kuilt-gossip

Spreads shared data across a group by having each device keep in touch with only a handful of others, instead of everyone talking to everyone. In a small group that makes no difference; in a large one it's the difference between practical and not — the work each device does grows with the size of its handful, not with the size of the whole group.

Each device picks a few neighbours to exchange updates with, and keeps a short standby list so it can replace a neighbour that drops out. A background safety net (the anti-entropy reconcile in kuilt-quilter) guarantees everyone still ends up agreeing even if a neighbour link is briefly missing — so the network of neighbours only has to be usually connected, not perfectly so.

Under the hood this is a roster-derived k-regular partial view: each peer draws a seeded random k-out sample of the room roster (k ≈ ln N, so the union of everyone's choices is connected with high probability), heals it on membership change with per-peer jitter, and promotes a spare when a neighbour fails. Who fills the view is a pluggable TopologyPolicy: the default RandomKRegular partial mesh, or FullFanout when one hub should re-flood every broadcast to all spokes (the hosted star). It wraps the result as a GossipSeam : Seam exposing two views — the active neighbours (deltas + GC) and full membership (anti-entropy sampling). See docs/gossip-mesh-design.md.