DefinedTerm · integration
Same-domain rule
The gateway-layer rule that every endpoint a machine door names must be the document’s own domain or a subdomain of it — never a parent, a sibling or a stranger — implemented as one shared module and refusing to guess at registrable-domain suffixes. It matters because it stops one organisation pointing agents at another’s endpoints, and because a single shared implementation is how three interoperating specs avoid each defining "same domain" slightly differently.
Common causes
A rule that slices the last two labels of a hostname reads two unrelated country-code domains as one publisher; the refusal-to-guess rule avoids that by refusing parents and siblings outright.
Nearby terms
This is the build-lens entry, deliberately narrower than the market framing of the same subject: see The same-domain rule — FlashyOS.
Term set: the build vocabulary. Capital-markets terms are defined on gda.group; agent-economy terms on flashygroup.com. One term, one home.