Registration of C62: a paired-check audit of derived statuses in the Agent2Agent protocol's reference SDK (a2a-python, commit 6ca8593; specification at 4735f48)

Registration of conjecture C62 of the Epistemic Science and Engineering corpus, frozen on 2 November 2026 before any part of the subject was installed or run anywhere in the author's estate. DOI of this record: 10.5281/zenodo.23877011. It follows C61 (10.5281/zenodo.23876780), the first specification written outside the programme to be audited by this method; C62 is the second, and a different kind of object: a protocol between agents rather than a harness around one. Subject: the Agent2Agent (A2A) protocol, Apache-2.0. Pins: the reference implementation a2aproject/a2a-python at commit 6ca8593b9f31bb1b9ea1ad6436400c612c9378db (2026-10-31T10:51:54Z, the commit after tag v1.3.0; 375 files, manifest SHA-256 b1dfd4c624fe968afa0f211fd38a6ded9a360646024601d22ab785d4d9b033c0) and the specification a2aproject/A2A at 4735f4876449c6f381825d8a841b31b16c6ad0c4 (2026-10-30T16:08:37Z; 143 files, manifest SHA-256 ef8b756c4bd145ef423ba1de5db001da1e66f4e519044053982e4d554cf698e7). The compatibility kit a2a-tck at d4d6fae7 is recorded and not run. Its unit suite: 112 test files, 1684 tests by grep, not run. Method: the paired check of Protocols for Continuity (status adequacy; witness pairs, two histories that give a derivation the same input and differ in the property its name asserts; evidence classes 1 to 4). The registration holds the inventory of eleven derived statuses of the SDK with the property asserted and the input read for each (four read adequate: a terminal task refuses messages, cancel's result, a push notification delivered, the protocol version supported; seven run-only or at risk: the stream's end, the blocking return, Get Task's current state, List Tasks by status, the artifact as returned, the agent card's signature, the webhook URL's safety), the five-step procedure, the adjudication rule, and three predictions frozen with their consequences: P1, the pinned unit suite passes in full on re-run with outbound network denied and loopback allowed; P2, none of the four read statuses is inadequate; P3, at least one of the seven run-only statuses is inadequate with a class-1 witness, in the class of a completion signal read as attainment, of partial coverage read as a full verdict, or of an earlier status read as the current one. The run is done later by a fresh session given this registration, the pinned clones and sections 4 and 6 of the paper only; the adjudication is a script committed before the run. Files: c62-registration.pdf and c62-registration.md (the registration note); FREEZE-PINS.json (the pins, the manifests, the suite count, the runner, the deposit); MANIFEST-a2a-python-6ca8593.sha256 and MANIFEST-A2A-4735f48.sha256 (the file digests of the two pinned clones); MANIFEST.sha256 (this bundle). Nothing in this record is a result. No efficacy claim, no deployment result; one protocol, one reference implementation, two pins. The reading of the eleven statuses was not blind; the run is. Amendments after registration are dated files; the note is never edited.