The worker published and NRC answered 400 on every message:
{"hoofdObject":["Voer een geldige URL in."],"resourceUrl":["Voer een geldige URL in."]}
NRC types both as DRF `URLField`, and Django's URLValidator refuses a single-label host.
Objecten fills them from the object `url` DRF built with `request.build_absolute_uri` —
the Host the *caller* used — so `SITE_DOMAIN` never entered into it. Dropped that env pair;
it was a wrong guess at the mechanism.
The fix is on the caller side: keep the `objecten.local` network alias and point every
writer whose writes must be notified at it — the ACL, the gateway integration tests, and
this slice's verify driver. Readers keep the plain service name.
ADR-0029 updated with the real mechanism and the ceiling it leaves: a new writer using
`objecten:8000` gets a 201 and silently no notification.
Registers an abonnement on the `objecten` kanaal pointing at the existing
webhook sink, writes a RegisterRecord exactly as the ACL does on approval, and
waits for the delivery. That is the whole publish chain in one assertion:
Objecten → its celery worker → NRC → nrc-beat → the callback.
Fails today at the first hop, which is the point:
NRC POST /api/v1/abonnement → 400: {"name":"naam","code":"kanaal_naam",
"reason":"Kanaal met deze naam bestaat niet."}
Also splits S-19b (#150) into #152/#153 in BACKLOG.md — the notification wiring
and the projection re-source are independently deployable (CLAUDE.md §13).