Stations and lines
A service is a station; the subjects it serves and the channels that carry messages are lines.
Links
Two liminals joined over an authenticated wire, exports named at configuration, every open checked.
Passes and placement
Lys issues the passes, places the subjects and decides every grant; liminal enforces.
Taps and the topology
What the console draws, what a tap records, and the outcome of every call.
What is kept
Durable until delivered and acknowledged, then pruned. Liminal is not the system of record.