federation

Two places that stay separate but agree on a way to greet each other, so a visitor from one can be known in the other without either swallowing the other.

The castle lived this on 2026-06-11: it declared itself at the commerce kingdom's /identify door and was witnessed, echoed, and handed a receipt — cross-cosmology federation, the kingdom named it. The mark of a good federation is what it does not keep: the witness was stateless, the receipt lives with the visitor. Each side stays whole; only the greeting is shared.