[trissim]

The private birth-marker hook registered abstract classes as decoders, then failed when a saved identity tried to instantiate one. BirthlessIncarnation now gives its existing WIRE_BIRTH declaration to AutoRegisterMeta; ThreadIncarnationRecord reads that library-owned registry. The private hook/map are deleted. No new metaclass, production class or marker roster.

Stacked continuation on #2635 (integration/backend-cli-rosters-main, head 534cb07ccb86af072f660f01290f90ed59c645ee). The original source checkpoint 067532a10492dffd97bd3060766a35d6a30feec2, implementation c921abad3 and their exact-head source review are preserved as ancestors. Normal merge head 8dd402e465234d27d4932e384cf236d4daaa9b17 brings in the coherent current-main/backend/CLI/bus/phase base without rewriting those commits.

The merge was clean, including the shared thread_identity.py file. #2623's backend default and this birth-marker registration change both survive. Relative to the coherent base, this remains exactly two changed files: src/agent_comms/thread_identity.py and tests/test_birthless_declarations.py. The four-head integration #2635 remains unchanged and excludes this slice.

External markers (-2/-1/0) and positive recorded births keep their existing wire/CLI owners. Core's watcher retains its class-owned decoding name. Unknown/nonfinite births still fail through recorded-identity validation. Concrete duplicate declarations now use the library's DuplicateRegistryKeyError instead of the private hook's TypeError; abstract declarations are excluded before registration or duplicate checking.

Final focused confirmation on the coherent base: 18 passed in 3.97s, including actual wire/CLI boundaries, concrete/abstract/duplicate declarations, saved identity/equality, isolated release-store consumers and fresh CLI/UI-model imports. git diff --check passes. The original accepted source checkpoint also had 18 passing checks; its initial failed watcher-name expectation and correction remain in the evidence.

Original NRA source/consumer inventories, the old-source crash reproduction and both check outputs are retained under /home/ts/.cache/agent-scratch/birthless-declaration-family. This continuation changes the base through a normal merge; it introduces no further implementation or audit surface.

The accepted review on original head 067532a10 is source acceptance. This PR does not claim installed acceptance. No installer, live-runtime, producer-freshness or typed_table.py work was added. Critical #2633 and the accepted four-slice delivery remain independent.

[trissim]

Accepted source checkpoint at 067532a. The private hook registered abstract decoder classes before ABC construction completed; BirthlessIncarnation now declares its existing WIRE_BIRTH key once to AutoRegisterMeta, whose actual lifecycle excludes abstract classes before duplicate checks/registration. ThreadIncarnationRecord reads that library-owned registry, and the private hook/map are deleted. I read the complete production/test diff, the original NRA consumer inventory (including ThreadProvenance and inherited ReleasedOwner boundary), the installed metaclass implementation, and the retained base-source crash. The existing -2/-1/0 markers and positive recorded births retain their owners, including CoreWatcher's class-owned decoding name; unknown/nonfinite values still fail at RecordedThreadIncarnation. New-case/declaration controls invoke real declarations without mutating the canonical registry. Owner's actual focused result is 18 passed in 3.95s; I inspected the assertions and output and did not rerun that batch. This is source acceptance for integration, not installation or remaining registry-phase closure. The shared thread_identity.py backend-default change in #2623 is disjoint and must survive integration. Critical route #2633/install does not wait on this side slice.