cloning each machine's repo, and it is a cache rather than a second source of truth. Seeing a divergence produces a commit, not a form submission.
A screen that merely re-rendered the declared record would add a second place to read the same stale claim. What is worth showing is where declared and observed disagree.
Labels are promises, and probes check them
A label is not a description of what is installed — it is what a host will ACCEPT work for, which is why a true-but-unwanted label is dangerous: it quietly admits builds. Toolchain probes check the promise, and each probe is compared under the label that DECLARED it, because grouping by host instead reports drift on machines that never made the claim.
Labels resolve three ways: verified, hint (declared unassertable, with the reason), and unverified — nobody has ruled either way. Three states rather than two, because an alarm that fires on every macOS host promising a Mac is an alarm nobody reads.
There is a fourth answer to an unverified label and it is often the best one: retire it. One label here promised 31 GB of memory, could not be asked about, and no target had ever required it.
Devices
Attached handsets are reported in three states, not two: attached, unplugged (declared, nothing reporting), and undeclared (reported, nobody declared it). A device row is only as durable as its USB cable, so without a declaration an unplugged phone and one nobody ever owned are the same empty set.