test(acceptance): beoordeling scenario asserts the workflow task is completed (refs #13)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -2,19 +2,130 @@
 
 All notable changes to this project. Generated from Conventional Commits by git-cliff.
 
-## Unreleased
+## v2026.07.0 — 2026-07-14
+
+### Architecture
+- ADR-0005 adopt Stryker.NET for mutation testing (refs #47)
+- ADR-0006 — provision the ACL integration test against the compose stack (refs #46)
+- ADR-0007 + runbooks for the OZ→NRC notification wiring (refs #56)
+- ADR-0009 external-task job-worker pattern (refs #6, #60)
+- ADR-0010 BFF OIDC validation + downstream boundaries (refs #8, #63)
+
+### Bug Fixes
+- Pin OpenZaak/NRC image tags; add smoke log capture on failure (refs #30)
+- Harden oz-db healthcheck and raise compose-up timeout (refs #30)
+- Bake config into images so compose-smoke passes on CI (refs #30)
+- Nrc-init runs migrations only, not setup_configuration (refs #30)
+- Smoke waits on durable services, not the whole project (refs #30)
+- Portable health poll instead of compose --wait (refs #30)
+- Pin upload-artifact to @v3 — @v4 refuses to run on Gitea (refs #47)
+- Buffer the zaak POST body so OpenZaak accepts it (refs #46)
+- Keep dotnet format green under the shared .editorconfig (refs #65)
+- Re-export the full Utrecht package from libs/ui (refs #67)
+- Run checkAuth() at startup to end the login redirect loop (refs #67)
+- Health-check nginx over IPv4 (127.0.0.1) (refs #68)
+- Treat the http portal origin as secure so DigiD PKCE login works (refs #68)
+- Attach the DigiD token to relative BFF calls (refs #68)
+
+### Build
+- Pin Stryker.NET as a local dotnet tool (refs #47)
 
 ### CI
 - Gitea Actions pipeline + runner runbook (refs #30) (#37)
+- ACL Dockerfile + full compose stack for smoke test (refs #30)
+- Switch runner label to ubuntu-latest (refs #30)
+- Run the mutation ratchet as a parallel CI job (refs #47)
+- Publish the Stryker HTML report as a CI artifact (refs #47)
+- Run the ACL integration test as a Gitea Actions job (refs #46)
+- Keep the integration lane local-only; document the runner gap (refs #46)
+- Run the ACL integration test in CI inside the compose network (closes #55) (refs #46)
+- Run the Event Subscriber + projection-api in compose and verify end-to-end (refs #7)
+- Containerize, wire into compose, and verify end-to-end (refs #6)
+- Make Stryker report upload best-effort (refs #62)
+- Retrigger after runner cleanup (refs #6)
+- Retrigger CI (refs #6)
+- Retrigger CI after gitea restart (refs #6)
+- Compose wiring, verify-bff live check, mutation baseline (refs #8)
+- Nx frontend lane (lint/test/build) (refs #65)
+- Serve the self-service app in compose (refs #68)
+- Run Vitest ahead of the production build to stop worker-start timeout (refs #68)
+- Cache the NuGet package store across the .NET jobs (refs #73)
+- Run Playwright from the prebuilt image instead of downloading browsers (refs #73)
 
 ### Chores
 - Add idempotent Gitea backlog seeder
 - Remove bootstrap scripts from main (#35)
+- Contributor workflow — templates, git-cliff, gitea-workflow doc (closes #31) (#38)
 
 ### Documentation
 - Split S-00 into sub-slices (refs #1) (#33)
+- MkDocs scaffold + ADR-0001 + README quickstart (closes #32) (#39)
+- Tighten gitea-actions-gotchas, add local compose (refs #30)
+- ADR-0008 read projection store + demo note for the event path (refs #7)
+- Demo note for submitting a registration (S-05) (refs #6)
+- Demo note for the BFF front door (S-07) (refs #8)
+- Split S-08 into S-08a-d (refs #65)
+- Frontend-decisions + demo note for S-08a (refs #65)
+- Record the orval generator choice (refs #66)
+- Record NL DS + DigiD decisions and demo note (refs #67)
+- Serving/e2e decisions + walking-skeleton demo note (refs #68)
 
 ### Features
 - Placeholder BFF + /health endpoint (closes #28) (#34)
 - Containerize BFF + compose-up smoke (closes #29) (#36)
+- OpenZaak + Postgres + Redis up in compose (refs #10) (#40)
+- Seed BIG catalogus + JWT client for OpenZaak (refs #2) (#41)
+- Open Notificaties up + shared network (closes #2) (#42)
+- Keycloak with four mock realms (closes #3) (#43)
+- Flowable + registratie.bpmn external task (closes #4) (#44)
+- ACL skeleton — OpenZaak default-fill (refs #5) (#45)
+- Add bind-mount local compose for no-make/Windows dev (refs #30)
+- Publish the BIG zaaktype on demand via OZ_PUBLISH (refs #46)
+- Wire OpenZaak → Open Notificaties notifications (refs #56)
+- Project zaak-created notifications into the read projection (refs #7)
+- Persist the read projection and expose webhook + read APIs (refs #7)
+- Enforce the callback bearer before reading the body (refs #7)
+- Implement the Registration aggregate invariants (refs #6)
+- Implement SubmitRegistration and OpenZaakWorker (refs #6)
+- Implement the Flowable Workflow Client and ACL client (refs #6)
+- Expose POST /registrations and the read endpoint (refs #6)
+- Implement self-service submit and openbaar lookup (refs #8)
+- Committed OpenAPI contract + drift guard (refs #8)
+- Self-service portal placeholder page (refs #65)
+- Expose the generated BFF client + repeatable generate target (refs #66)
+- Implement the DigiD registration submit page (refs #67)
+- Runtime config + nginx serve/proxy image (refs #68)
+- Surface submit failures with a retryable alert (refs #68)
+- One citizen reference across self-service and the openbaar register (#79)
+
+### Other
+- Openbaar Register portal — public lookup (#76)
+- Approval flow — temp admin endpoint + status transition to projection (#77)
+
+### Refactor
+- Bake config via dockerfile_inline, drop Dockerfile files (refs #30)
+- Use upstream images verbatim, seed config via docker cp (refs #30)
+- One verify-stack stage for all live-stack checks (closes #58) (refs #46 #56)
+
+### Tests
+- BDD acceptance scenario for opening a zaak (closes #5) (#49)
+- Kill surviving mutants — assert CRS headers, guards, error paths, JWT claims (refs #47)
+- Add Stryker config + mutation make target recording the 95% baseline (refs #47)
+- Integration test opens a real zaak against OpenZaak (refs #46)
+- Verify-notifications smoke + CI job for the OZ→NRC path (refs #56)
+- Project zaak-created notifications into the read projection (refs #7)
+- Ratchet projector mutation baseline to 100% (refs #7)
+- Registration aggregate invariants (refs #6)
+- SubmitRegistration + OpenZaakWorker use cases (refs #6)
+- Workflow Client, ACL client, store and job processor (refs #6)
+- Acceptance scenario for submitting a registration (refs #6)
+- Mutation baseline 90 (achieved 97.7%) + CI/Makefile wiring (refs #6)
+- Endpoints, JWT auth and public-safe projection (refs #8)
+- Acceptance scenario for BFF access (valid/invalid tokens) (refs #8)
+- Self-service portal placeholder renders (refs #65)
+- Generated BFF client is exposed and calls the endpoints (refs #66)
+- DigiD-guarded registration submit page (refs #67)
+- Walking-skeleton Playwright happy path + verify-e2e lane (refs #68)
+- Submit surfaces BFF failures instead of swallowing them (refs #68)
+- Guard that the DigiD token attaches to relative BFF calls (refs #68)
 

apps/openbaar/src/app/register/register-page.html

@@ -43,7 +43,7 @@
         <tbody>
           @for (entry of entries(); track entry.id) {
             <tr>
-              <td>{{ entry.id }}</td>
+              <td>{{ entry.reference }}</td>
               <td>{{ entry.status }}</td>
             </tr>
           }

apps/openbaar/src/app/register/register-page.spec.ts

@@ -5,8 +5,8 @@ import { axe } from 'vitest-axe';
 import { RegisterPage } from './register-page';
 
 const sample: OpenbaarEntry[] = [
-  { id: 'zaak-abc', status: 'INGEDIEND' },
+  { id: 'zaak-abc', status: 'INGEDIEND', reference: 'REG-abc' },
-  { id: 'zaak-def', status: 'INGESCHREVEN' },
+  { id: 'zaak-def', status: 'INGESCHREVEN', reference: 'REG-def' },
 ];
 
 function providers(get = vi.fn().mockReturnValue(of(sample))) {
@@ -22,9 +22,11 @@ describe('RegisterPage', () => {
     await render(RegisterPage, { providers: providers(get).providers });
 
     expect(get).toHaveBeenCalled();
-    expect(await screen.findByText(/zaak-abc/)).toBeTruthy();
+    // The Referentie column shows the citizen's reference (matches the submit confirmation, #78),
+    // not the internal zaak id.
+    expect(await screen.findByText(/REG-abc/)).toBeTruthy();
     expect(screen.getByText(/INGEDIEND/)).toBeTruthy();
-    expect(screen.getByText(/zaak-def/)).toBeTruthy();
+    expect(screen.getByText(/REG-def/)).toBeTruthy();
   });
 
   it('searches by the entered term', async () => {

docs/architecture/adr-0012-citizen-reference-correlation.md

@@ -0,0 +1,104 @@
+# ADR-0012: One citizen-facing reference across self-service and the openbaar register
+
+- **Status:** Accepted
+- **Date:** 2026-07-14
+- **Deciders:** Respellion engineering
+- **Relates to:** #78 (adr-proposal); builds on ADR-0008 (read projection), ADR-0001 (loose coupling), ADR-0009 (external-task worker / zaak creation)
+
+## Context
+
+A citizen submits through the self-service portal and is shown a confirmation with a
+**reference** so they can find their registration back in the public register. But the two
+sides showed **different identifiers**:
+
+- The self-service confirmation shows the **domain `registrationId`** — a GUID minted by the
+  domain aggregate (`RegistrationId.New()`) when the registration is created, before any zaak
+  exists.
+- The openbaar register showed the **zaak id** — the UUID from the NRC `hoofdObject` URL,
+  assigned by OpenZaak when the ACL opens the zaak.
+
+These never match, so the reference on the confirmation was useless for looking the entry up.
+The two identifiers live on opposite sides of the ACL boundary and are generated by different
+systems at different times, so there is no way to reconcile them after the fact without a
+correlating value carried across the boundary.
+
+The NRC notification the Event Subscriber consumes carries only the zaak URL plus the fixed
+`kenmerken` (`bronorganisatie`, `zaaktype`, `vertrouwelijkheidaanduiding`) — **not** the
+`registrationId`, the bsn, or the `identificatie`. ADR-0008 already recorded that filling any
+such field means reading the zaak **through the ACL** (§8.1) and deferred it as a follow-up.
+This is that follow-up, scoped to the one field the citizen actually needs.
+
+## Decision
+
+**Use the domain `registrationId` as the zaak's `identificatie`, and surface that single value
+as the citizen-facing `reference` on both portals. The Event Subscriber enriches the projection
+with the reference by reading the zaak through the ACL, and stores it in the replay log so
+rebuild stays log-only.**
+
+Concretely, following the request path:
+
+1. **Domain → ACL (write).** When the OpenZaak worker opens a zaak, it passes
+   `registration.Id` to the ACL (`IAclClient.OpenZaakAsync(bsn, reference, …)`). The ACL sets
+   it as the zaak's `identificatie` on `POST /zaken`. OpenZaak's `identificatie` is unique per
+   `bronorganisatie` and ≤ 40 chars — a GUID string fits. The ACL remains the only code that
+   constructs ZGW payloads (§8.1); the domain never sees a ZGW URL.
+2. **Event Subscriber → ACL (read).** On a notification, the subscriber asks the ACL for the
+   zaak's reference via a new `POST /zaken/reference` endpoint (`{ zaakUrl } → { reference }`),
+   which reads the zaak's `identificatie` through the ACL's OpenZaak gateway. The subscriber
+   still never talks to ZGW itself (§8.1) — it depends only on the ACL, over HTTP.
+3. **Projection + replay log.** The reference is written both to the `register_projection` row
+   **and** to the `processed_notifications` replay log (a new nullable `reference` column on
+   each). Storing it in the log is what keeps ADR-0008's "**rebuild replays the log, not
+   OpenZaak**" invariant true: `POST /admin/rebuild` reproduces the reference from the log
+   without re-reading the ACL.
+4. **BFF + openbaar.** The public view (`OpenbaarProjection.PublicView`) exposes
+   `id`, `status`, and `reference` (never bsn/naam), and the openbaar search matches on either
+   `id` or `reference`. The openbaar register's "Referentie" column now renders `reference`.
+
+The end-to-end guarantee is asserted in the Playwright walking-skeleton: the reference captured
+from the submit confirmation must appear as a cell in the public register.
+
+### Why HTTP to the ACL, not the ACL as a library
+
+ADR-0008 floated "extend the ACL with a zaak-read operation, consumed as a library." We instead
+call the ACL **over HTTP**, consistent with every other cross-service hop in this system
+(portals→BFF, domain→ACL). Sharing the ACL as a library would couple the subscriber to the
+ACL's infrastructure assembly and its ZGW client configuration, defeating the anti-corruption
+boundary. The HTTP endpoint keeps the ACL the single owner of ZGW access and its config.
+
+## Consequences
+
+**Positive**
+
+- One reference, end to end: the citizen's confirmation value is exactly what the public
+  register shows and searches by.
+- §8.1 stays intact — only the ACL reads or writes ZGW; the subscriber depends on the ACL, not
+  OpenZaak.
+- Rebuild stays log-only (ADR-0008): the reference is replayed from `processed_notifications`,
+  so `/admin/rebuild` needs no ACL/ZGW access.
+- The column additions are nullable and additive; older rows without a reference are tolerated.
+
+**Negative / costs**
+
+- A new coupling: the Event Subscriber now depends on the ACL being reachable
+  (`Acl__BaseUrl`, compose `depends_on: acl`). A registration whose reference read fails will
+  need the notification redelivered (NRC already redelivers; the projection upsert is
+  idempotent).
+- One extra HTTP hop per notification (subscriber→ACL→OpenZaak) on the projection path. Bounded:
+  one small GET per zaak, off the citizen's request path.
+- `identificatie` now carries semantic meaning (it equals the `registrationId`). If OpenZaak
+  were ever configured to auto-generate `identificatie`, the correlation would break; the ACL
+  setting it explicitly is now load-bearing.
+
+## Alternatives considered
+
+- **Carry the `registrationId` in the notification** — rejected: NRC `kenmerken` are fixed and
+  the notification content is not ours to extend; it would also couple the projection to a
+  bespoke notification shape.
+- **Show the zaak id on the confirmation instead** — rejected: the zaak does not exist yet when
+  the confirmation is returned (the worker opens it asynchronously, ADR-0009), so the domain has
+  no zaak id to show at submit time.
+- **Store only on the projection row, re-read the ACL on rebuild** — rejected: it would make
+  rebuild depend on the ACL/ZGW, breaking ADR-0008's log-only rebuild invariant.
+- **Reconcile the two ids in a lookup table** — rejected: adds write-only state and a second
+  source of truth for a value that can simply be the same on both sides.

docs/architecture/adr-0013-behandel-portal-wiring.md

@@ -0,0 +1,76 @@
+# ADR-0013: Behandel-portal wiring — multi-realm BFF auth, werkbak from Flowable tasks, decision completes the task
+
+- **Status:** Accepted
+- **Date:** 2026-07-15
+- **Deciders:** Respellion engineering
+- **Relates to:** #84 (adr-proposal), S-12 (#13); builds on ADR-0010 (BFF OIDC), ADR-0011 (approval status flow), ADR-0009 (external-task worker), ADR-0008 (read projection)
+
+## Context
+
+S-12 adds the behandel-portal: a behandelaar logs in, sees a **werkbak** of registrations awaiting
+beoordeling, and decides each (goedkeuren/afwijzen). Three questions had no obvious answer and shape
+the whole slice.
+
+1. **Which realm authenticates behandelaars, and how does the BFF accept it?** Citizens use the
+   `digid` realm (ADR-0010); staff use a separate `medewerker` realm with roles (`behandelaar`,
+   `teamlead`). Keycloak realms are distinct issuers with distinct signing keys, so the BFF's single
+   `digid`-realm JWT validation rejects a medewerker token outright.
+2. **Where does the werkbak get its data?** The registrations awaiting beoordeling could come from
+   the read projection (status-filtered rows) or from the Flowable `Beoordelen` user tasks (S-12b).
+3. **How does a decision correlate to the workflow?** The process parks at the `Beoordelen` user
+   task; the decision must advance it, and also apply the domain transition (ADR-0011).
+
+## Decision
+
+**The BFF validates a second realm for behandel endpoints; the werkbak is the set of open Flowable
+`Beoordelen` tasks (read through the domain); and a decision both applies the domain transition and
+completes the Flowable task.**
+
+- **Multi-realm BFF auth.** The BFF registers a second JWT bearer scheme (`medewerker`, authority =
+  the medewerker realm) alongside the default `digid` scheme. `/behandel/*` endpoints require an
+  authorization policy bound to the `medewerker` scheme **and** the `behandelaar` role. Keycloak puts
+  realm roles in the nested `realm_access.roles` claim, which ASP.NET does not map automatically, so
+  the scheme's `OnTokenValidated` lifts those roles onto the principal as role claims. Self-service
+  keeps the `digid` scheme. Audience validation stays off (ADR-0010's deferred hardening).
+- **Werkbak = Flowable user tasks (via the domain).** The domain's `Werkbak` query reads the open
+  `Beoordelen` tasks from the Workflow Client (§8.2, `IUserTaskClient`) and enriches each with its
+  aggregate's bsn + status; `GET /behandel/werkbak` exposes it and the BFF proxies it behind the
+  behandelaar policy. The list **is** the authoritative set of claimable/decidable work items, so a
+  decision acts on a real task with no separate correlation store. The read projection stays the
+  anonymous openbaar model — we do **not** project `IN_BEHANDELING` or populate staff-only personal
+  data (both deferred in ADR-0008) just to render a staff view.
+- **Decision completes the task (S-12c-2).** A behandelaar decision applies the domain transition
+  (aggregate + ACL for approval, per ADR-0011) **and** completes the Flowable `Beoordelen` task
+  (looked up by registrationId), so the process advances. Implemented in the next sub-slice; recorded
+  here so the boundary is decided up front.
+
+Delivery is split: **S-12c-1** (this PR) = multi-realm auth + werkbak read; **S-12c-2** = the decide
+endpoint + task completion.
+
+## Consequences
+
+**Positive**
+
+- Staff and citizens are cleanly separated by realm; the `behandelaar` role gates the behandel API.
+- The werkbak reflects exactly what a behandelaar can act on; claim/decide need no extra correlation.
+- No premature projection changes — the openbaar read model stays focused and personal-data-free.
+- Only the ACL/Workflow Client talk to their peers; the BFF still fans out only to domain/projection
+  (§8.3).
+
+**Negative / costs**
+
+- The BFF now depends on two Keycloak realms being reachable (`Keycloak:MedewerkerAuthority`).
+- Rendering the werkbak fans out to Flowable (one task query) plus a store read per task — acceptable
+  for the caseload sizes here; a denormalized staff read model is an additive follow-up if needed.
+- Realm separation (distinct issuers/keys) is validated live, not in the BFF unit tests, where issuer
+  validation is off and one test key signs both realms; the tests exercise the role-based authorization.
+
+## Alternatives considered
+
+- **Werkbak from the read projection** — rejected for now: needs new plumbing to project
+  `IN_BEHANDELING` and to populate staff-only bsn/naam (deferred, ADR-0008), plus a separate way to
+  find the Flowable task at decide-time. Revisit if a high-volume denormalized staff view is needed.
+- **One JWT scheme accepting both realms (issuer validation off)** — rejected: trusting multiple
+  issuers without validation is a security regression; two schemes keep each realm's issuer/key checked.
+- **A dedicated behandel BFF/service** — rejected as premature; one BFF with per-endpoint policies is
+  enough at this size and keeps §8.3 simple.

docs/demo-script.md

@@ -227,3 +227,24 @@ curl -fsS http://localhost:8140/openbaar/register | jq
 > **End of walking skeleton** (S-09 + S-09b): submit → process → projection → public visibility, from
 > INGEDIEND through approval to INGESCHREVEN. The subscriber takes any post-creation status-set as the
 > approval (ADR-0011) — a walking-skeleton assumption that tightens when more transitions arrive (S-12+).
+
+## #78 — One reference across both portals (ADR-0012)
+
+Before this change the self-service confirmation and the openbaar register showed **different**
+identifiers, so a citizen could not look their registration back up. Now both show the same
+**reference**: the domain `registrationId` is set as the zaak's `identificatie` by the ACL, and the
+Event Subscriber enriches the projection with it by reading the zaak through the ACL (§8.1) — storing
+it in the replay log so rebuild stays log-only (ADR-0008).
+
+**The path:** domain passes `registrationId` → ACL sets it as `zaak.identificatie` → NRC →
+Event Subscriber asks the ACL for the reference → projection row + replay log → openbaar register.
+
+```bash
+# Submit as in S-09 and note the reference on the confirmation, then find it in the public register:
+ref="<registration-reference-from-the-confirmation>"
+curl -fsS "http://localhost:8140/openbaar/register?q=$ref" | jq
+# → [ { "id": "<zaak-uuid>", "status": "INGEDIEND", "reference": "<same-ref-as-confirmation>" } ]
+```
+
+> The openbaar register's "Referentie" column and its search now use this reference — the exact value
+> the citizen saw on submit. Asserted end-to-end by the Playwright happy path.

infra/docker-compose.yml

@@ -349,6 +349,8 @@ services:
       # Keycloak (start-dev) derives the issuer from the request host, so the BFF authority and the
       # verify token request both use keycloak:8080 to keep the issuer consistent.
       Keycloak__Authority: http://keycloak:8080/realms/digid
+      # Behandelaars authenticate against the medewerker realm; the BFF validates it for /behandel/* (S-12c).
+      Keycloak__MedewerkerAuthority: http://keycloak:8080/realms/medewerker
       Downstream__Domain__BaseUrl: http://domain:8080/
       Downstream__Projection__BaseUrl: http://projection-api:8080/
     ports:
@@ -396,6 +398,9 @@ services:
     image: register-referentie/event-subscriber:dev
     environment:
       ConnectionStrings__Projection: Host=projection-db;Database=projection;Username=projection;Password=projection
+      # The subscriber enriches the projection with each zaak's reference (identificatie) by asking
+      # the ACL — the only code allowed to read ZGW (§8.1, #78).
+      Acl__BaseUrl: http://acl:8080/
       # The bearer Open Notificaties must present on the abonnement callback. NRC's
       # registration probe expects a 401 without it (ADR-0007). Dev-only token.
       EventSubscriber__Webhook__AuthToken: ${NOTIFICATION_WEBHOOK_TOKEN:-Bearer big-reference-notifications}
@@ -410,6 +415,8 @@ services:
     depends_on:
       projection-db:
         condition: service_healthy
+      acl:
+        condition: service_healthy
     networks: [cg]
 
   # The read side of the projection. Shares Projection.ReadModel, so build context is root.

infra/run-domain-check.sh

@@ -51,18 +51,71 @@ loc="$(docker run --rm --network "$net" curlimages/curl:latest \
 echo ">> registration accepted at $loc"
 
 echo ">> polling the domain until the worker records the opened zaak"
+zaak_ok=""
 for _ in $(seq 1 30); do
   body="$(docker run --rm --network "$net" curlimages/curl:latest \
     -fsS "http://$dom_ip:8080$loc" 2>/dev/null || true)"
   if echo "$body" | grep -q '/zaken/api/v1/zaken/'; then
     echo "OK — the domain opened a zaak and recorded it on the registration:"
     echo "$body" | cut -c1-300
-    exit 0
+    zaak_ok=1
+    break
   fi
   sleep 2
 done
+if [ -z "$zaak_ok" ]; then
   echo "FAIL — the registration never received a zaak URL" >&2
   echo "--- domain log ---" >&2; docker logs "$dom" 2>&1 | tail -15 >&2
   acl="$(docker ps -q --filter 'name=[-_]acl[-_]' | head -1)"
   [ -n "$acl" ] && { echo "--- acl log ---" >&2; docker logs "$acl" 2>&1 | tail -15 >&2; }
   exit 1
+fi
+
+# ── S-12b: the process now parks at the Beoordelen user task. Exercise the exact Flowable REST
+# contract the Workflow Client uses (query/claim/complete) against the live engine, reaching
+# flowable-rest by container IP (same in-network constraint as above). ──────────────────────────
+fl="$(docker ps -q --filter 'name=flowable-rest' | head -1)"
+[ -n "$fl" ] || { echo "ERROR: no running flowable-rest container" >&2; exit 1; }
+fl_base="http://$(ip "$fl"):8080/flowable-rest/service"
+reg_id="${loc##*/}"
+
+# Extracts the Beoordelen task id for our registration from a Flowable task-query response on stdin.
+# Tolerates an empty/non-JSON body (a transient failure during the poll) by printing nothing.
+task_for_reg() { REG_ID="$reg_id" python3 -c "import os,sys,json
+try:
+    d=json.load(sys.stdin)
+except Exception:
+    d={}
+rid=os.environ['REG_ID']
+# Flowable's task-query returns the included process variables under 'variables'.
+print(next((t['id'] for t in (d.get('data') or [])
+    if any(v.get('name')=='registrationId' and v.get('value')==rid for v in (t.get('variables') or []))), ''))"; }
+
+flcurl() { docker run --rm --network "$net" curlimages/curl:latest -fsS -u rest-admin:test "$@"; }
+query='{"processDefinitionKey":"registratie","taskDefinitionKey":"Beoordelen","includeProcessVariables":true}'
+
+echo ">> polling Flowable for the Beoordelen user task (werkbak)"
+task_id=""
+for _ in $(seq 1 30); do
+  resp="$(flcurl -X POST "$fl_base/query/tasks" -H 'Content-Type: application/json' -d "$query" 2>/dev/null || true)"
+  task_id="$(printf '%s' "$resp" | task_for_reg)"
+  [ -n "$task_id" ] && break
+  sleep 2
+done
+[ -n "$task_id" ] || { echo "FAIL — no Beoordelen task appeared for registration $reg_id" >&2; docker logs "$dom" 2>&1 | tail -15 >&2; exit 1; }
+echo ">> Beoordelen task $task_id is waiting"
+
+echo ">> claiming the task as merel-behandelaar"
+flcurl -X POST "$fl_base/runtime/tasks/$task_id" -H 'Content-Type: application/json' \
+  -d '{"action":"claim","assignee":"merel-behandelaar"}' >/dev/null
+
+echo ">> completing the beoordeling (goedkeuren)"
+flcurl -X POST "$fl_base/runtime/tasks/$task_id" -H 'Content-Type: application/json' \
+  -d '{"action":"complete","variables":[{"name":"besluit","type":"string","value":"goedkeuren"}]}' >/dev/null
+
+echo ">> asserting the process finished (no Beoordelen task remains for the registration)"
+resp="$(flcurl -X POST "$fl_base/query/tasks" -H 'Content-Type: application/json' -d "$query")"
+still="$(printf '%s' "$resp" | task_for_reg)"
+[ -z "$still" ] || { echo "FAIL — Beoordelen task $still still active after completion" >&2; exit 1; }
+echo "OK — behandelaar claimed and completed the Beoordelen task; the registratie process finished"
+exit 0

libs/api-client/src/lib/generated/bff-api.ts

@@ -24,9 +24,15 @@ import {
   Observable
 } from 'rxjs';
 
+export interface DecideRequest {
+  besluit: string;
+}
+
 export interface OpenbaarEntry {
   id: string;
   status: string;
+  /** @nullable */
+  reference: string | null;
 }
 
 export interface SubmitAccepted {
@@ -34,6 +40,12 @@ export interface SubmitAccepted {
   status: string;
 }
 
+export interface WerkbakItem {
+  registrationId: string;
+  bsn: string;
+  status: string;
+}
+
 export type GetOpenbaarRegisterParams = {
 q?: string;
 };
@@ -213,4 +225,73 @@ export class BffApiV1Service {
     );
   }
 
+ getBehandelWerkbak<TData = WerkbakItem[]>( options?: HttpClientBodyOptions): Observable<TData>;
+ getBehandelWerkbak<TData = WerkbakItem[]>( options?: HttpClientEventOptions): Observable<HttpEvent<TData>>;
+ getBehandelWerkbak<TData = WerkbakItem[]>( options?: HttpClientResponseOptions): Observable<AngularHttpResponse<TData>>;
+  getBehandelWerkbak<TData = WerkbakItem[]>(
+     options?: HttpClientObserveOptions): Observable<TData | HttpEvent<TData> | AngularHttpResponse<TData>> {
+    if (options?.observe === 'events') {
+      return this.http.get<TData>(
+      `/behandel/werkbak`,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'events',
+      }
+    );
+    }
+
+    if (options?.observe === 'response') {
+      return this.http.get<TData>(
+      `/behandel/werkbak`,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'response',
+      }
+    );
+    }
+
+    return this.http.get<TData>(
+      `/behandel/werkbak`,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'body',
+      }
+    );
+  }
+
+ postBehandelRegistrationsIdDecide<TData = void>(id: string,
+    decideRequest: DecideRequest, options?: HttpClientBodyOptions): Observable<TData>;
+ postBehandelRegistrationsIdDecide<TData = void>(id: string,
+    decideRequest: DecideRequest, options?: HttpClientEventOptions): Observable<HttpEvent<TData>>;
+ postBehandelRegistrationsIdDecide<TData = void>(id: string,
+    decideRequest: DecideRequest, options?: HttpClientResponseOptions): Observable<AngularHttpResponse<TData>>;
+  postBehandelRegistrationsIdDecide<TData = void>(
+    id: string,
+    decideRequest: DecideRequest, options?: HttpClientObserveOptions): Observable<TData | HttpEvent<TData> | AngularHttpResponse<TData>> {
+    if (options?.observe === 'events') {
+      return this.http.post<TData>(
+      `/behandel/registrations/${id}/decide`,
+      decideRequest,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'events',
+      }
+    );
+    }
+
+    if (options?.observe === 'response') {
+      return this.http.post<TData>(
+      `/behandel/registrations/${id}/decide`,
+      decideRequest,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'response',
+      }
+    );
+    }
+
+    return this.http.post<TData>(
+      `/behandel/registrations/${id}/decide`,
+      decideRequest,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'body',
+      }
+    );
+  }
+
 };

services/acl/Acl.Api/Program.cs

@@ -20,7 +20,7 @@ app.MapGet("/health", () => "Healthy");
 // The ACL's single operation, exposed as a service endpoint.
 app.MapPost("/zaken", async (OpenZaakRequest body, AclService acl, CancellationToken ct) =>
 {
-    var zaakUrl = await acl.OpenZaakAsync(new DomainRegistration(body.Bsn), ct);
+    var zaakUrl = await acl.OpenZaakAsync(new DomainRegistration(body.Bsn, body.Reference), ct);
     return Results.Ok(new { zaakUrl = zaakUrl.ToString() });
 });
 
@@ -32,10 +32,20 @@ app.MapPost("/statussen", async (SetStatusRequest body, AclService acl, Cancella
     return Results.NoContent();
 });
 
+// Read a zaak's public-safe reference (its identificatie). The Event Subscriber calls this to enrich
+// the read projection without reading ZGW itself (§8.1, #78).
+app.MapPost("/zaken/reference", async (ZaakReferenceRequest body, AclService acl, CancellationToken ct) =>
+{
+    var reference = await acl.GetZaakReferenceAsync(new Uri(body.ZaakUrl), ct);
+    return Results.Ok(new { reference });
+});
+
 app.Run();
 
-public sealed record OpenZaakRequest(string Bsn);
+public sealed record OpenZaakRequest(string Bsn, string Reference);
 
 public sealed record SetStatusRequest(string ZaakUrl);
 
+public sealed record ZaakReferenceRequest(string ZaakUrl);
+
 public partial class Program;

services/acl/Acl.Application/AclService.cs

@@ -13,7 +13,8 @@ public sealed class AclService(IZaakGateway gateway, AclDefaults defaults, ICloc
             defaults.VerantwoordelijkeOrganisatie,
             defaults.Vertrouwelijkheidaanduiding,
             defaults.ZaaktypeUrl,
-            clock.Today);
+            clock.Today,
+            registration.Reference);
 
         return gateway.OpenZaakAsync(request, ct);
     }
@@ -28,4 +29,12 @@ public sealed class AclService(IZaakGateway gateway, AclDefaults defaults, ICloc
 
         return gateway.SetZaakToEindstatusAsync(zaakUrl, defaults.ZaaktypeUrl, clock.Today, ct);
     }
+
+    /// <summary>The zaak's reference (its ZGW identificatie), for the read projection (#78).</summary>
+    public Task<string> GetZaakReferenceAsync(Uri zaakUrl, CancellationToken ct = default)
+    {
+        ArgumentNullException.ThrowIfNull(zaakUrl);
+
+        return gateway.GetZaakIdentificatieAsync(zaakUrl, ct);
+    }
 }

services/acl/Acl.Application/DomainRegistration.cs

@@ -1,4 +1,5 @@
 namespace Acl.Application;
 
-/// <summary>Domain-language payload handed to the ACL. No ZGW concepts here.</summary>
+/// <summary>Domain-language payload handed to the ACL. No ZGW concepts here. <see cref="Reference"/>
-public sealed record DomainRegistration(string Bsn);
+/// is the registration's own id; the ACL records it as the zaak identificatie (adr-proposal #78).</summary>
+public sealed record DomainRegistration(string Bsn, string Reference);

services/acl/Acl.Application/IZaakGateway.cs

@@ -12,4 +12,8 @@ public interface IZaakGateway
     /// the catalogus and POSTs a status against the zaak, dated <paramref name="datumStatusGezet"/>.
     /// </summary>
     Task SetZaakToEindstatusAsync(Uri zaakUrl, Uri zaaktypeUrl, DateOnly datumStatusGezet, CancellationToken ct = default);
+
+    /// <summary>Read the zaak's <c>identificatie</c> — the public-safe reference the register shows.
+    /// The Event Subscriber calls this through the ACL rather than reading ZGW itself (§8.1, #78).</summary>
+    Task<string> GetZaakIdentificatieAsync(Uri zaakUrl, CancellationToken ct = default);
 }

services/acl/Acl.Application/ZaakRequest.cs

@@ -6,4 +6,5 @@ public sealed record ZaakRequest(
     string VerantwoordelijkeOrganisatie,
     string Vertrouwelijkheidaanduiding,
     Uri Zaaktype,
-    DateOnly Startdatum);
+    DateOnly Startdatum,
+    string Identificatie);

services/acl/Acl.Infrastructure/OpenZaakGateway.cs

@@ -20,7 +20,8 @@ public sealed class OpenZaakGateway(HttpClient http, OpenZaakOptions options) :
                 request.Zaaktype.ToString(),
                 request.VerantwoordelijkeOrganisatie,
                 request.Startdatum.ToString("yyyy-MM-dd"),
-                request.Vertrouwelijkheidaanduiding)),
+                request.Vertrouwelijkheidaanduiding,
+                request.Identificatie)),
         };
         message.Headers.Authorization =
             new AuthenticationHeaderValue("Bearer", ZgwToken.Mint(options.ClientId, options.Secret));
@@ -47,40 +48,69 @@ public sealed class OpenZaakGateway(HttpClient http, OpenZaakOptions options) :
         ArgumentNullException.ThrowIfNull(zaaktypeUrl);
 
         var eindstatus = await ResolveEindstatusAsync(zaaktypeUrl, ct);
+        var resultaattype = await ResolveResultaattypeAsync(zaaktypeUrl, ct);
 
-        using var message = new HttpRequestMessage(
+        // OpenZaak refuses to set a zaak's eindstatus unless the zaak has a resultaat
-            HttpMethod.Post, new Uri(options.BaseUrl, "/zaken/api/v1/statussen"))
+        // ("resultaat-does-not-exist"), so record the resultaat first, then the status.
-        {
+        await PostAsync("/zaken/api/v1/resultaten",
-            Content = JsonContent.Create(new StatusDto(
+            new ResultaatDto(zaakUrl.ToString(), resultaattype.ToString()), "Setting the zaak resultaat", ct);
-                zaakUrl.ToString(),
+
-                eindstatus.ToString(),
+        await PostAsync("/zaken/api/v1/statussen",
             // datumStatusGezet is a ZGW date-time; set it at the start of the given day (UTC).
-                datumStatusGezet.ToDateTime(TimeOnly.MinValue, DateTimeKind.Utc).ToString("yyyy-MM-ddTHH:mm:ssZ"))),
+            new StatusDto(zaakUrl.ToString(), eindstatus.ToString(),
+                datumStatusGezet.ToDateTime(TimeOnly.MinValue, DateTimeKind.Utc).ToString("yyyy-MM-ddTHH:mm:ssZ")),
+            "Setting the zaak status", ct);
+    }
+
+    public async Task<string> GetZaakIdentificatieAsync(Uri zaakUrl, CancellationToken ct = default)
+    {
+        ArgumentNullException.ThrowIfNull(zaakUrl);
+
+        using var message = new HttpRequestMessage(HttpMethod.Get, zaakUrl);
+        message.Headers.Authorization =
+            new AuthenticationHeaderValue("Bearer", ZgwToken.Mint(options.ClientId, options.Secret));
+        // The zaak is a geo resource; the Zaken API requires the CRS header even on GET.
+        message.Headers.Add("Accept-Crs", "EPSG:4326");
+
+        using var response = await http.SendAsync(message, ct);
+        await EnsureSuccessAsync(response, "Reading the zaak", ct);
+
+        var zaak = await response.Content.ReadFromJsonAsync<ZaakReadDto>(ct)
+            ?? throw new InvalidOperationException("OpenZaak returned an empty zaak response");
+        return zaak.Identificatie;
+    }
+
+    // POSTs a non-geo ZGW resource (resultaat/status — no CRS headers). Buffers the body so uwsgi gets
+    // a Content-Length instead of a chunked body (as with zaak-create).
+    private async Task PostAsync(string path, object dto, string action, CancellationToken ct)
+    {
+        using var message = new HttpRequestMessage(HttpMethod.Post, new Uri(options.BaseUrl, path))
+        {
+            Content = JsonContent.Create(dto),
         };
         message.Headers.Authorization =
             new AuthenticationHeaderValue("Bearer", ZgwToken.Mint(options.ClientId, options.Secret));
-        // The status resource carries no geometry, so no CRS headers. As with zaak-create, buffer the
-        // body so uwsgi gets a Content-Length instead of a chunked body.
         await message.Content.LoadIntoBufferAsync(ct);
 
         using var response = await http.SendAsync(message, ct);
-        response.EnsureSuccessStatusCode();
+        await EnsureSuccessAsync(response, action, ct);
+    }
+
+    // EnsureSuccessStatusCode discards the response body; ZGW returns a JSON problem detail on 400 that
+    // is essential for diagnosing a rejected request, so surface it in the exception.
+    private static async Task EnsureSuccessAsync(HttpResponseMessage response, string action, CancellationToken ct)
+    {
+        if (response.IsSuccessStatusCode)
+            return;
+
+        var body = await response.Content.ReadAsStringAsync(ct);
+        throw new HttpRequestException($"{action} failed: {(int)response.StatusCode} {response.ReasonPhrase}. {body}");
     }
 
     /// <summary>Resolve the zaaktype's eindstatus (the terminal statustype) from the catalogus.</summary>
     private async Task<Uri> ResolveEindstatusAsync(Uri zaaktypeUrl, CancellationToken ct)
     {
-        var query = new Uri(options.BaseUrl,
+        var page = await GetCatalogusAsync<StatustypePage>("statustypen", zaaktypeUrl, "statustypen", ct);
-            "/catalogi/api/v1/statustypen?status=alles&zaaktype=" + Uri.EscapeDataString(zaaktypeUrl.ToString()));
-        using var message = new HttpRequestMessage(HttpMethod.Get, query);
-        message.Headers.Authorization =
-            new AuthenticationHeaderValue("Bearer", ZgwToken.Mint(options.ClientId, options.Secret));
-
-        using var response = await http.SendAsync(message, ct);
-        response.EnsureSuccessStatusCode();
-
-        var page = await response.Content.ReadFromJsonAsync<StatustypePage>(ct)
-            ?? throw new InvalidOperationException("OpenZaak returned an empty statustypen response");
         var results = page.Results ?? [];
 
         // OpenZaak flags the terminal statustype (highest volgnummer) as isEindstatus; fall back to the
@@ -91,16 +121,45 @@ public sealed class OpenZaakGateway(HttpClient http, OpenZaakOptions options) :
         return new Uri(eindstatus.Url);
     }
 
+    /// <summary>Resolve the zaaktype's resultaattype from the catalogus (the seed defines one).</summary>
+    private async Task<Uri> ResolveResultaattypeAsync(Uri zaaktypeUrl, CancellationToken ct)
+    {
+        var page = await GetCatalogusAsync<ResultaattypePage>("resultaattypen", zaaktypeUrl, "resultaattypen", ct);
+        var resultaattype = (page.Results ?? []).FirstOrDefault()
+            ?? throw new InvalidOperationException($"No resultaattypen found for zaaktype {zaaktypeUrl}");
+        return new Uri(resultaattype.Url);
+    }
+
+    // GETs a catalogus collection filtered by zaaktype (status=alles includes concept + published).
+    private async Task<T> GetCatalogusAsync<T>(string resource, Uri zaaktypeUrl, string label, CancellationToken ct)
+    {
+        var query = new Uri(options.BaseUrl,
+            $"/catalogi/api/v1/{resource}?status=alles&zaaktype=" + Uri.EscapeDataString(zaaktypeUrl.ToString()));
+        using var message = new HttpRequestMessage(HttpMethod.Get, query);
+        message.Headers.Authorization =
+            new AuthenticationHeaderValue("Bearer", ZgwToken.Mint(options.ClientId, options.Secret));
+
+        using var response = await http.SendAsync(message, ct);
+        await EnsureSuccessAsync(response, $"Querying {label}", ct);
+
+        return await response.Content.ReadFromJsonAsync<T>(ct)
+            ?? throw new InvalidOperationException($"OpenZaak returned an empty {label} response");
+    }
+
     private sealed record ZaakDto(
         [property: JsonPropertyName("bronorganisatie")] string Bronorganisatie,
         [property: JsonPropertyName("zaaktype")] string Zaaktype,
         [property: JsonPropertyName("verantwoordelijkeOrganisatie")] string VerantwoordelijkeOrganisatie,
         [property: JsonPropertyName("startdatum")] string Startdatum,
-        [property: JsonPropertyName("vertrouwelijkheidaanduiding")] string Vertrouwelijkheidaanduiding);
+        [property: JsonPropertyName("vertrouwelijkheidaanduiding")] string Vertrouwelijkheidaanduiding,
+        [property: JsonPropertyName("identificatie")] string Identificatie);
 
     private sealed record ZaakCreatedDto(
         [property: JsonPropertyName("url")] string Url);
 
+    private sealed record ZaakReadDto(
+        [property: JsonPropertyName("identificatie")] string Identificatie);
+
     private sealed record StatusDto(
         [property: JsonPropertyName("zaak")] string Zaak,
         [property: JsonPropertyName("statustype")] string Statustype,
@@ -113,4 +172,14 @@ public sealed class OpenZaakGateway(HttpClient http, OpenZaakOptions options) :
         [property: JsonPropertyName("url")] string Url,
         [property: JsonPropertyName("volgnummer")] int Volgnummer,
         [property: JsonPropertyName("isEindstatus")] bool IsEindstatus);
+
+    private sealed record ResultaatDto(
+        [property: JsonPropertyName("zaak")] string Zaak,
+        [property: JsonPropertyName("resultaattype")] string Resultaattype);
+
+    private sealed record ResultaattypePage(
+        [property: JsonPropertyName("results")] IReadOnlyList<ResultaattypeDto>? Results);
+
+    private sealed record ResultaattypeDto(
+        [property: JsonPropertyName("url")] string Url);
 }

services/acl/Acl.IntegrationTests/OpenZaakGatewayIntegrationTests.cs

@@ -22,12 +22,14 @@ public sealed class OpenZaakGatewayIntegrationTests(OpenZaakFixture stack)
             "seed it with OZ_PUBLISH=1 (`make integration` does this).");
 
         var gateway = new OpenZaakGateway(stack.Http, stack.Options);
+        var reference = Guid.NewGuid().ToString(); // zaak identificatie must be unique per bronorganisatie
         var request = new ZaakRequest(
             Bronorganisatie: "517439943",
             VerantwoordelijkeOrganisatie: "517439943",
             Vertrouwelijkheidaanduiding: "openbaar",
             Zaaktype: zaaktype!,
-            Startdatum: DateOnly.FromDateTime(DateTime.UtcNow));
+            Startdatum: DateOnly.FromDateTime(DateTime.UtcNow),
+            Identificatie: reference);
 
         var zaakUrl = await gateway.OpenZaakAsync(request);
 
@@ -36,11 +38,12 @@ public sealed class OpenZaakGatewayIntegrationTests(OpenZaakFixture stack)
             new Uri(stack.BaseUrl, "/zaken/api/v1/zaken/").ToString(),
             zaakUrl.ToString());
 
-        // ...and that zaak is really persisted with the default-filled fields.
+        // ...and that zaak is really persisted with the default-filled fields + the reference identificatie.
         var zaak = await stack.GetZaakAsync(zaakUrl);
         Assert.Equal(zaaktype.ToString(), zaak.GetProperty("zaaktype").GetString());
         Assert.Equal("517439943", zaak.GetProperty("bronorganisatie").GetString());
         Assert.Equal("openbaar", zaak.GetProperty("vertrouwelijkheidaanduiding").GetString());
+        Assert.Equal(reference, zaak.GetProperty("identificatie").GetString());
     }
 
     [Fact]
@@ -57,7 +60,8 @@ public sealed class OpenZaakGatewayIntegrationTests(OpenZaakFixture stack)
             VerantwoordelijkeOrganisatie: "517439943",
             Vertrouwelijkheidaanduiding: "openbaar",
             Zaaktype: zaaktype!,
-            Startdatum: DateOnly.FromDateTime(DateTime.UtcNow)));
+            Startdatum: DateOnly.FromDateTime(DateTime.UtcNow),
+            Identificatie: Guid.NewGuid().ToString()));
 
         await gateway.SetZaakToEindstatusAsync(zaakUrl, zaaktype!, DateOnly.FromDateTime(DateTime.UtcNow));
 

services/acl/Acl.Tests/AclServiceTests.cs

@@ -22,6 +22,14 @@ public class AclServiceTests
             Approved = (zaakUrl, zaaktypeUrl, datumStatusGezet);
             return Task.CompletedTask;
         }
+
+        public Uri? ReadReferenceFor;
+
+        public Task<string> GetZaakIdentificatieAsync(Uri zaakUrl, CancellationToken ct = default)
+        {
+            ReadReferenceFor = zaakUrl;
+            return Task.FromResult("REG-FROM-ZAAK");
+        }
     }
 
     private static AclDefaults Defaults() => new()
@@ -50,7 +58,7 @@ public class AclServiceTests
         };
         var service = new AclService(gateway, defaults, new FixedClock(new DateOnly(2026, 6, 4)));
 
-        var url = await service.OpenZaakAsync(new DomainRegistration("123456782"));
+        var url = await service.OpenZaakAsync(new DomainRegistration("123456782", "reg-77"));
 
         Assert.Equal(gateway.Result, url);
         var req = Assert.IsType<ZaakRequest>(gateway.Captured);
@@ -59,6 +67,8 @@ public class AclServiceTests
         Assert.Equal("openbaar", req.Vertrouwelijkheidaanduiding);
         Assert.Equal(defaults.ZaaktypeUrl, req.Zaaktype);
         Assert.Equal(new DateOnly(2026, 6, 4), req.Startdatum);
+        // The registration reference becomes the zaak identificatie (#78).
+        Assert.Equal("reg-77", req.Identificatie);
     }
 
     [Fact]
@@ -103,4 +113,27 @@ public class AclServiceTests
         await Assert.ThrowsAsync<ArgumentNullException>(() => service.ApproveZaakAsync(null!));
         Assert.Null(gateway.Approved);
     }
+
+    [Fact]
+    public async Task Reading_a_zaak_reference_returns_the_zaaks_identificatie()
+    {
+        var gateway = new FakeGateway();
+        var service = new AclService(gateway, Defaults(), new FixedClock(new DateOnly(2026, 6, 4)));
+        var zaak = new Uri("http://openzaak/zaken/api/v1/zaken/abc");
+
+        var reference = await service.GetZaakReferenceAsync(zaak);
+
+        Assert.Equal("REG-FROM-ZAAK", reference);
+        Assert.Equal(zaak, gateway.ReadReferenceFor);
+    }
+
+    [Fact]
+    public async Task Reading_a_null_zaak_reference_is_rejected()
+    {
+        var gateway = new FakeGateway();
+        var service = new AclService(gateway, Defaults(), new FixedClock(new DateOnly(2026, 6, 4)));
+
+        await Assert.ThrowsAsync<ArgumentNullException>(() => service.GetZaakReferenceAsync(null!));
+        Assert.Null(gateway.ReadReferenceFor);
+    }
 }

services/acl/Acl.Tests/OpenZaakGatewayTests.cs

@@ -22,7 +22,7 @@ public class OpenZaakGatewayTests
 
     private static ZaakRequest SampleRequest() => new(
         "517439943", "517439943", "openbaar",
-        new("http://openzaak/catalogi/api/v1/zaaktypen/big"), new DateOnly(2026, 6, 4));
+        new("http://openzaak/catalogi/api/v1/zaaktypen/big"), new DateOnly(2026, 6, 4), "REG-REF-1");
 
     private static StubHandler Created(out RequestCapture capture)
     {
@@ -67,6 +67,8 @@ public class OpenZaakGatewayTests
         Assert.Contains("\"vertrouwelijkheidaanduiding\":\"openbaar\"", capture.Body);
         Assert.Contains("\"startdatum\":\"2026-06-04\"", capture.Body);
         Assert.Contains("\"zaaktype\":\"http://openzaak/catalogi/api/v1/zaaktypen/big\"", capture.Body);
+        // The registration reference is set as the zaak identificatie (#78).
+        Assert.Contains("\"identificatie\":\"REG-REF-1\"", capture.Body);
     }
 
     [Fact]
@@ -131,8 +133,9 @@ public class OpenZaakGatewayTests
                 Content = new StringContent("null", Encoding.UTF8, "application/json"),
             }));
 
-        await Assert.ThrowsAsync<InvalidOperationException>(
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(
             () => Gateway(handler).OpenZaakAsync(SampleRequest()));
+        Assert.Contains("empty zaak response", ex.Message);
     }
 
     [Fact]
@@ -144,6 +147,284 @@ public class OpenZaakGatewayTests
             () => Gateway(handler).OpenZaakAsync(null!));
     }
 
+    // --- SetZaakToEindstatusAsync (approval / S-09b) ---
+
+    private const string ZaakUrl = "http://openzaak/zaken/api/v1/zaken/xyz";
+    private static readonly Uri Zaaktype = new("http://openzaak/catalogi/api/v1/zaaktypen/big");
+
+    private sealed class Recorder
+    {
+        public List<HttpRequestMessage> Requests { get; } = [];
+        public List<string?> Bodies { get; } = [];
+        public List<long?> ContentLengths { get; } = [];
+
+        public int IndexOf(string pathContains) =>
+            Requests.FindIndex(r => r.RequestUri!.ToString().Contains(pathContains));
+
+        // The (body, content-length, request) of the single request whose URL contains the segment.
+        public (string? Body, long? Length, HttpRequestMessage Request) Sent(string pathContains)
+        {
+            var i = IndexOf(pathContains);
+            return (Bodies[i], ContentLengths[i], Requests[i]);
+        }
+    }
+
+    // Per-route response config for the four calls the approval makes.
+    private sealed class OzRoutes
+    {
+        public string StatustypenJson { get; init; } = StatustypenPage(withEindstatusFlag: true);
+        public string ResultaattypenJson { get; init; } = """{"results":[{"url":"http://openzaak/catalogi/api/v1/resultaattypen/1"}]}""";
+        public HttpStatusCode StatustypenStatus { get; init; } = HttpStatusCode.OK;
+        public HttpStatusCode ResultaattypenStatus { get; init; } = HttpStatusCode.OK;
+        public HttpStatusCode ResultaatPostStatus { get; init; } = HttpStatusCode.Created;
+        public HttpStatusCode StatusPostStatus { get; init; } = HttpStatusCode.Created;
+    }
+
+    // Routes the approval's four calls by URL: GET /statustypen, GET /resultaattypen (catalogus),
+    // then POST /resultaten and POST /statussen (zaken).
+    private static StubHandler ApprovalStub(Recorder rec, OzRoutes routes) => new(async req =>
+    {
+        rec.Requests.Add(req);
+        // Capture the length BEFORE reading the body (ReadAsStringAsync buffers as a side effect).
+        rec.ContentLengths.Add(req.Content?.Headers.ContentLength);
+        rec.Bodies.Add(req.Content is null ? null : await req.Content.ReadAsStringAsync());
+
+        var url = req.RequestUri!.ToString();
+        if (req.Method == HttpMethod.Get && url.Contains("/statustypen"))
+            return Json(routes.StatustypenStatus, routes.StatustypenJson);
+        if (req.Method == HttpMethod.Get && url.Contains("/resultaattypen"))
+            return Json(routes.ResultaattypenStatus, routes.ResultaattypenJson);
+        if (url.Contains("/resultaten"))
+            return Json(routes.ResultaatPostStatus, """{"url":"http://openzaak/zaken/api/v1/resultaten/new"}""");
+        return Json(routes.StatusPostStatus, """{"url":"http://openzaak/zaken/api/v1/statussen/new"}""");
+    });
+
+    private static HttpResponseMessage Json(HttpStatusCode status, string body) =>
+        new(status) { Content = new StringContent(body, Encoding.UTF8, "application/json") };
+
+    // Two statustypen; the eindstatus is flagged on the *lower* volgnummer so the tests prove the
+    // isEindstatus flag is preferred over "highest volgnummer", not coincidentally equal to it.
+    private static string StatustypenPage(bool withEindstatusFlag) => JsonSerializer.Serialize(new
+    {
+        results = new object[]
+        {
+            new { url = "http://openzaak/catalogi/api/v1/statustypen/1", volgnummer = 1, isEindstatus = withEindstatusFlag },
+            new { url = "http://openzaak/catalogi/api/v1/statustypen/2", volgnummer = 2, isEindstatus = false },
+        },
+    });
+
+    [Fact]
+    public async Task Approving_sets_a_resultaat_then_posts_the_flagged_eindstatus_against_the_zaak()
+    {
+        var rec = new Recorder();
+
+        await Gateway(ApprovalStub(rec, new OzRoutes()))
+            .SetZaakToEindstatusAsync(new Uri(ZaakUrl), Zaaktype, new DateOnly(2026, 6, 4));
+
+        Assert.Equal(4, rec.Requests.Count);
+
+        // Both catalogus queries filter by the zaaktype and carry the bearer.
+        var statustypenGet = rec.Sent("/statustypen").Request;
+        Assert.Equal(HttpMethod.Get, statustypenGet.Method);
+        Assert.Contains(Uri.EscapeDataString(Zaaktype.ToString()), statustypenGet.RequestUri!.ToString());
+        Assert.Equal("Bearer", statustypenGet.Headers.Authorization!.Scheme);
+        Assert.Contains(Uri.EscapeDataString(Zaaktype.ToString()), rec.Sent("/resultaattypen").Request.RequestUri!.ToString());
+
+        // OpenZaak requires a resultaat before the eindstatus, so /resultaten precedes /statussen.
+        Assert.True(rec.IndexOf("/resultaten") < rec.IndexOf("/statussen"));
+
+        var resultaat = rec.Sent("/resultaten");
+        Assert.Equal("http://openzaak/zaken/api/v1/resultaten", resultaat.Request.RequestUri!.ToString());
+        Assert.Equal("Bearer", resultaat.Request.Headers.Authorization!.Scheme);
+        Assert.Contains("\"zaak\":\"" + ZaakUrl + "\"", resultaat.Body);
+        Assert.Contains("\"resultaattype\":\"http://openzaak/catalogi/api/v1/resultaattypen/1\"", resultaat.Body);
+        Assert.True(resultaat.Length > 0);
+
+        var status = rec.Sent("/statussen");
+        Assert.Equal("http://openzaak/zaken/api/v1/statussen", status.Request.RequestUri!.ToString());
+        Assert.Equal("Bearer", status.Request.Headers.Authorization!.Scheme);
+        Assert.Contains("\"zaak\":\"" + ZaakUrl + "\"", status.Body);
+        // The isEindstatus-flagged statustype (/1) is chosen — even though /2 has a higher volgnummer.
+        Assert.Contains("\"statustype\":\"http://openzaak/catalogi/api/v1/statustypen/1\"", status.Body);
+        Assert.Contains("\"datumStatusGezet\":\"2026-06-04T00:00:00Z\"", status.Body);
+        // Bodies are buffered (Content-Length set), so uwsgi doesn't get a chunked body.
+        Assert.True(status.Length > 0);
+    }
+
+    [Fact]
+    public async Task Approving_falls_back_to_the_highest_volgnummer_when_no_eindstatus_is_flagged()
+    {
+        var rec = new Recorder();
+
+        await Gateway(ApprovalStub(rec, new OzRoutes { StatustypenJson = StatustypenPage(withEindstatusFlag: false) }))
+            .SetZaakToEindstatusAsync(new Uri(ZaakUrl), Zaaktype, new DateOnly(2026, 6, 4));
+
+        // No isEindstatus flag → the highest volgnummer (/2) is chosen.
+        Assert.Contains("\"statustype\":\"http://openzaak/catalogi/api/v1/statustypen/2\"", rec.Sent("/statussen").Body);
+    }
+
+    [Fact]
+    public async Task Approving_throws_when_the_zaaktype_has_no_statustypen()
+    {
+        var rec = new Recorder();
+
+        // A page with no `results` property (Results is null) — the eindstatus cannot be resolved.
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(() =>
+            Gateway(ApprovalStub(rec, new OzRoutes { StatustypenJson = "{}" }))
+                .SetZaakToEindstatusAsync(new Uri(ZaakUrl), Zaaktype, new DateOnly(2026, 6, 4)));
+
+        Assert.Contains("No statustypen found", ex.Message);
+        // It never posts anything when it cannot resolve the eindstatus.
+        Assert.Single(rec.Requests);
+    }
+
+    [Fact]
+    public async Task Approving_throws_when_the_statustypen_response_is_empty()
+    {
+        var rec = new Recorder();
+
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(() =>
+            Gateway(ApprovalStub(rec, new OzRoutes { StatustypenJson = "null" }))
+                .SetZaakToEindstatusAsync(new Uri(ZaakUrl), Zaaktype, new DateOnly(2026, 6, 4)));
+
+        Assert.Contains("empty statustypen", ex.Message);
+        Assert.Single(rec.Requests);
+    }
+
+    [Fact]
+    public async Task Approving_throws_when_the_statustypen_query_fails()
+    {
+        var rec = new Recorder();
+
+        var ex = await Assert.ThrowsAsync<HttpRequestException>(() =>
+            Gateway(ApprovalStub(rec, new OzRoutes { StatustypenStatus = HttpStatusCode.InternalServerError }))
+                .SetZaakToEindstatusAsync(new Uri(ZaakUrl), Zaaktype, new DateOnly(2026, 6, 4)));
+
+        Assert.Contains("Querying statustypen", ex.Message);
+    }
+
+    [Fact]
+    public async Task Approving_throws_when_the_resultaattypen_query_fails()
+    {
+        var rec = new Recorder();
+
+        var ex = await Assert.ThrowsAsync<HttpRequestException>(() =>
+            Gateway(ApprovalStub(rec, new OzRoutes { ResultaattypenStatus = HttpStatusCode.InternalServerError }))
+                .SetZaakToEindstatusAsync(new Uri(ZaakUrl), Zaaktype, new DateOnly(2026, 6, 4)));
+
+        Assert.Contains("Querying resultaattypen", ex.Message);
+        Assert.Equal(-1, rec.IndexOf("/resultaten"));
+    }
+
+    [Fact]
+    public async Task Approving_throws_when_the_zaaktype_has_no_resultaattype()
+    {
+        var rec = new Recorder();
+
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(() =>
+            Gateway(ApprovalStub(rec, new OzRoutes { ResultaattypenJson = "{}" }))
+                .SetZaakToEindstatusAsync(new Uri(ZaakUrl), Zaaktype, new DateOnly(2026, 6, 4)));
+
+        Assert.Contains("No resultaattypen found", ex.Message);
+        // Resolved the eindstatus + queried resultaattypen, but posted nothing.
+        Assert.Equal(-1, rec.IndexOf("/resultaten"));
+        Assert.Equal(-1, rec.IndexOf("/statussen"));
+    }
+
+    [Fact]
+    public async Task Approving_throws_when_posting_the_resultaat_fails()
+    {
+        var rec = new Recorder();
+
+        var ex = await Assert.ThrowsAsync<HttpRequestException>(() =>
+            Gateway(ApprovalStub(rec, new OzRoutes { ResultaatPostStatus = HttpStatusCode.BadRequest }))
+                .SetZaakToEindstatusAsync(new Uri(ZaakUrl), Zaaktype, new DateOnly(2026, 6, 4)));
+
+        Assert.Contains("Setting the zaak resultaat", ex.Message);
+        // The status is never posted if the resultaat could not be recorded.
+        Assert.Equal(-1, rec.IndexOf("/statussen"));
+    }
+
+    [Fact]
+    public async Task Approving_throws_when_posting_the_status_fails()
+    {
+        var rec = new Recorder();
+
+        var ex = await Assert.ThrowsAsync<HttpRequestException>(() =>
+            Gateway(ApprovalStub(rec, new OzRoutes { StatusPostStatus = HttpStatusCode.BadRequest }))
+                .SetZaakToEindstatusAsync(new Uri(ZaakUrl), Zaaktype, new DateOnly(2026, 6, 4)));
+
+        Assert.Contains("Setting the zaak status", ex.Message);
+        // It got as far as the resultaat + the status POST (4 calls) before failing.
+        Assert.Equal(4, rec.Requests.Count);
+    }
+
+    [Fact]
+    public async Task Reading_a_zaak_returns_its_identificatie_with_bearer_and_crs()
+    {
+        RequestCapture? capture = null;
+        var handler = new StubHandler(req =>
+        {
+            capture = new RequestCapture { Seen = req };
+            return Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK)
+            {
+                Content = JsonContent.Create(new { identificatie = "REG-XYZ", url = ZaakUrl }),
+            });
+        });
+
+        var reference = await Gateway(handler).GetZaakIdentificatieAsync(new Uri(ZaakUrl));
+
+        Assert.Equal("REG-XYZ", reference);
+        Assert.Equal(HttpMethod.Get, capture!.Seen!.Method);
+        Assert.Equal(ZaakUrl, capture.Seen.RequestUri!.ToString());
+        Assert.Equal("Bearer", capture.Seen.Headers.Authorization!.Scheme);
+        Assert.Equal("EPSG:4326", Assert.Single(capture.Seen.Headers.GetValues("Accept-Crs")));
+    }
+
+    [Fact]
+    public async Task Reading_a_zaak_throws_when_openzaak_rejects_it()
+    {
+        var handler = new StubHandler(_ =>
+            Task.FromResult(new HttpResponseMessage(HttpStatusCode.NotFound) { Content = new StringContent("nope") }));
+
+        var ex = await Assert.ThrowsAsync<HttpRequestException>(
+            () => Gateway(handler).GetZaakIdentificatieAsync(new Uri(ZaakUrl)));
+        Assert.Contains("Reading the zaak", ex.Message);
+    }
+
+    [Fact]
+    public async Task Reading_a_zaak_throws_when_openzaak_returns_an_empty_body()
+    {
+        var handler = new StubHandler(_ =>
+            Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK)
+            {
+                Content = new StringContent("null", System.Text.Encoding.UTF8, "application/json"),
+            }));
+
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(
+            () => Gateway(handler).GetZaakIdentificatieAsync(new Uri(ZaakUrl)));
+        Assert.Contains("empty zaak response", ex.Message);
+    }
+
+    [Fact]
+    public async Task Reading_a_null_zaak_is_rejected()
+    {
+        var handler = new StubHandler(_ => throw new InvalidOperationException("should not be sent"));
+
+        await Assert.ThrowsAsync<ArgumentNullException>(() => Gateway(handler).GetZaakIdentificatieAsync(null!));
+    }
+
+    [Fact]
+    public async Task Approving_rejects_a_null_zaak_or_zaaktype()
+    {
+        var handler = new StubHandler(_ => throw new InvalidOperationException("should not be sent"));
+
+        await Assert.ThrowsAsync<ArgumentNullException>(() =>
+            Gateway(handler).SetZaakToEindstatusAsync(null!, Zaaktype, new DateOnly(2026, 6, 4)));
+        await Assert.ThrowsAsync<ArgumentNullException>(() =>
+            Gateway(handler).SetZaakToEindstatusAsync(new Uri(ZaakUrl), null!, new DateOnly(2026, 6, 4)));
+    }
+
     // ZGW tokens are base64url with padding stripped (ZgwToken.B64Url); restore it to decode.
     private static string DecodeSegment(string segment)
     {

services/bff/Bff.Api/DownstreamClients.cs

@@ -6,16 +6,27 @@ namespace Bff.Api;
 public sealed record SubmitAccepted(string RegistrationId, string Status);
 
 /// <summary>A projection row as the projection-api serves it. <c>Bsn</c>/<c>NaamPlaceholder</c> are
-/// read but never surfaced by the openbaar endpoint (public-safe filtering, ADR-0010/S-09).</summary>
+/// read but never surfaced by the openbaar endpoint (public-safe filtering, ADR-0010/S-09).
-public sealed record ProjectionEntry(string Id, string Status, string? Bsn, string? NaamPlaceholder);
+/// <c>Reference</c> is the public-safe citizen reference (the zaak identificatie, #78).</summary>
+public sealed record ProjectionEntry(string Id, string Status, string? Reference, string? Bsn, string? NaamPlaceholder);
 
 /// <summary>A public-safe openbaar register row — only non-sensitive fields leave the BFF.</summary>
-public sealed record OpenbaarEntry(string Id, string Status);
+public sealed record OpenbaarEntry(string Id, string Status, string? Reference);
+
+/// <summary>A behandelaar's werkbak row: a registration awaiting beoordeling, with the bsn + status a
+/// behandelaar sees (staff view — reached only behind medewerker/behandelaar authorization, S-12c).</summary>
+public sealed record WerkbakItem(string RegistrationId, string Bsn, string Status);
 
 /// <summary>Port to the Domain Service (§8.3: the BFF is the portals' only backend; it fans out).</summary>
 public interface IDomainClient
 {
     Task<SubmitAccepted> SubmitRegistrationAsync(string bsn, CancellationToken ct = default);
+
+    /// <summary>The behandelaar's werkbak — registrations awaiting beoordeling.</summary>
+    Task<IReadOnlyList<WerkbakItem>> GetWerkbakAsync(CancellationToken ct = default);
+
+    /// <summary>Apply a behandelaar's decision (<c>goedkeuren</c>/<c>afwijzen</c>) to a registration.</summary>
+    Task DecideAsync(string registrationId, string besluit, CancellationToken ct = default);
 }
 
 /// <summary>Port to the read projection.</summary>
@@ -36,6 +47,16 @@ public sealed class DomainClient(HttpClient http) : IDomainClient
         return new SubmitAccepted(dto.RegistrationId, dto.Status);
     }
 
+    public async Task<IReadOnlyList<WerkbakItem>> GetWerkbakAsync(CancellationToken ct = default)
+        => await http.GetFromJsonAsync<List<WerkbakItem>>("behandel/werkbak", ct) ?? [];
+
+    public async Task DecideAsync(string registrationId, string besluit, CancellationToken ct = default)
+    {
+        using var response = await http.PostAsJsonAsync(
+            $"registrations/{registrationId}/decide", new { besluit }, ct);
+        response.EnsureSuccessStatusCode();
+    }
+
     private sealed record DomainResponse(string RegistrationId, string Status, string? ZaakUrl);
 }
 

services/bff/Bff.Api/OpenbaarProjection.cs

@@ -11,8 +11,10 @@ public static class OpenbaarProjection
     {
         var filtered = string.IsNullOrWhiteSpace(q)
             ? entries
-            : entries.Where(e => e.Id.Contains(q, StringComparison.OrdinalIgnoreCase));
+            : entries.Where(e =>
+                e.Id.Contains(q, StringComparison.OrdinalIgnoreCase) ||
+                (e.Reference?.Contains(q, StringComparison.OrdinalIgnoreCase) ?? false));
 
-        return [.. filtered.Select(e => new OpenbaarEntry(e.Id, e.Status))];
+        return [.. filtered.Select(e => new OpenbaarEntry(e.Id, e.Status, e.Reference))];
     }
 }

services/bff/Bff.Api/Program.cs

@@ -1,4 +1,6 @@
 using System.Security.Claims;
+using System.Text.Json;
+using System.Text.Json.Serialization;
 using Bff.Api;
 using Microsoft.AspNetCore.Authentication.JwtBearer;
 
@@ -6,6 +8,10 @@ var builder = WebApplication.CreateBuilder(args);
 
 var keycloakAuthority = builder.Configuration["Keycloak:Authority"]
     ?? throw new InvalidOperationException("Missing configuration 'Keycloak:Authority'");
+// Behandelaars authenticate against a *different* Keycloak realm (medewerker) than citizens (digid),
+// so the BFF validates a second issuer for the behandel endpoints (ADR-0013).
+var medewerkerAuthority = builder.Configuration["Keycloak:MedewerkerAuthority"]
+    ?? throw new InvalidOperationException("Missing configuration 'Keycloak:MedewerkerAuthority'");
 var domainBaseUrl = builder.Configuration["Downstream:Domain:BaseUrl"]
     ?? throw new InvalidOperationException("Missing configuration 'Downstream:Domain:BaseUrl'");
 var projectionBaseUrl = builder.Configuration["Downstream:Projection:BaseUrl"]
@@ -19,8 +25,28 @@ builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
         options.Authority = keycloakAuthority;
         options.RequireHttpsMetadata = false;
         options.TokenValidationParameters.ValidateAudience = false;
+    })
+    // The medewerker realm — behandel endpoints only. On validation we lift Keycloak's realm roles
+    // (the nested realm_access.roles claim) into role claims so authorization policies can require them.
+    .AddJwtBearer(BehandelAuth.Scheme, options =>
+    {
+        options.Authority = medewerkerAuthority;
+        options.RequireHttpsMetadata = false;
+        options.TokenValidationParameters.ValidateAudience = false;
+        options.Events = new JwtBearerEvents
+        {
+            OnTokenValidated = context =>
+            {
+                BehandelAuth.AddRealmRoles(context.Principal);
+                return Task.CompletedTask;
+            },
+        };
     });
-builder.Services.AddAuthorization();
+builder.Services.AddAuthorization(options =>
+    options.AddPolicy(BehandelAuth.Policy, policy => policy
+        .AddAuthenticationSchemes(BehandelAuth.Scheme)
+        .RequireAuthenticatedUser()
+        .RequireRole(BehandelAuth.BehandelaarRole)));
 
 // The BFF is the portals' only backend; it fans out to the domain and projection (§8.3).
 builder.Services.AddHttpClient<IDomainClient, DomainClient>(c => c.BaseAddress = new Uri(domainBaseUrl));
@@ -68,7 +94,79 @@ app.MapGet("/openbaar/register", async (string? q, IProjectionClient projection,
 })
     .Produces<IReadOnlyList<OpenbaarEntry>>(StatusCodes.Status200OK);
 
+// Behandelaar's werkbak: registrations awaiting beoordeling. Reached only with a medewerker-realm
+// token carrying the behandelaar role; the BFF proxies the domain's werkbak (staff view, ADR-0013).
+app.MapGet("/behandel/werkbak", async (IDomainClient domain, CancellationToken ct) =>
+    Results.Ok(await domain.GetWerkbakAsync(ct)))
+    .RequireAuthorization(BehandelAuth.Policy)
+    .Produces<IReadOnlyList<WerkbakItem>>(StatusCodes.Status200OK)
+    .Produces(StatusCodes.Status401Unauthorized)
+    .Produces(StatusCodes.Status403Forbidden);
+
+// A behandelaar's beoordeling on a registration (goedkeuren/afwijzen). Forwarded to the domain, which
+// applies the decision and completes the workflow task (ADR-0013). Same medewerker/behandelaar gate.
+app.MapPost("/behandel/registrations/{id}/decide",
+    async (string id, DecideRequest body, IDomainClient domain, CancellationToken ct) =>
+    {
+        if (!BehandelAuth.IsKnownBesluit(body.Besluit))
+            return Results.BadRequest(new { error = $"Unknown besluit '{body.Besluit}'. Expected 'goedkeuren' or 'afwijzen'." });
+
+        await domain.DecideAsync(id, body.Besluit, ct);
+        return Results.NoContent();
+    })
+    .RequireAuthorization(BehandelAuth.Policy)
+    .Produces(StatusCodes.Status204NoContent)
+    .Produces(StatusCodes.Status400BadRequest)
+    .Produces(StatusCodes.Status401Unauthorized)
+    .Produces(StatusCodes.Status403Forbidden);
+
 app.Run();
 
+/// <summary>The behandelaar's decision on a registration.</summary>
+public sealed record DecideRequest(string Besluit);
+
+// Behandel (medewerker-realm) authentication + authorization wiring (ADR-0013).
+internal static class BehandelAuth
+{
+    public const string Scheme = "medewerker";
+    public const string Policy = "behandelaar";
+    public const string BehandelaarRole = "behandelaar";
+
+    /// <summary>The beoordeling vocabulary the BFF accepts (case-insensitive); an unknown besluit is a
+    /// 400 without troubling the domain. Mirrors the domain's <c>BeoordelingsBesluit</c>.</summary>
+    public static bool IsKnownBesluit(string? besluit) =>
+        string.Equals(besluit, "goedkeuren", StringComparison.OrdinalIgnoreCase) ||
+        string.Equals(besluit, "afwijzen", StringComparison.OrdinalIgnoreCase);
+
+    /// <summary>Lift Keycloak's realm roles (the nested <c>realm_access.roles</c> claim) onto the
+    /// principal as role claims, so <c>RequireRole</c> can authorize on them.</summary>
+    public static void AddRealmRoles(ClaimsPrincipal? principal)
+    {
+        if (principal?.Identity is not ClaimsIdentity identity)
+            return;
+
+        var realmAccess = principal.FindFirst("realm_access")?.Value;
+        if (string.IsNullOrWhiteSpace(realmAccess))
+            return;
+
+        // A malformed realm_access claim must not fail authentication (a throw here becomes a 401);
+        // it simply yields no roles, so the authorization policy answers 403.
+        string[] roles;
+        try
+        {
+            roles = JsonSerializer.Deserialize<RealmAccess>(realmAccess)?.Roles ?? [];
+        }
+        catch (JsonException)
+        {
+            return;
+        }
+
+        foreach (var role in roles)
+            identity.AddClaim(new Claim(identity.RoleClaimType, role));
+    }
+
+    private sealed record RealmAccess([property: JsonPropertyName("roles")] string[] Roles);
+}
+
 // Exposed so the test host (WebApplicationFactory<Program>) can boot the app.
 public partial class Program;

services/bff/Bff.Api/appsettings.json

@@ -7,7 +7,8 @@
   },
   "AllowedHosts": "*",
   "Keycloak": {
-    "Authority": "http://localhost:8180/realms/digid"
+    "Authority": "http://localhost:8180/realms/digid",
+    "MedewerkerAuthority": "http://localhost:8180/realms/medewerker"
   },
   "Downstream": {
     "Domain": { "BaseUrl": "http://localhost:8130/" },

services/bff/Bff.Tests/BehandelEndpointTests.cs

@@ -0,0 +1,114 @@
+using System.Net;
+using System.Net.Http.Headers;
+using System.Net.Http.Json;
+using Bff.Api;
+
+namespace Bff.Tests;
+
+/// <summary>
+/// The behandel werkbak endpoint (S-12c): reached only with a medewerker-realm token that carries the
+/// <c>behandelaar</c> role. A missing token is 401; an authenticated medewerker without the role is
+/// 403; a behandelaar gets the werkbak (staff view, incl. bsn).
+/// </summary>
+public class BehandelEndpointTests
+{
+    private static HttpRequestMessage Werkbak(string? bearer)
+    {
+        var request = new HttpRequestMessage(HttpMethod.Get, "/behandel/werkbak");
+        if (bearer is not null)
+            request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", bearer);
+        return request;
+    }
+
+    [Fact]
+    public async Task Rejects_the_werkbak_without_a_token()
+    {
+        using var factory = new BffFactory();
+
+        var response = await factory.CreateClient().SendAsync(Werkbak(bearer: null));
+
+        Assert.Equal(HttpStatusCode.Unauthorized, response.StatusCode);
+    }
+
+    [Fact]
+    public async Task Rejects_a_medewerker_without_the_behandelaar_role()
+    {
+        using var factory = new BffFactory();
+
+        var response = await factory.CreateClient().SendAsync(Werkbak(TestTokens.Medewerker("teamlead")));
+
+        Assert.Equal(HttpStatusCode.Forbidden, response.StatusCode);
+    }
+
+    [Fact]
+    public async Task Serves_the_werkbak_to_a_behandelaar()
+    {
+        using var factory = new BffFactory();
+        factory.Domain.Werkbak.Add(new WerkbakItem("reg-1", "123456782", "InBehandeling"));
+
+        var response = await factory.CreateClient().SendAsync(Werkbak(TestTokens.Medewerker("behandelaar")));
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        var items = await response.Content.ReadFromJsonAsync<List<WerkbakItem>>();
+        var item = Assert.Single(items!);
+        Assert.Equal("reg-1", item.RegistrationId);
+        Assert.Equal("123456782", item.Bsn);
+    }
+
+    private static HttpRequestMessage Decide(string? bearer, string id = "reg-1", string besluit = "goedkeuren")
+    {
+        var request = new HttpRequestMessage(HttpMethod.Post, $"/behandel/registrations/{id}/decide")
+        {
+            Content = JsonContent.Create(new { besluit }),
+        };
+        if (bearer is not null)
+            request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", bearer);
+        return request;
+    }
+
+    [Fact]
+    public async Task Rejects_a_decision_without_a_token()
+    {
+        using var factory = new BffFactory();
+
+        var response = await factory.CreateClient().SendAsync(Decide(bearer: null));
+
+        Assert.Equal(HttpStatusCode.Unauthorized, response.StatusCode);
+        Assert.Null(factory.Domain.Decided);
+    }
+
+    [Fact]
+    public async Task Rejects_a_decision_from_a_medewerker_without_the_behandelaar_role()
+    {
+        using var factory = new BffFactory();
+
+        var response = await factory.CreateClient().SendAsync(Decide(TestTokens.Medewerker("teamlead")));
+
+        Assert.Equal(HttpStatusCode.Forbidden, response.StatusCode);
+        Assert.Null(factory.Domain.Decided);
+    }
+
+    [Fact]
+    public async Task Forwards_a_behandelaar_decision_to_the_domain()
+    {
+        using var factory = new BffFactory();
+
+        var response = await factory.CreateClient()
+            .SendAsync(Decide(TestTokens.Medewerker("behandelaar"), id: "reg-42", besluit: "afwijzen"));
+
+        Assert.Equal(HttpStatusCode.NoContent, response.StatusCode);
+        Assert.Equal(("reg-42", "afwijzen"), factory.Domain.Decided);
+    }
+
+    [Fact]
+    public async Task Rejects_an_unknown_besluit_without_calling_the_domain()
+    {
+        using var factory = new BffFactory();
+
+        var response = await factory.CreateClient()
+            .SendAsync(Decide(TestTokens.Medewerker("behandelaar"), besluit: "misschien"));
+
+        Assert.Equal(HttpStatusCode.BadRequest, response.StatusCode);
+        Assert.Null(factory.Domain.Decided);
+    }
+}

services/bff/Bff.Tests/BffFactory.cs

@@ -5,6 +5,7 @@ using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Mvc.Testing;
 using Microsoft.AspNetCore.TestHost;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.IdentityModel.Protocols;
 using Microsoft.IdentityModel.Protocols.OpenIdConnect;
 using Microsoft.IdentityModel.Tokens;
 
@@ -23,24 +24,19 @@ internal sealed class BffFactory : WebApplicationFactory<Program>
     public FakeDomainClient Domain { get; } = new();
     public FakeProjectionClient Projection { get; } = new();
 
-    protected override void ConfigureWebHost(IWebHostBuilder builder)
+    private static void ValidateWithTestKey(IServiceCollection services, string scheme) =>
+        services.Configure<JwtBearerOptions>(scheme, options =>
         {
-        builder.UseSetting("Keycloak:Authority", "https://keycloak.invalid/realms/digid");
+            // Validate locally against the test key and NEVER reach out for OIDC metadata. A static
-        builder.UseSetting("Downstream:Domain:BaseUrl", "http://domain.invalid/");
+            // configuration manager guarantees this regardless of Configure/PostConfigure ordering —
-        builder.UseSetting("Downstream:Projection:BaseUrl", "http://projection.invalid/");
+            // clearing Authority alone left the medewerker scheme fetching metadata under CI timing
-
+            // (2s hang → 401), because JwtBearer's PostConfigure could still build a ConfigurationManager.
-        builder.ConfigureTestServices(services =>
-        {
-            services.AddSingleton<IDomainClient>(Domain);
-            services.AddSingleton<IProjectionClient>(Projection);
-
-            services.Configure<JwtBearerOptions>(JwtBearerDefaults.AuthenticationScheme, options =>
-            {
-                // Validate locally against the test key; never reach out for OIDC metadata.
             options.Authority = null;
             options.MetadataAddress = null!;
             options.RequireHttpsMetadata = false;
             options.Configuration = new OpenIdConnectConfiguration();
+            options.ConfigurationManager =
+                new StaticConfigurationManager<OpenIdConnectConfiguration>(new OpenIdConnectConfiguration());
             options.TokenValidationParameters = new TokenValidationParameters
             {
                 ValidateIssuer = false,
@@ -51,6 +47,24 @@ internal sealed class BffFactory : WebApplicationFactory<Program>
                 ClockSkew = TimeSpan.Zero,
             };
         });
+
+    protected override void ConfigureWebHost(IWebHostBuilder builder)
+    {
+        builder.UseSetting("Keycloak:Authority", "https://keycloak.invalid/realms/digid");
+        builder.UseSetting("Keycloak:MedewerkerAuthority", "https://keycloak.invalid/realms/medewerker");
+        builder.UseSetting("Downstream:Domain:BaseUrl", "http://domain.invalid/");
+        builder.UseSetting("Downstream:Projection:BaseUrl", "http://projection.invalid/");
+
+        builder.ConfigureTestServices(services =>
+        {
+            services.AddSingleton<IDomainClient>(Domain);
+            services.AddSingleton<IProjectionClient>(Projection);
+
+            // Both realms validate locally against the test key (no live Keycloak). The medewerker
+            // scheme keeps its OnTokenValidated role-lifting from Program.cs — only the validation
+            // parameters are swapped here.
+            ValidateWithTestKey(services, JwtBearerDefaults.AuthenticationScheme);
+            ValidateWithTestKey(services, "medewerker");
         });
     }
 }
@@ -60,12 +74,24 @@ internal sealed class FakeDomainClient : IDomainClient
 {
     public string? SubmittedBsn { get; private set; }
     public SubmitAccepted Result { get; set; } = new("reg-123", "Ingediend");
+    public List<WerkbakItem> Werkbak { get; } = [];
 
     public Task<SubmitAccepted> SubmitRegistrationAsync(string bsn, CancellationToken ct = default)
     {
         SubmittedBsn = bsn;
         return Task.FromResult(Result);
     }
+
+    public (string RegistrationId, string Besluit)? Decided { get; private set; }
+
+    public Task<IReadOnlyList<WerkbakItem>> GetWerkbakAsync(CancellationToken ct = default)
+        => Task.FromResult<IReadOnlyList<WerkbakItem>>(Werkbak);
+
+    public Task DecideAsync(string registrationId, string besluit, CancellationToken ct = default)
+    {
+        Decided = (registrationId, besluit);
+        return Task.CompletedTask;
+    }
 }
 
 /// <summary>Serves a configurable set of projection rows.</summary>

services/bff/Bff.Tests/OpenbaarEndpointTests.cs

@@ -10,7 +10,7 @@ public class OpenbaarEndpointTests
     public async Task Serves_public_safe_rows_anonymously()
     {
         using var factory = new BffFactory();
-        factory.Projection.Entries.Add(new ProjectionEntry("abc-111", "INGEDIEND", "123456782", "Jan"));
+        factory.Projection.Entries.Add(new ProjectionEntry("abc-111", "INGEDIEND", "REG-abc", "123456782", "Jan"));
 
         // No Authorization header — the openbaar register is a public lookup (ADR-0010/S-09).
         var response = await factory.CreateClient().GetAsync("/openbaar/register");
@@ -19,7 +19,9 @@ public class OpenbaarEndpointTests
         var body = await response.Content.ReadAsStringAsync();
         Assert.Contains("abc-111", body);
         Assert.Contains("INGEDIEND", body);
-        // The bsn must never appear in a public response.
+        // The public reference is surfaced (matches the submit confirmation, #78)...
+        Assert.Contains("REG-abc", body);
+        // ...but the bsn must never appear in a public response.
         Assert.DoesNotContain("123456782", body);
     }
 
@@ -27,8 +29,8 @@ public class OpenbaarEndpointTests
     public async Task Filters_by_the_query_parameter()
     {
         using var factory = new BffFactory();
-        factory.Projection.Entries.Add(new ProjectionEntry("abc-111", "INGEDIEND", null, null));
+        factory.Projection.Entries.Add(new ProjectionEntry("abc-111", "INGEDIEND", "REG-abc", null, null));
-        factory.Projection.Entries.Add(new ProjectionEntry("def-222", "INGEDIEND", null, null));
+        factory.Projection.Entries.Add(new ProjectionEntry("def-222", "INGEDIEND", "REG-def", null, null));
 
         var rows = await factory.CreateClient()
             .GetFromJsonAsync<List<OpenbaarEntry>>("/openbaar/register?q=abc");

services/bff/Bff.Tests/OpenbaarProjectionTests.cs

@@ -6,8 +6,8 @@ public class OpenbaarProjectionTests
 {
     private static readonly ProjectionEntry[] Sample =
     [
-        new("abc-111", "INGEDIEND", "123456782", "Jan"),
+        new("abc-111", "INGEDIEND", Reference: "REG-A", Bsn: "123456782", NaamPlaceholder: "Jan"),
-        new("def-222", "INGEDIEND", "987654321", "Piet"),
+        new("def-222", "INGESCHREVEN", Reference: "REG-B", Bsn: "987654321", NaamPlaceholder: "Piet"),
     ];
 
     [Fact]
@@ -18,31 +18,47 @@ public class OpenbaarProjectionTests
         Assert.Equal(2, view.Count);
         Assert.Equal("abc-111", view[0].Id);
         Assert.Equal("INGEDIEND", view[0].Status);
+        // The public reference (zaak identificatie) is surfaced so it matches the submit confirmation (#78).
+        Assert.Equal("REG-A", view[0].Reference);
     }
 
     [Fact]
-    public void Public_view_exposes_only_id_and_status()
+    public void Public_view_exposes_only_id_status_and_reference()
     {
-        // OpenbaarEntry structurally carries only Id + Status — bsn/naam can never leak.
+        // OpenbaarEntry structurally carries only public-safe fields — bsn/naam can never leak.
         var props = typeof(OpenbaarEntry).GetProperties().Select(p => p.Name).ToArray();
-        Assert.Equal(["Id", "Status"], props);
+        Assert.Equal(["Id", "Status", "Reference"], props);
     }
 
     [Theory]
-    [InlineData("abc", 1)]
+    [InlineData("abc", 1)]   // by id
-    [InlineData("ABC", 1)]
+    [InlineData("ABC", 1)]   // by id, case-insensitive
-    [InlineData("2", 1)]
+    [InlineData("def", 1)]   // by id
-    [InlineData("zzz", 0)]
+    [InlineData("zzz", 0)]   // no match
     public void Filters_by_id_containing_the_query_case_insensitively(string q, int expected)
-    {
+        => Assert.Equal(expected, OpenbaarProjection.PublicView(Sample, q).Count);
-        var view = OpenbaarProjection.PublicView(Sample, q);
 
-        Assert.Equal(expected, view.Count);
+    [Theory]
-    }
+    [InlineData("REG-A", 1)] // by reference — the citizen's confirmation reference
+    [InlineData("reg-a", 1)] // by reference, case-insensitive
+    [InlineData("REG", 2)]   // both share the prefix
+    public void Filters_by_reference_containing_the_query_case_insensitively(string q, int expected)
+        => Assert.Equal(expected, OpenbaarProjection.PublicView(Sample, q).Count);
 
     [Fact]
     public void Blank_query_is_treated_as_no_filter()
     {
         Assert.Equal(2, OpenbaarProjection.PublicView(Sample, "   ").Count);
     }
+
+    [Fact]
+    public void A_row_without_a_reference_never_matches_a_query()
+    {
+        // Older rows can have a null reference (the column is additive, #78/ADR-0012). A search must
+        // simply not match them — it must not throw and must not treat "no reference" as a match.
+        var entries = new[] { new ProjectionEntry("xyz-999", "INGEDIEND", Reference: null, Bsn: null, NaamPlaceholder: null) };
+
+        Assert.Empty(OpenbaarProjection.PublicView(entries, "REG"));
+        Assert.Equal("xyz-999", Assert.Single(OpenbaarProjection.PublicView(entries, "xyz")).Id);
+    }
 }

services/bff/Bff.Tests/TestTokens.cs

@@ -17,6 +17,22 @@ internal static class TestTokens
         new SymmetricSecurityKey(Encoding.UTF8.GetBytes("a-different-signing-key-256-bits-long-indeed-yes!")),
         expired: false);
 
+    /// <summary>A medewerker-realm token carrying the given realm roles under <c>realm_access.roles</c>
+    /// (Keycloak's shape), signed with the valid test key. Used to exercise behandel authorization.</summary>
+    public static string Medewerker(params string[] roles)
+    {
+        var handler = new JsonWebTokenHandler();
+        return handler.CreateToken(new SecurityTokenDescriptor
+        {
+            Claims = new Dictionary<string, object>
+            {
+                ["realm_access"] = new Dictionary<string, object> { ["roles"] = roles },
+            },
+            Expires = DateTime.UtcNow.AddMinutes(30),
+            SigningCredentials = new SigningCredentials(BffFactory.TestSigningKey, SecurityAlgorithms.HmacSha256),
+        });
+    }
+
     private static string Create(string bsn, SymmetricSecurityKey key, bool expired)
     {
         var handler = new JsonWebTokenHandler();

services/bff/openapi.json

@@ -60,14 +60,95 @@
           }
         }
       }
+    },
+    "/behandel/werkbak": {
+      "get": {
+        "tags": [
+          "Bff.Api"
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "array",
+                  "items": {
+                    "$ref": "#/components/schemas/WerkbakItem"
+                  }
+                }
+              }
+            }
+          },
+          "401": {
+            "description": "Unauthorized"
+          },
+          "403": {
+            "description": "Forbidden"
+          }
+        }
+      }
+    },
+    "/behandel/registrations/{id}/decide": {
+      "post": {
+        "tags": [
+          "Bff.Api"
+        ],
+        "parameters": [
+          {
+            "name": "id",
+            "in": "path",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          }
+        ],
+        "requestBody": {
+          "content": {
+            "application/json": {
+              "schema": {
+                "$ref": "#/components/schemas/DecideRequest"
+              }
+            }
+          },
+          "required": true
+        },
+        "responses": {
+          "204": {
+            "description": "No Content"
+          },
+          "400": {
+            "description": "Bad Request"
+          },
+          "401": {
+            "description": "Unauthorized"
+          },
+          "403": {
+            "description": "Forbidden"
+          }
+        }
+      }
     }
   },
   "components": {
     "schemas": {
+      "DecideRequest": {
+        "required": [
+          "besluit"
+        ],
+        "type": "object",
+        "properties": {
+          "besluit": {
+            "type": "string"
+          }
+        }
+      },
       "OpenbaarEntry": {
         "required": [
           "id",
-          "status"
+          "status",
+          "reference"
         ],
         "type": "object",
         "properties": {
@@ -76,6 +157,12 @@
           },
           "status": {
             "type": "string"
+          },
+          "reference": {
+            "type": [
+              "null",
+              "string"
+            ]
           }
         }
       },
@@ -93,6 +180,25 @@
             "type": "string"
           }
         }
+      },
+      "WerkbakItem": {
+        "required": [
+          "registrationId",
+          "bsn",
+          "status"
+        ],
+        "type": "object",
+        "properties": {
+          "registrationId": {
+            "type": "string"
+          },
+          "bsn": {
+            "type": "string"
+          },
+          "status": {
+            "type": "string"
+          }
+        }
       }
     }
   },

services/domain/Big.Api/Program.cs

@@ -20,10 +20,13 @@ builder.Services.AddSingleton<IRegistrationStore, InMemoryRegistrationStore>();
 builder.Services.AddHttpClient<FlowableWorkflowClient>();
 builder.Services.AddTransient<IWorkflowClient>(sp => sp.GetRequiredService<FlowableWorkflowClient>());
 builder.Services.AddTransient<IExternalWorkerClient>(sp => sp.GetRequiredService<FlowableWorkflowClient>());
+builder.Services.AddTransient<IUserTaskClient>(sp => sp.GetRequiredService<FlowableWorkflowClient>());
 builder.Services.AddHttpClient<IAclClient, AclHttpClient>();
 
 builder.Services.AddScoped<SubmitRegistration>();
 builder.Services.AddScoped<ApproveRegistration>();
+builder.Services.AddScoped<BeoordeelRegistratie>();
+builder.Services.AddScoped<Werkbak>();
 builder.Services.AddScoped<OpenZaakWorker>();
 builder.Services.AddScoped<OpenZaakJobProcessor>();
 
@@ -55,6 +58,28 @@ app.MapPost("/registrations/{id}/approve", async (string id, ApproveRegistration
     return Results.NoContent();
 });
 
+// The behandelaar's beoordeling (S-12): decide a registration goedkeuren (→ INGESCHREVEN, sets the
+// zaak's final status via the ACL) or afwijzen (→ AFGEWEZEN). Idempotent. This is the domain contract
+// the behandel-portal's decision reaches through the BFF; it supersedes the temporary /approve above,
+// which is retired once the portal lands.
+app.MapPost("/registrations/{id}/decide", async (string id, DecideRequest body, BeoordeelRegistratie beoordeel, CancellationToken ct) =>
+{
+    if (!Guid.TryParse(id, out var guid))
+        return Results.NotFound();
+
+    if (!Enum.TryParse<BeoordelingsBesluit>(body.Besluit, ignoreCase: true, out var besluit))
+        return Results.BadRequest(new { error = $"Unknown besluit '{body.Besluit}'. Expected 'goedkeuren' or 'afwijzen'." });
+
+    await beoordeel.HandleAsync(new BeoordeelRegistratieCommand(new RegistrationId(guid), besluit), ct);
+    return Results.NoContent();
+});
+
+// The behandelaar's werkbak (S-12): the registrations awaiting beoordeling, read from the open
+// Beoordelen user tasks (§8.2) and enriched with bsn + status. The BFF proxies this behind
+// medewerker-realm + behandelaar-role authorization; the domain trusts its callers (§8.3).
+app.MapGet("/behandel/werkbak", async (Werkbak werkbak, CancellationToken ct) =>
+    Results.Ok(await werkbak.GetAsync(ct)));
+
 // Read a registration. Its zaak URL appears once the worker has opened the zaak (eventually).
 app.MapGet("/registrations/{id}", async (string id, IRegistrationStore store, CancellationToken ct) =>
 {
@@ -72,6 +97,8 @@ await app.RunAsync();
 
 public sealed record SubmitRegistrationRequest(string Bsn);
 
+public sealed record DecideRequest(string Besluit);
+
 public sealed record RegistrationResponse(string RegistrationId, string Status, string? ZaakUrl);
 
 public partial class Program;

services/domain/Big.Application/BeoordeelRegistratie.cs

@@ -0,0 +1,71 @@
+using Big.Domain;
+
+namespace Big.Application;
+
+/// <summary>A behandelaar's beoordeling outcome, in domain language.</summary>
+public enum BeoordelingsBesluit
+{
+    /// <summary>Approve — enter the registration in the register.</summary>
+    Goedkeuren,
+
+    /// <summary>Reject — turn the registration down.</summary>
+    Afwijzen,
+}
+
+/// <summary>A behandelaar's decision on a registration.</summary>
+public sealed record BeoordeelRegistratieCommand(RegistrationId RegistrationId, BeoordelingsBesluit Besluit);
+
+/// <summary>
+/// The beoordeling use case (S-12): apply a behandelaar's decision to a registration.
+/// <see cref="BeoordelingsBesluit.Goedkeuren"/> sets the zaak's final status via the ACL (§8.1) and
+/// advances the aggregate to INGESCHREVEN; <see cref="BeoordelingsBesluit.Afwijzen"/> advances it to
+/// AFGEWEZEN in the domain (propagating a rejection to the zaak, so the openbaar projection reflects
+/// it, is a later sub-slice of S-12). After applying the decision it completes the Flowable
+/// <c>Beoordelen</c> task (found by registrationId) so the workflow advances (ADR-0013). Both
+/// decisions are idempotent — a repeated or redelivered decision that matches the current terminal
+/// state is a no-op, so the ACL is not called and the task not completed twice.
+/// </summary>
+public sealed class BeoordeelRegistratie(IRegistrationStore store, IAclClient acl, IUserTaskClient tasks)
+{
+    public async Task HandleAsync(BeoordeelRegistratieCommand command, CancellationToken ct = default)
+    {
+        ArgumentNullException.ThrowIfNull(command);
+
+        var registration = await store.GetAsync(command.RegistrationId, ct)
+            ?? throw new InvalidOperationException($"No registration {command.RegistrationId} to decide.");
+
+        switch (command.Besluit)
+        {
+            case BeoordelingsBesluit.Goedkeuren:
+                // A repeated approval is a no-op: don't set the zaak status a second time.
+                if (registration.Status == RegistrationStatus.Ingeschreven)
+                    return;
+                if (registration.ZaakUrl is null)
+                    throw new InvalidOperationException(
+                        $"Registration {command.RegistrationId} has no zaak yet; it cannot be approved.");
+                await acl.ApproveZaakAsync(registration.ZaakUrl, ct);
+                registration.Approve();
+                break;
+
+            case BeoordelingsBesluit.Afwijzen:
+                if (registration.Status == RegistrationStatus.Afgewezen)
+                    return;
+                registration.Reject();
+                break;
+        }
+
+        await store.SaveAsync(registration, ct);
+        await CompleteWorkflowTaskAsync(command.RegistrationId, command.Besluit, ct);
+    }
+
+    // Advance the workflow: complete the open Beoordelen task for this registration. If none is open
+    // (already completed, or the process hasn't parked yet) the decision still stands — we complete
+    // nothing rather than fail.
+    private async Task CompleteWorkflowTaskAsync(RegistrationId registrationId, BeoordelingsBesluit besluit, CancellationToken ct)
+    {
+        var open = await tasks.GetOpenBeoordelingenAsync(ct);
+        var task = open.FirstOrDefault(t => t.RegistrationId == registrationId);
+        if (task is not null)
+            await tasks.CompleteBeoordelingAsync(task.TaskId, besluit, ct);
+    }
+}

services/domain/Big.Application/OpenZaakWorker.cs

@@ -28,7 +28,7 @@ public sealed class OpenZaakWorker(IRegistrationStore store, IAclClient acl)
         if (registration.ZaakUrl is not null)
             return registration.ZaakUrl;
 
-        var zaakUrl = await acl.OpenZaakAsync(registration.Bsn, ct);
+        var zaakUrl = await acl.OpenZaakAsync(registration.Bsn, registration.Id.ToString(), ct);
         registration.AttachZaak(zaakUrl);
         await store.SaveAsync(registration, ct);
         return zaakUrl;

services/domain/Big.Application/Ports.cs

@@ -24,7 +24,10 @@ public interface IWorkflowClient
 /// </summary>
 public interface IAclClient
 {
-    Task<Uri> OpenZaakAsync(string bsn, CancellationToken ct = default);
+    /// <summary>Open a zaak for the registration. <paramref name="reference"/> is the registration's
+    /// own reference (its id); the ACL records it as the zaak's identificatie so the openbaar register
+    /// can show the same reference the zorgprofessional was given (S-09b follow-up, adr-proposal #78).</summary>
+    Task<Uri> OpenZaakAsync(string bsn, string reference, CancellationToken ct = default);
 
     /// <summary>
     /// Record the approval on the given zaak. The ACL translates this to the ZGW concept — setting
@@ -33,6 +36,30 @@ public interface IAclClient
     Task ApproveZaakAsync(Uri zaakUrl, CancellationToken ct = default);
 }
 
+/// <summary>
+/// The port to the behandelaar's user tasks in the workflow engine (S-12). Implemented by the
+/// Workflow Client — the only code that talks to Flowable (§8.2). The application lists the open
+/// <c>Beoordelen</c> tasks (the werkbak), claims one for a behandelaar, and completes it with the
+/// decision; it never names Flowable's REST shapes.
+/// </summary>
+public interface IUserTaskClient
+{
+    /// <summary>The werkbak: the <c>Beoordelen</c> tasks awaiting a behandelaar, each with the
+    /// registration it belongs to.</summary>
+    Task<IReadOnlyList<BeoordelingTask>> GetOpenBeoordelingenAsync(CancellationToken ct = default);
+
+    /// <summary>Claim a beoordeling task for a behandelaar (assigns it to them).</summary>
+    Task ClaimAsync(string taskId, string behandelaar, CancellationToken ct = default);
+
+    /// <summary>Complete a beoordeling task, carrying the decision into the process as the
+    /// <c>besluit</c> variable so the workflow can continue on the chosen branch.</summary>
+    Task CompleteBeoordelingAsync(string taskId, BeoordelingsBesluit besluit, CancellationToken ct = default);
+}
+
+/// <summary>A <c>Beoordelen</c> user task in the werkbak: the Flowable task id (needed to claim and
+/// complete it) and the registration it carries as a process variable.</summary>
+public sealed record BeoordelingTask(string TaskId, RegistrationId RegistrationId);
+
 /// <summary>
 /// Persistence port for the <see cref="Registration"/> aggregate. In-memory for the minimal slice
 /// (ADR-0009); an EF-backed store is a documented follow-up, and this port keeps that change additive.

services/domain/Big.Application/Werkbak.cs

@@ -0,0 +1,32 @@
+namespace Big.Application;
+
+/// <summary>One row of the behandelaar's werkbak: a registration awaiting beoordeling, with the
+/// public-facing reference (its id) plus the bsn and status a behandelaar needs to triage it.</summary>
+public sealed record WerkbakItem(string RegistrationId, string Bsn, string Status);
+
+/// <summary>
+/// The werkbak query (S-12c): the registrations awaiting a behandelaar's beoordeling. It reads the
+/// open <c>Beoordelen</c> tasks from the workflow engine (§8.2, via <see cref="IUserTaskClient"/>) —
+/// the authoritative set of work items — and enriches each with its aggregate (bsn + status). A task
+/// whose registration the domain doesn't know is skipped rather than invented.
+/// </summary>
+public sealed class Werkbak(IUserTaskClient tasks, IRegistrationStore store)
+{
+    public async Task<IReadOnlyList<WerkbakItem>> GetAsync(CancellationToken ct = default)
+    {
+        var open = await tasks.GetOpenBeoordelingenAsync(ct);
+
+        var items = new List<WerkbakItem>(open.Count);
+        foreach (var task in open)
+        {
+            var registration = await store.GetAsync(task.RegistrationId, ct);
+            if (registration is null)
+                continue;
+
+            items.Add(new WerkbakItem(
+                registration.Id.ToString(), registration.Bsn, registration.Status.ToString()));
+        }
+
+        return items;
+    }
+}

services/domain/Big.Domain/Registration.cs

@@ -66,10 +66,28 @@ public sealed class Registration
     }
 
     /// <summary>
-    /// Approve the registration — the behandelaar's decision to enter it in the register. Advances
+    /// A behandelaar picks the registration up for beoordeling. Advances
-    /// <see cref="RegistrationStatus.Ingediend"/> → <see cref="RegistrationStatus.Ingeschreven"/>.
+    /// <see cref="RegistrationStatus.Ingediend"/> → <see cref="RegistrationStatus.InBehandeling"/>.
-    /// Requires an opened zaak (the approval sets that zaak's status via the ACL), and only a
+    /// Re-taking one already <see cref="RegistrationStatus.InBehandeling"/> is a no-op (the same or
-    /// submitted registration can be approved: re-approving is rejected as an invalid transition.
+    /// another behandelaar re-opens it); a decided registration can no longer be taken into behandeling.
+    /// </summary>
+    public void TakeIntoBehandeling()
+    {
+        if (Status == RegistrationStatus.InBehandeling)
+            return;
+
+        if (Status != RegistrationStatus.Ingediend)
+            throw new InvalidOperationException(
+                $"Registration {Id} is {Status}; only an INGEDIEND registration can be taken into behandeling.");
+
+        Status = RegistrationStatus.InBehandeling;
+    }
+
+    /// <summary>
+    /// Approve the registration — the behandelaar's decision to enter it in the register. Advances a
+    /// submitted or in-behandeling registration to <see cref="RegistrationStatus.Ingeschreven"/>.
+    /// Requires an opened zaak (the approval sets that zaak's status via the ACL); a registration that
+    /// has already been decided cannot be approved again.
     /// </summary>
     public void Approve()
     {
@@ -77,10 +95,27 @@ public sealed class Registration
             throw new InvalidOperationException(
                 $"Registration {Id} has no zaak yet; it cannot be approved before its zaak is opened.");
 
-        if (Status != RegistrationStatus.Ingediend)
+        RequireOpenForDecision(nameof(Approve));
-            throw new InvalidOperationException(
-                $"Registration {Id} is {Status}; only an INGEDIEND registration can be approved.");
-
         Status = RegistrationStatus.Ingeschreven;
     }
+
+    /// <summary>
+    /// Reject the registration — the behandelaar's decision not to enter it in the register. Advances a
+    /// submitted or in-behandeling registration to <see cref="RegistrationStatus.Afgewezen"/>. Unlike
+    /// approval this needs no zaak: a registration can be rejected before or after its zaak is opened.
+    /// A registration that has already been decided cannot be rejected again.
+    /// </summary>
+    public void Reject()
+    {
+        RequireOpenForDecision(nameof(Reject));
+        Status = RegistrationStatus.Afgewezen;
+    }
+
+    // A decision is only valid while the registration is still open (INGEDIEND or IN_BEHANDELING).
+    private void RequireOpenForDecision(string decision)
+    {
+        if (Status is not (RegistrationStatus.Ingediend or RegistrationStatus.InBehandeling))
+            throw new InvalidOperationException(
+                $"Registration {Id} is {Status}; only an INGEDIEND or IN_BEHANDELING registration can be decided ({decision}).");
+    }
 }

services/domain/Big.Domain/RegistrationStatus.cs

@@ -1,13 +1,20 @@
 namespace Big.Domain;
 
-/// <summary>The lifecycle states a <see cref="Registration"/> moves through. The walking
+/// <summary>The lifecycle states a <see cref="Registration"/> moves through. Submission starts in
-/// skeleton knows <see cref="Ingediend"/> and the terminal <see cref="Ingeschreven"/>; withdrawal,
+/// <see cref="Ingediend"/>; a behandelaar takes it <see cref="InBehandeling"/> and decides it into one
-/// beoordeling and herregistratie states arrive in their own slices (Iteration 2+).</summary>
+/// of the terminal states <see cref="Ingeschreven"/> (approved) or <see cref="Afgewezen"/> (rejected).
+/// Withdrawal and herregistratie states arrive in their own slices (S-11+).</summary>
 public enum RegistrationStatus
 {
     /// <summary>Submitted by the zorgprofessional; the registratie process has been started.</summary>
     Ingediend,
 
-    /// <summary>Approved: entered in the register. Terminal in the walking skeleton (S-09b).</summary>
+    /// <summary>Picked up by a behandelaar for beoordeling (S-12).</summary>
+    InBehandeling,
+
+    /// <summary>Approved: entered in the register. Terminal.</summary>
     Ingeschreven,
+
+    /// <summary>Rejected by the behandelaar. Terminal.</summary>
+    Afgewezen,
 }

services/domain/Big.Infrastructure/AclHttpClient.cs

@@ -11,10 +11,10 @@ namespace Big.Infrastructure;
 /// </summary>
 public sealed class AclHttpClient(HttpClient http, AclOptions options) : IAclClient
 {
-    public async Task<Uri> OpenZaakAsync(string bsn, CancellationToken ct = default)
+    public async Task<Uri> OpenZaakAsync(string bsn, string reference, CancellationToken ct = default)
     {
         using var response = await http.PostAsJsonAsync(
-            new Uri(options.BaseUrl, "zaken"), new OpenZaakRequest(bsn), ct);
+            new Uri(options.BaseUrl, "zaken"), new OpenZaakRequest(bsn, reference), ct);
         response.EnsureSuccessStatusCode();
 
         var opened = await response.Content.ReadFromJsonAsync<OpenZaakResponse>(ct)
@@ -31,7 +31,9 @@ public sealed class AclHttpClient(HttpClient http, AclOptions options) : IAclCli
         response.EnsureSuccessStatusCode();
     }
 
-    private sealed record OpenZaakRequest([property: JsonPropertyName("bsn")] string Bsn);
+    private sealed record OpenZaakRequest(
+        [property: JsonPropertyName("bsn")] string Bsn,
+        [property: JsonPropertyName("reference")] string Reference);
 
     private sealed record OpenZaakResponse([property: JsonPropertyName("zaakUrl")] string ZaakUrl);
 

services/domain/Big.Infrastructure/FlowableWorkflowClient.cs

@@ -15,12 +15,14 @@ namespace Big.Infrastructure;
 /// The REST contract here is the one verified against a live flowable-rest engine (ADR-0009).
 /// </summary>
 public sealed class FlowableWorkflowClient(HttpClient http, FlowableOptions options)
-    : IWorkflowClient, IExternalWorkerClient
+    : IWorkflowClient, IExternalWorkerClient, IUserTaskClient
 {
     private const string Topic = "OpenZaakAanmaken";
     private const string ProcessDefinitionKey = "registratie";
+    private const string BeoordelenTaskKey = "Beoordelen";
     private const string RegistrationIdVariable = "registrationId";
     private const string ZaakUrlVariable = "zaakUrl";
+    private const string BesluitVariable = "besluit";
 
     public async Task<string> StartRegistrationProcessAsync(RegistrationId registrationId, CancellationToken ct = default)
     {
@@ -55,6 +57,34 @@ public sealed class FlowableWorkflowClient(HttpClient http, FlowableOptions opti
         response.EnsureSuccessStatusCode();
     }
 
+    public async Task<IReadOnlyList<BeoordelingTask>> GetOpenBeoordelingenAsync(CancellationToken ct = default)
+    {
+        var request = new TaskQueryRequest(ProcessDefinitionKey, BeoordelenTaskKey, IncludeProcessVariables: true);
+
+        var page = await PostAsync<TaskQueryRequest, TaskQueryResult>(
+            "service/query/tasks", request, ct);
+
+        var tasks = page?.Data ?? [];
+        return [.. tasks.Select(t => new BeoordelingTask(t.Id, RegistrationId.Parse(t.RegistrationId())))];
+    }
+
+    public async Task ClaimAsync(string taskId, string behandelaar, CancellationToken ct = default)
+    {
+        using var response = await SendAsync(
+            $"service/runtime/tasks/{taskId}", new ClaimTaskRequest("claim", behandelaar), ct);
+        response.EnsureSuccessStatusCode();
+    }
+
+    public async Task CompleteBeoordelingAsync(string taskId, BeoordelingsBesluit besluit, CancellationToken ct = default)
+    {
+        var request = new CompleteTaskRequest(
+            "complete",
+            [new Variable(BesluitVariable, "string", besluit.ToString().ToLowerInvariant())]);
+
+        using var response = await SendAsync($"service/runtime/tasks/{taskId}", request, ct);
+        response.EnsureSuccessStatusCode();
+    }
+
     private async Task<TResponse?> PostAsync<TRequest, TResponse>(string path, TRequest body, CancellationToken ct)
     {
         using var response = await SendAsync(path, body, ct);
@@ -89,6 +119,34 @@ public sealed class FlowableWorkflowClient(HttpClient http, FlowableOptions opti
         [property: JsonPropertyName("workerId")] string WorkerId,
         [property: JsonPropertyName("variables")] IReadOnlyList<Variable> Variables);
 
+    private sealed record TaskQueryRequest(
+        [property: JsonPropertyName("processDefinitionKey")] string ProcessDefinitionKey,
+        [property: JsonPropertyName("taskDefinitionKey")] string TaskDefinitionKey,
+        [property: JsonPropertyName("includeProcessVariables")] bool IncludeProcessVariables);
+
+    private sealed record ClaimTaskRequest(
+        [property: JsonPropertyName("action")] string Action,
+        [property: JsonPropertyName("assignee")] string Assignee);
+
+    private sealed record CompleteTaskRequest(
+        [property: JsonPropertyName("action")] string Action,
+        [property: JsonPropertyName("variables")] IReadOnlyList<Variable> Variables);
+
+    private sealed record TaskQueryResult(
+        [property: JsonPropertyName("data")] IReadOnlyList<UserTaskDto>? Data);
+
+    private sealed record UserTaskDto(
+        [property: JsonPropertyName("id")] string Id,
+        // Flowable's task-query returns the (included) process variables under "variables", not
+        // "processVariables"; the request opts in via includeProcessVariables.
+        [property: JsonPropertyName("variables")] IReadOnlyList<Variable>? Variables)
+    {
+        /// <summary>The registration id this task carries as a process variable.</summary>
+        public string RegistrationId() =>
+            Variables?.SingleOrDefault(v => v.Name == "registrationId")?.Value
+            ?? throw new InvalidOperationException($"Beoordelen task {Id} carries no registrationId variable.");
+    }
+
     private sealed record Variable(
         [property: JsonPropertyName("name")] string Name,
         [property: JsonPropertyName("type")] string Type,

services/domain/Big.Tests/AclHttpClientTests.cs

@@ -15,12 +15,13 @@ public class AclHttpClientTests
         var client = Client(capture.Responds(HttpStatusCode.OK,
             """{"zaakUrl":"http://openzaak/zaken/api/v1/zaken/abc"}"""));
 
-        var url = await client.OpenZaakAsync("123456782");
+        var url = await client.OpenZaakAsync("123456782", "reg-42");
 
         Assert.Equal("http://openzaak/zaken/api/v1/zaken/abc", url.ToString());
         Assert.Equal(HttpMethod.Post, capture.Seen!.Method);
         Assert.Equal("http://acl/zaken", capture.Seen.RequestUri!.ToString());
         Assert.Contains("\"bsn\":\"123456782\"", capture.Body);
+        Assert.Contains("\"reference\":\"reg-42\"", capture.Body);
     }
 
     [Fact]
@@ -29,7 +30,7 @@ public class AclHttpClientTests
         var capture = new RequestCapture();
         var client = Client(capture.Responds(HttpStatusCode.BadGateway));
 
-        await Assert.ThrowsAsync<HttpRequestException>(() => client.OpenZaakAsync("123456782"));
+        await Assert.ThrowsAsync<HttpRequestException>(() => client.OpenZaakAsync("123456782", "reg-1"));
     }
 
     [Fact]
@@ -38,7 +39,7 @@ public class AclHttpClientTests
         var capture = new RequestCapture();
         var client = Client(capture.Responds(HttpStatusCode.OK, "null"));
 
-        var ex = await Assert.ThrowsAsync<InvalidOperationException>(() => client.OpenZaakAsync("123456782"));
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(() => client.OpenZaakAsync("123456782", "reg-1"));
         Assert.Contains("empty", ex.Message, StringComparison.OrdinalIgnoreCase);
     }
 
@@ -64,4 +65,14 @@ public class AclHttpClientTests
         await Assert.ThrowsAsync<HttpRequestException>(
             () => client.ApproveZaakAsync(new Uri("http://openzaak/zaken/api/v1/zaken/abc")));
     }
+
+    [Fact]
+    public async Task Approve_rejects_a_null_zaak_url_without_sending_a_request()
+    {
+        var capture = new RequestCapture();
+        var client = Client(capture.Responds(HttpStatusCode.NoContent));
+
+        await Assert.ThrowsAsync<ArgumentNullException>(() => client.ApproveZaakAsync(null!));
+        Assert.Null(capture.Seen);
+    }
 }

services/domain/Big.Tests/ApproveRegistrationTests.cs

@@ -27,6 +27,19 @@ public class ApproveRegistrationTests
         Assert.Equal(RegistrationStatus.Ingeschreven, saved!.Status);
         Assert.Equal(FakeAclClient.DefaultZaakUrl, acl.ApprovedZaakUrl);
         Assert.Equal(1, acl.ApproveCallCount);
+        // The approved aggregate is persisted (not just mutated in memory).
+        Assert.Equal(1, store.SaveCount);
+    }
+
+    [Fact]
+    public async Task Rejects_a_null_command_without_touching_the_store_or_acl()
+    {
+        var store = new FakeRegistrationStore();
+        var acl = new FakeAclClient();
+        var handler = new ApproveRegistration(store, acl);
+
+        await Assert.ThrowsAsync<ArgumentNullException>(() => handler.HandleAsync(null!));
+        Assert.Equal(0, acl.ApproveCallCount);
     }
 
     [Fact]
@@ -36,8 +49,9 @@ public class ApproveRegistrationTests
         var acl = new FakeAclClient();
         var handler = new ApproveRegistration(store, acl);
 
-        await Assert.ThrowsAsync<InvalidOperationException>(
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(
             () => handler.HandleAsync(new ApproveRegistrationCommand(RegistrationId.New())));
+        Assert.Contains("No registration", ex.Message);
         Assert.Equal(0, acl.ApproveCallCount);
     }
 
@@ -50,8 +64,9 @@ public class ApproveRegistrationTests
         store.Seed(registration);
         var handler = new ApproveRegistration(store, acl);
 
-        await Assert.ThrowsAsync<InvalidOperationException>(
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(
             () => handler.HandleAsync(new ApproveRegistrationCommand(registration.Id)));
+        Assert.Contains("no zaak", ex.Message);
         Assert.Equal(0, acl.ApproveCallCount);
     }
 

services/domain/Big.Tests/BeoordeelRegistratieTests.cs

@@ -0,0 +1,168 @@
+using Big.Application;
+using Big.Domain;
+
+namespace Big.Tests;
+
+/// <summary>
+/// The beoordeling use case (S-12): a behandelaar's decision on a registration. Goedkeuren sets the
+/// zaak's final status via the ACL (§8.1) and marks the aggregate INGESCHREVEN; Afwijzen marks it
+/// AFGEWEZEN. Either way the decision also completes the Flowable Beoordelen task (found by
+/// registrationId) so the process advances. All idempotent — a repeated decision is a no-op.
+/// </summary>
+public class BeoordeelRegistratieTests
+{
+    private static Registration WithZaak(string bsn = "123456782")
+    {
+        var registration = Registration.Submit(bsn);
+        registration.AttachZaak(FakeAclClient.DefaultZaakUrl);
+        return registration;
+    }
+
+    private static FakeUserTaskClient TaskFor(Registration registration) =>
+        new([new BeoordelingTask("task-1", registration.Id)]);
+
+    [Fact]
+    public async Task Goedkeuren_sets_the_zaak_status_via_the_acl_and_marks_the_registration_ingeschreven()
+    {
+        var store = new FakeRegistrationStore();
+        var acl = new FakeAclClient();
+        var registration = WithZaak();
+        store.Seed(registration);
+        var tasks = TaskFor(registration);
+        var handler = new BeoordeelRegistratie(store, acl, tasks);
+
+        await handler.HandleAsync(new BeoordeelRegistratieCommand(registration.Id, BeoordelingsBesluit.Goedkeuren));
+
+        var saved = await store.GetAsync(registration.Id);
+        Assert.Equal(RegistrationStatus.Ingeschreven, saved!.Status);
+        Assert.Equal(FakeAclClient.DefaultZaakUrl, acl.ApprovedZaakUrl);
+        Assert.Equal(1, acl.ApproveCallCount);
+        Assert.Equal(1, store.SaveCount);
+        // The behandelaar's decision advances the workflow: the Beoordelen task is completed.
+        Assert.Equal(("task-1", BeoordelingsBesluit.Goedkeuren), tasks.Completed);
+    }
+
+    [Fact]
+    public async Task Afwijzen_marks_the_registration_afgewezen_without_calling_the_acl()
+    {
+        var store = new FakeRegistrationStore();
+        var acl = new FakeAclClient();
+        var registration = WithZaak();
+        store.Seed(registration);
+        var tasks = TaskFor(registration);
+        var handler = new BeoordeelRegistratie(store, acl, tasks);
+
+        await handler.HandleAsync(new BeoordeelRegistratieCommand(registration.Id, BeoordelingsBesluit.Afwijzen));
+
+        var saved = await store.GetAsync(registration.Id);
+        Assert.Equal(RegistrationStatus.Afgewezen, saved!.Status);
+        Assert.Equal(0, acl.ApproveCallCount);
+        Assert.Equal(1, store.SaveCount);
+        Assert.Equal(("task-1", BeoordelingsBesluit.Afwijzen), tasks.Completed);
+    }
+
+    [Fact]
+    public async Task Goedkeuren_an_in_behandeling_registration_marks_it_ingeschreven()
+    {
+        var store = new FakeRegistrationStore();
+        var acl = new FakeAclClient();
+        var registration = WithZaak();
+        registration.TakeIntoBehandeling();
+        store.Seed(registration);
+        var handler = new BeoordeelRegistratie(store, acl, TaskFor(registration));
+
+        await handler.HandleAsync(new BeoordeelRegistratieCommand(registration.Id, BeoordelingsBesluit.Goedkeuren));
+
+        Assert.Equal(RegistrationStatus.Ingeschreven, (await store.GetAsync(registration.Id))!.Status);
+    }
+
+    [Fact]
+    public async Task Rejects_a_null_command_without_touching_the_store_or_acl()
+    {
+        var store = new FakeRegistrationStore();
+        var acl = new FakeAclClient();
+        var handler = new BeoordeelRegistratie(store, acl, new FakeUserTaskClient([]));
+
+        await Assert.ThrowsAsync<ArgumentNullException>(() => handler.HandleAsync(null!));
+        Assert.Equal(0, acl.ApproveCallCount);
+        Assert.Equal(0, store.SaveCount);
+    }
+
+    [Fact]
+    public async Task Deciding_an_unknown_registration_throws_and_does_not_call_the_acl()
+    {
+        var store = new FakeRegistrationStore();
+        var acl = new FakeAclClient();
+        var handler = new BeoordeelRegistratie(store, acl, new FakeUserTaskClient([]));
+
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(() =>
+            handler.HandleAsync(new BeoordeelRegistratieCommand(RegistrationId.New(), BeoordelingsBesluit.Goedkeuren)));
+        Assert.Contains("No registration", ex.Message);
+        Assert.Equal(0, acl.ApproveCallCount);
+    }
+
+    [Fact]
+    public async Task Goedkeuren_before_the_zaak_is_opened_throws_without_calling_the_acl()
+    {
+        var store = new FakeRegistrationStore();
+        var acl = new FakeAclClient();
+        var registration = Registration.Submit("123456782"); // no zaak yet
+        store.Seed(registration);
+        var handler = new BeoordeelRegistratie(store, acl, TaskFor(registration));
+
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(() =>
+            handler.HandleAsync(new BeoordeelRegistratieCommand(registration.Id, BeoordelingsBesluit.Goedkeuren)));
+        Assert.Contains("no zaak", ex.Message);
+        Assert.Equal(0, acl.ApproveCallCount);
+    }
+
+    [Fact]
+    public async Task Re_goedkeuren_an_already_ingeschreven_registration_is_idempotent()
+    {
+        var store = new FakeRegistrationStore();
+        var acl = new FakeAclClient();
+        var registration = WithZaak();
+        store.Seed(registration);
+        var handler = new BeoordeelRegistratie(store, acl, TaskFor(registration));
+
+        await handler.HandleAsync(new BeoordeelRegistratieCommand(registration.Id, BeoordelingsBesluit.Goedkeuren));
+        await handler.HandleAsync(new BeoordeelRegistratieCommand(registration.Id, BeoordelingsBesluit.Goedkeuren));
+
+        Assert.Equal(1, acl.ApproveCallCount);
+        Assert.Equal(RegistrationStatus.Ingeschreven, (await store.GetAsync(registration.Id))!.Status);
+    }
+
+    [Fact]
+    public async Task Re_afwijzen_an_already_afgewezen_registration_is_idempotent()
+    {
+        var store = new FakeRegistrationStore();
+        var acl = new FakeAclClient();
+        var registration = WithZaak();
+        store.Seed(registration);
+        var handler = new BeoordeelRegistratie(store, acl, TaskFor(registration));
+
+        await handler.HandleAsync(new BeoordeelRegistratieCommand(registration.Id, BeoordelingsBesluit.Afwijzen));
+        await handler.HandleAsync(new BeoordeelRegistratieCommand(registration.Id, BeoordelingsBesluit.Afwijzen));
+
+        Assert.Equal(1, store.SaveCount);
+        Assert.Equal(RegistrationStatus.Afgewezen, (await store.GetAsync(registration.Id))!.Status);
+    }
+
+    [Fact]
+    public async Task Deciding_completes_no_task_when_none_is_open_for_the_registration()
+    {
+        // The task may already be gone (redelivery / manual completion). The decision still applies
+        // and simply completes nothing rather than failing.
+        var store = new FakeRegistrationStore();
+        var acl = new FakeAclClient();
+        var registration = WithZaak();
+        store.Seed(registration);
+        var tasks = new FakeUserTaskClient([]); // no open task for this registration
+        var handler = new BeoordeelRegistratie(store, acl, tasks);
+
+        await handler.HandleAsync(new BeoordeelRegistratieCommand(registration.Id, BeoordelingsBesluit.Goedkeuren));
+
+        Assert.Equal(RegistrationStatus.Ingeschreven, (await store.GetAsync(registration.Id))!.Status);
+        Assert.Null(tasks.Completed);
+    }
+}

services/domain/Big.Tests/Fakes.cs

@@ -41,6 +41,29 @@ internal sealed class FakeWorkflowClient(string processInstanceId = "proc-1", Ac
     }
 }
 
+/// <summary>A fake user-task client for the werkbak/decision use cases: returns a scripted set of
+/// open beoordeling tasks and records claim/complete calls.</summary>
+internal sealed class FakeUserTaskClient(IReadOnlyList<BeoordelingTask> open) : IUserTaskClient
+{
+    public (string TaskId, string Behandelaar)? Claimed { get; private set; }
+    public (string TaskId, BeoordelingsBesluit Besluit)? Completed { get; private set; }
+
+    public Task<IReadOnlyList<BeoordelingTask>> GetOpenBeoordelingenAsync(CancellationToken ct = default)
+        => Task.FromResult(open);
+
+    public Task ClaimAsync(string taskId, string behandelaar, CancellationToken ct = default)
+    {
+        Claimed = (taskId, behandelaar);
+        return Task.CompletedTask;
+    }
+
+    public Task CompleteBeoordelingAsync(string taskId, BeoordelingsBesluit besluit, CancellationToken ct = default)
+    {
+        Completed = (taskId, besluit);
+        return Task.CompletedTask;
+    }
+}
+
 /// <summary>A fake ACL client that records the bsn it was asked to open a zaak for and returns a
 /// fixed zaak URL.</summary>
 internal sealed class FakeAclClient(Uri? zaakUrl = null) : IAclClient
@@ -50,15 +73,17 @@ internal sealed class FakeAclClient(Uri? zaakUrl = null) : IAclClient
     private readonly Uri _zaakUrl = zaakUrl ?? DefaultZaakUrl;
 
     public string? OpenedForBsn { get; private set; }
+    public string? OpenedWithReference { get; private set; }
     public int CallCount { get; private set; }
 
     public Uri? ApprovedZaakUrl { get; private set; }
     public int ApproveCallCount { get; private set; }
 
-    public Task<Uri> OpenZaakAsync(string bsn, CancellationToken ct = default)
+    public Task<Uri> OpenZaakAsync(string bsn, string reference, CancellationToken ct = default)
     {
         CallCount++;
         OpenedForBsn = bsn;
+        OpenedWithReference = reference;
         return Task.FromResult(_zaakUrl);
     }
 

services/domain/Big.Tests/FlowableWorkflowClientTests.cs

@@ -1,5 +1,6 @@
 using System.Net;
 using System.Text;
+using Big.Application;
 using Big.Domain;
 using Big.Infrastructure;
 
@@ -127,6 +128,17 @@ public class FlowableWorkflowClientTests
             () => client.StartRegistrationProcessAsync(RegistrationId.New()));
     }
 
+    [Fact]
+    public async Task Start_throws_when_flowable_returns_an_empty_body()
+    {
+        var capture = new RequestCapture();
+        var client = Client(capture.Responds(HttpStatusCode.Created, "null"));
+
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(
+            () => client.StartRegistrationProcessAsync(RegistrationId.New()));
+        Assert.Contains("empty process-instance", ex.Message);
+    }
+
     [Fact]
     public async Task Complete_throws_when_flowable_rejects_the_request()
     {
@@ -136,4 +148,107 @@ public class FlowableWorkflowClientTests
         await Assert.ThrowsAsync<HttpRequestException>(
             () => client.CompleteOpenZaakJobAsync("job-1", new Uri("http://openzaak/zaken/api/v1/zaken/abc")));
     }
+
+    // ── S-12b: behandelaar user tasks (werkbak / claim / complete) ────────────────────────────────
+
+    [Fact]
+    public async Task Open_beoordelingen_queries_beoordelen_tasks_with_their_registration_id()
+    {
+        var rid = RegistrationId.New();
+        var capture = new RequestCapture();
+        var client = Client(capture.Responds(HttpStatusCode.OK,
+            $$"""
+            {"data":[{"id":"task-1","variables":[{"name":"registrationId","type":"string","value":"{{rid}}"}]}],"total":1}
+            """));
+
+        var tasks = await client.GetOpenBeoordelingenAsync();
+
+        var task = Assert.Single(tasks);
+        Assert.Equal("task-1", task.TaskId);
+        Assert.Equal(rid, task.RegistrationId);
+        Assert.Equal(HttpMethod.Post, capture.Seen!.Method);
+        Assert.Equal("http://flowable/flowable-rest/service/query/tasks",
+            capture.Seen.RequestUri!.ToString());
+        Assert.Equal("rest-admin:test", DecodeBasic(capture.Seen));
+        Assert.Contains("\"processDefinitionKey\":\"registratie\"", capture.Body);
+        Assert.Contains("\"taskDefinitionKey\":\"Beoordelen\"", capture.Body);
+        Assert.Contains("\"includeProcessVariables\":true", capture.Body);
+    }
+
+    [Theory]
+    [InlineData("""{"data":[],"total":0}""")]
+    [InlineData("""{"data":null,"total":0}""")]
+    public async Task Open_beoordelingen_is_empty_when_no_tasks_are_waiting(string body)
+    {
+        var capture = new RequestCapture();
+        var client = Client(capture.Responds(HttpStatusCode.OK, body));
+
+        Assert.Empty(await client.GetOpenBeoordelingenAsync());
+        Assert.NotNull(capture.Seen);
+    }
+
+    [Fact]
+    public async Task Open_beoordelingen_throws_when_a_task_carries_no_registration_id()
+    {
+        var capture = new RequestCapture();
+        var client = Client(capture.Responds(HttpStatusCode.OK,
+            """{"data":[{"id":"task-1","variables":[]}],"total":1}"""));
+
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(() => client.GetOpenBeoordelingenAsync());
+        Assert.Contains("task-1", ex.Message);
+        Assert.Contains("registrationId", ex.Message);
+    }
+
+    [Fact]
+    public async Task Claim_assigns_the_task_to_the_behandelaar()
+    {
+        var capture = new RequestCapture();
+        var client = Client(capture.Responds(HttpStatusCode.OK));
+
+        await client.ClaimAsync("task-1", "merel-behandelaar");
+
+        Assert.Equal(HttpMethod.Post, capture.Seen!.Method);
+        Assert.Equal("http://flowable/flowable-rest/service/runtime/tasks/task-1",
+            capture.Seen.RequestUri!.ToString());
+        Assert.Contains("\"action\":\"claim\"", capture.Body);
+        Assert.Contains("\"assignee\":\"merel-behandelaar\"", capture.Body);
+    }
+
+    [Fact]
+    public async Task Claim_throws_when_flowable_rejects_the_request()
+    {
+        var capture = new RequestCapture();
+        var client = Client(capture.Responds(HttpStatusCode.Conflict));
+
+        await Assert.ThrowsAsync<HttpRequestException>(() => client.ClaimAsync("task-1", "merel-behandelaar"));
+    }
+
+    [Theory]
+    [InlineData(BeoordelingsBesluit.Goedkeuren, "goedkeuren")]
+    [InlineData(BeoordelingsBesluit.Afwijzen, "afwijzen")]
+    public async Task Complete_posts_the_besluit_variable_to_the_task(BeoordelingsBesluit besluit, string expected)
+    {
+        var capture = new RequestCapture();
+        var client = Client(capture.Responds(HttpStatusCode.OK));
+
+        await client.CompleteBeoordelingAsync("task-1", besluit);
+
+        Assert.Equal(HttpMethod.Post, capture.Seen!.Method);
+        Assert.Equal("http://flowable/flowable-rest/service/runtime/tasks/task-1",
+            capture.Seen.RequestUri!.ToString());
+        Assert.Contains("\"action\":\"complete\"", capture.Body);
+        Assert.Contains("\"name\":\"besluit\"", capture.Body);
+        Assert.Contains("\"type\":\"string\"", capture.Body);
+        Assert.Contains($"\"value\":\"{expected}\"", capture.Body);
+    }
+
+    [Fact]
+    public async Task Complete_beoordeling_throws_when_flowable_rejects_the_request()
+    {
+        var capture = new RequestCapture();
+        var client = Client(capture.Responds(HttpStatusCode.InternalServerError));
+
+        await Assert.ThrowsAsync<HttpRequestException>(
+            () => client.CompleteBeoordelingAsync("task-1", BeoordelingsBesluit.Goedkeuren));
+    }
 }

services/domain/Big.Tests/OpenZaakWorkerTests.cs

@@ -25,6 +25,9 @@ public class OpenZaakWorkerTests
 
         Assert.Equal(FakeAclClient.DefaultZaakUrl, zaakUrl);
         Assert.Equal("123456782", acl.OpenedForBsn);
+        // The registration's own id is handed to the ACL as the zaak reference (identificatie),
+        // so the openbaar register can show the reference the zorgprofessional received (#78).
+        Assert.Equal(registration.Id.ToString(), acl.OpenedWithReference);
         var saved = await store.GetAsync(registration.Id);
         Assert.Equal(FakeAclClient.DefaultZaakUrl, saved!.ZaakUrl);
         Assert.Equal(1, store.SaveCount);

services/domain/Big.Tests/RegistrationTests.cs

@@ -117,7 +117,104 @@ public class RegistrationTests
         registration.AttachZaak(new Uri("http://openzaak/zaken/api/v1/zaken/abc"));
         registration.Approve();
 
-        Assert.Throws<InvalidOperationException>(() => registration.Approve());
+        var ex = Assert.Throws<InvalidOperationException>(() => registration.Approve());
+        Assert.Contains("only an INGEDIEND", ex.Message);
         Assert.Equal(RegistrationStatus.Ingeschreven, registration.Status);
     }
+
+    [Fact]
+    public void Taking_a_registration_into_behandeling_moves_it_to_in_behandeling()
+    {
+        var registration = Registration.Submit("123456782");
+
+        registration.TakeIntoBehandeling();
+
+        Assert.Equal(RegistrationStatus.InBehandeling, registration.Status);
+    }
+
+    [Fact]
+    public void Re_taking_an_in_behandeling_registration_is_idempotent()
+    {
+        var registration = Registration.Submit("123456782");
+        registration.TakeIntoBehandeling();
+
+        registration.TakeIntoBehandeling();
+
+        Assert.Equal(RegistrationStatus.InBehandeling, registration.Status);
+    }
+
+    [Fact]
+    public void Taking_a_decided_registration_into_behandeling_is_rejected()
+    {
+        var registration = Registration.Submit("123456782");
+        registration.AttachZaak(new Uri("http://openzaak/zaken/api/v1/zaken/abc"));
+        registration.Approve();
+
+        var ex = Assert.Throws<InvalidOperationException>(() => registration.TakeIntoBehandeling());
+        Assert.Contains("only an INGEDIEND", ex.Message);
+        Assert.Equal(RegistrationStatus.Ingeschreven, registration.Status);
+    }
+
+    [Fact]
+    public void Approving_an_in_behandeling_registration_with_a_zaak_sets_it_ingeschreven()
+    {
+        var registration = Registration.Submit("123456782");
+        registration.AttachZaak(new Uri("http://openzaak/zaken/api/v1/zaken/abc"));
+        registration.TakeIntoBehandeling();
+
+        registration.Approve();
+
+        Assert.Equal(RegistrationStatus.Ingeschreven, registration.Status);
+    }
+
+    [Fact]
+    public void Rejecting_a_registration_sets_it_afgewezen()
+    {
+        var registration = Registration.Submit("123456782");
+
+        registration.Reject();
+
+        Assert.Equal(RegistrationStatus.Afgewezen, registration.Status);
+    }
+
+    [Fact]
+    public void Rejecting_needs_no_zaak()
+    {
+        // A registration can be turned down before its zaak is ever opened, so Reject must not require one.
+        var registration = Registration.Submit("123456782");
+
+        registration.Reject();
+
+        Assert.Equal(RegistrationStatus.Afgewezen, registration.Status);
+        Assert.Null(registration.ZaakUrl);
+    }
+
+    [Fact]
+    public void Rejecting_an_in_behandeling_registration_sets_it_afgewezen()
+    {
+        var registration = Registration.Submit("123456782");
+        registration.TakeIntoBehandeling();
+
+        registration.Reject();
+
+        Assert.Equal(RegistrationStatus.Afgewezen, registration.Status);
+    }
+
+    [Fact]
+    public void Deciding_an_already_decided_registration_is_rejected()
+    {
+        var registration = Registration.Submit("123456782");
+        registration.Reject();
+
+        var approveEx = Assert.Throws<InvalidOperationException>(() =>
+        {
+            registration.AttachZaak(new Uri("http://openzaak/zaken/api/v1/zaken/abc"));
+            registration.Approve();
+        });
+        Assert.Contains("IN_BEHANDELING", approveEx.Message);
+
+        var rejectEx = Assert.Throws<InvalidOperationException>(() => registration.Reject());
+        Assert.Contains("Afgewezen", rejectEx.Message);
+        Assert.Equal(RegistrationStatus.Afgewezen, registration.Status);
+    }
 }

services/domain/Big.Tests/WerkbakTests.cs

@@ -0,0 +1,49 @@
+using Big.Application;
+using Big.Domain;
+
+namespace Big.Tests;
+
+/// <summary>
+/// The werkbak query (S-12c): the behandelaar's list of registrations awaiting beoordeling. It reads
+/// the open Beoordelen tasks from the workflow engine (§8.2) and enriches each with its registration
+/// (bsn + status) from the store. A task whose registration is unknown is skipped defensively.
+/// </summary>
+public class WerkbakTests
+{
+    [Fact]
+    public async Task Lists_an_item_per_open_beoordeling_enriched_from_the_registration()
+    {
+        var store = new FakeRegistrationStore();
+        var registration = Registration.Submit("123456782");
+        registration.AttachZaak(FakeAclClient.DefaultZaakUrl);
+        registration.TakeIntoBehandeling();
+        store.Seed(registration);
+        var tasks = new FakeUserTaskClient([new BeoordelingTask("task-1", registration.Id)]);
+        var werkbak = new Werkbak(tasks, store);
+
+        var items = await werkbak.GetAsync();
+
+        var item = Assert.Single(items);
+        Assert.Equal(registration.Id.ToString(), item.RegistrationId);
+        Assert.Equal("123456782", item.Bsn);
+        Assert.Equal("InBehandeling", item.Status);
+    }
+
+    [Fact]
+    public async Task Is_empty_when_no_beoordelingen_are_open()
+    {
+        var werkbak = new Werkbak(new FakeUserTaskClient([]), new FakeRegistrationStore());
+
+        Assert.Empty(await werkbak.GetAsync());
+    }
+
+    [Fact]
+    public async Task Skips_a_task_whose_registration_is_unknown()
+    {
+        // Defensive: the werkbak never invents an item for a task the domain has no aggregate for.
+        var tasks = new FakeUserTaskClient([new BeoordelingTask("task-1", RegistrationId.New())]);
+        var werkbak = new Werkbak(tasks, new FakeRegistrationStore());
+
+        Assert.Empty(await werkbak.GetAsync());
+    }
+}

services/event-subscriber/EventSubscriber.Api/AclHttpClient.cs

@@ -0,0 +1,30 @@
+using System.Net.Http.Json;
+using System.Text.Json.Serialization;
+using EventSubscriber.Application;
+
+namespace EventSubscriber.Api;
+
+/// <summary>
+/// HTTP client to the ACL service. The subscriber enriches the projection with the zaak's reference
+/// (identificatie) by asking the ACL — the only code that may read ZGW (§8.1) — rather than reading
+/// OpenZaak itself (adr-proposal #78).
+/// </summary>
+public sealed class AclHttpClient(HttpClient http) : IAclClient
+{
+    public async Task<string> GetZaakReferenceAsync(Uri zaakUrl, CancellationToken ct = default)
+    {
+        ArgumentNullException.ThrowIfNull(zaakUrl);
+
+        using var response = await http.PostAsJsonAsync(
+            new Uri(http.BaseAddress!, "zaken/reference"), new ReferenceRequest(zaakUrl.ToString()), ct);
+        response.EnsureSuccessStatusCode();
+
+        var body = await response.Content.ReadFromJsonAsync<ReferenceResponse>(ct)
+            ?? throw new InvalidOperationException("The ACL returned an empty reference response.");
+        return body.Reference;
+    }
+
+    private sealed record ReferenceRequest([property: JsonPropertyName("zaakUrl")] string ZaakUrl);
+
+    private sealed record ReferenceResponse([property: JsonPropertyName("reference")] string Reference);
+}

services/event-subscriber/EventSubscriber.Api/Program.cs

@@ -11,9 +11,15 @@ var connectionString = builder.Configuration.GetConnectionString("Projection")
 // this value (ADR-0007), so the webhook enforces it.
 var webhookToken = builder.Configuration["EventSubscriber:Webhook:AuthToken"]
     ?? throw new InvalidOperationException("Missing configuration 'EventSubscriber:Webhook:AuthToken'");
+// The ACL is the only code that may read ZGW (§8.1); the subscriber enriches the projection with the
+// zaak reference through it (adr-proposal #78).
+var aclBaseUrl = builder.Configuration["Acl:BaseUrl"]
+    ?? throw new InvalidOperationException("Missing configuration 'Acl:BaseUrl'");
 
 builder.Services.AddProjectionReadModel(connectionString);
 builder.Services.AddProjectionWriteSide();
+builder.Services.AddHttpClient<EventSubscriber.Application.IAclClient, EventSubscriber.Api.AclHttpClient>(
+    c => c.BaseAddress = new Uri(aclBaseUrl));
 
 var app = builder.Build();
 

services/event-subscriber/EventSubscriber.Application/Notification.cs

@@ -24,10 +24,12 @@ public sealed record Notification(
     public bool IsZaakStatusSet =>
         Kanaal == "zaken" && Resource == "status" && Actie == "create";
 
-    /// <summary>The zaak UUID used as the projection key. For a status notification the resource URL is
+    /// <summary>The zaak URL this notification concerns — <c>hoofdObject</c> (the zaak) for a status
-    /// the status, so the zaak comes from <c>hoofdObject</c> (which, for a zaak-create, equals the
+    /// notification, else the resource URL (which, for a zaak-create, is the zaak).</summary>
-    /// resource URL) — see the NRC payload note.</summary>
+    public Uri ZaakUrl => HoofdObject ?? ResourceUrl;
-    public string ZaakId => (HoofdObject ?? ResourceUrl).Segments[^1].Trim('/');
+
+    /// <summary>The zaak UUID used as the projection key — the trailing segment of <see cref="ZaakUrl"/>.</summary>
+    public string ZaakId => ZaakUrl.Segments[^1].Trim('/');
 
     /// <summary>
     /// A deterministic dedup key. Open Notificaties carries no notification id and may

services/event-subscriber/EventSubscriber.Application/NotificationProjector.cs

@@ -5,17 +5,19 @@ namespace EventSubscriber.Application;
 /// out-of-order deliveries (CLAUDE.md §8.6): the notification log dedups, and the projection
 /// upsert is idempotent on the zaak id. Rebuilds the projection by replaying the log.
 /// </summary>
-public sealed class NotificationProjector(INotificationLog log, IProjectionStore store)
+public sealed class NotificationProjector(INotificationLog log, IProjectionStore store, IAclClient acl)
 {
     /// <summary>Handle one inbound notification. Reacts to a zaak being created (INGEDIEND) and a
-    /// status being set (INGESCHREVEN); ignores everything else.</summary>
+    /// status being set (INGESCHREVEN); ignores everything else. Enriches the row with the zaak's
+    /// reference via the ACL (§8.1) and records it so a rebuild needs no ZGW access (#78).</summary>
     public async Task HandleAsync(Notification notification, CancellationToken ct = default)
     {
         if (!notification.IsZaakCreated && !notification.IsZaakStatusSet)
             return;
 
+        var reference = await acl.GetZaakReferenceAsync(notification.ZaakUrl, ct);
         var recorded = new RecordedNotification(
-            notification.IdempotencyKey, notification.Actie, notification.ZaakId, notification.Resource);
+            notification.IdempotencyKey, notification.Actie, notification.ZaakId, notification.Resource, reference);
 
         // Atomic record-or-skip: a duplicate (or concurrent) delivery is recognised and dropped
         // before it touches the projection, so the projection stays a faithful derived artefact.
@@ -36,7 +38,8 @@ public sealed class NotificationProjector(INotificationLog log, IProjectionStore
     /// <summary>The projection row for an accepted notification: a status-set maps to INGESCHREVEN,
     /// a zaak-create to INGEDIEND. bsn/naam are deferred (ADR-0008).</summary>
     private static RegisterEntry ToEntry(RecordedNotification recorded)
-        => new(recorded.ZaakId, recorded.Resource == "status"
+        => new(
-            ? RegistrationStatus.Ingeschreven
+            recorded.ZaakId,
-            : RegistrationStatus.Ingediend);
+            recorded.Resource == "status" ? RegistrationStatus.Ingeschreven : RegistrationStatus.Ingediend,
+            Reference: recorded.Reference);
 }

services/event-subscriber/EventSubscriber.Application/Ports.cs

@@ -20,9 +20,20 @@ public interface INotificationLog
 }
 
 /// <summary>A notification that has been accepted, retaining what a rebuild needs to recompute its
-/// projection row — including the ZGW <c>resource</c>, which distinguishes a zaak-create (INGEDIEND)
+/// projection row — the ZGW <c>resource</c> (zaak-create → INGEDIEND vs status-set → INGESCHREVEN) and
-/// from a status-set (INGESCHREVEN) so a rebuild reproduces the right status.</summary>
+/// the zaak <c>reference</c> (identificatie), so a rebuild reproduces the row without re-reading ZGW (#78).</summary>
-public sealed record RecordedNotification(string Key, string Actie, string ZaakId, string Resource);
+public sealed record RecordedNotification(string Key, string Actie, string ZaakId, string Resource, string? Reference);
+
+/// <summary>
+/// Port to the Anti-Corruption Layer. The subscriber enriches the projection with the zaak's
+/// public-safe reference (its identificatie) by asking the ACL — the only code that may read ZGW
+/// (§8.1) — rather than reading OpenZaak itself (adr-proposal #78).
+/// </summary>
+public interface IAclClient
+{
+    /// <summary>The zaak's reference (identificatie) for the read projection.</summary>
+    Task<string> GetZaakReferenceAsync(Uri zaakUrl, CancellationToken ct = default);
+}
 
 /// <summary>The read projection store. Owned by the projection bounded context (ADR-0008); the
 /// subscriber writes to it and the projection-api reads it.</summary>

services/event-subscriber/EventSubscriber.Application/RegisterEntry.cs

@@ -9,6 +9,7 @@ namespace EventSubscriber.Application;
 public sealed record RegisterEntry(
     string Id,
     string Status,
+    string? Reference = null,
     string? Bsn = null,
     string? NaamPlaceholder = null);
 

services/event-subscriber/EventSubscriber.Tests/AclHttpClientTests.cs

@@ -0,0 +1,86 @@
+using System.Net;
+using System.Text;
+using EventSubscriber.Api;
+
+namespace EventSubscriber.Tests;
+
+/// <summary>
+/// Unit tests for the subscriber's ACL client, which reads a zaak's reference (identificatie) through
+/// the ACL — the only code allowed to talk to ZGW (§8.1, #78). Uses a scripted message handler so no
+/// real ACL is required.
+/// </summary>
+public class AclHttpClientTests
+{
+    private static AclHttpClient Client(StubHandler handler) =>
+        new(new HttpClient(handler) { BaseAddress = new Uri("http://acl/") });
+
+    [Fact]
+    public async Task Reads_a_zaak_reference_by_posting_the_zaak_url_and_returns_it()
+    {
+        var capture = new RequestCapture();
+        var client = Client(capture.Responds(HttpStatusCode.OK, """{"reference":"REG-42"}"""));
+
+        var reference = await client.GetZaakReferenceAsync(new Uri("http://openzaak/zaken/api/v1/zaken/abc"));
+
+        Assert.Equal("REG-42", reference);
+        Assert.Equal(HttpMethod.Post, capture.Seen!.Method);
+        Assert.Equal("http://acl/zaken/reference", capture.Seen.RequestUri!.ToString());
+        Assert.Contains("\"zaakUrl\":\"http://openzaak/zaken/api/v1/zaken/abc\"", capture.Body);
+    }
+
+    [Fact]
+    public async Task Throws_when_the_acl_rejects_the_request()
+    {
+        var capture = new RequestCapture();
+        var client = Client(capture.Responds(HttpStatusCode.BadGateway));
+
+        await Assert.ThrowsAsync<HttpRequestException>(
+            () => client.GetZaakReferenceAsync(new Uri("http://openzaak/zaken/api/v1/zaken/abc")));
+    }
+
+    [Fact]
+    public async Task Throws_when_the_acl_returns_an_empty_body()
+    {
+        var capture = new RequestCapture();
+        var client = Client(capture.Responds(HttpStatusCode.OK, "null"));
+
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(
+            () => client.GetZaakReferenceAsync(new Uri("http://openzaak/zaken/api/v1/zaken/abc")));
+        Assert.Contains("empty", ex.Message, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public async Task Rejects_a_null_zaak_url_without_sending_a_request()
+    {
+        var capture = new RequestCapture();
+        var client = Client(capture.Responds(HttpStatusCode.OK, """{"reference":"REG-1"}"""));
+
+        await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetZaakReferenceAsync(null!));
+        Assert.Null(capture.Seen);
+    }
+}
+
+/// <summary>A test double for <see cref="HttpMessageHandler"/> that records the last request and
+/// returns a scripted response — mirrors the ACL/domain gateway tests.</summary>
+internal sealed class StubHandler(Func<HttpRequestMessage, Task<HttpResponseMessage>> onSend) : HttpMessageHandler
+{
+    protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken ct)
+        => onSend(request);
+}
+
+/// <summary>Captures the request a client sent, including the (buffered) body.</summary>
+internal sealed class RequestCapture
+{
+    public HttpRequestMessage? Seen { get; private set; }
+    public string? Body { get; private set; }
+
+    public StubHandler Responds(HttpStatusCode status, string? json = null) => new(async req =>
+    {
+        Seen = req;
+        Body = req.Content is null ? null : await req.Content.ReadAsStringAsync();
+        var response = new HttpResponseMessage(status);
+        if (json is not null)
+            response.Content = new StringContent(json, Encoding.UTF8, "application/json");
+        return response;
+    });
+}

services/event-subscriber/EventSubscriber.Tests/EventSubscriber.Tests.csproj

@@ -19,6 +19,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <ProjectReference Include="..\EventSubscriber.Api\EventSubscriber.Api.csproj" />
     <ProjectReference Include="..\EventSubscriber.Application\EventSubscriber.Application.csproj" />
   </ItemGroup>
 

services/event-subscriber/EventSubscriber.Tests/InMemoryStores.cs

@@ -5,6 +5,19 @@ namespace EventSubscriber.Tests;
 /// <summary>In-memory stand-ins for the projection store and notification log, so the
 /// projector's behaviour is exercised without Postgres (hand-written stubs, the repo's
 /// convention — no mocking library).</summary>
+/// <summary>A fake ACL client that returns a fixed reference derived from the zaak, and records
+/// how many times it was called (to prove a rebuild does not re-read via the ACL).</summary>
+internal sealed class FakeAclClient : IAclClient
+{
+    public int CallCount { get; private set; }
+
+    public Task<string> GetZaakReferenceAsync(Uri zaakUrl, CancellationToken ct = default)
+    {
+        CallCount++;
+        return Task.FromResult("REG-" + zaakUrl.Segments[^1].Trim('/'));
+    }
+}
+
 internal sealed class InMemoryNotificationLog : INotificationLog
 {
     private readonly Dictionary<string, RecordedNotification> _byKey = [];

services/event-subscriber/EventSubscriber.Tests/NotificationProjectorTests.cs

@@ -12,8 +12,9 @@ public sealed class NotificationProjectorTests
 
     private readonly InMemoryNotificationLog _log = new();
     private readonly InMemoryProjectionStore _store = new();
+    private readonly FakeAclClient _acl = new();
 
-    private NotificationProjector Projector() => new(_log, _store);
+    private NotificationProjector Projector() => new(_log, _store, _acl);
 
     private static Notification ZaakCreated(string url = ZaakUrl)
         => new("zaken", "zaak", "create", new Uri(url));
@@ -30,6 +31,23 @@ public sealed class NotificationProjectorTests
         var entry = Assert.Single(await _store.AllAsync());
         Assert.Equal("11111111-1111-1111-1111-111111111111", entry.Id);
         Assert.Equal(RegistrationStatus.Ingediend, entry.Status);
+        // Enriched with the zaak's reference (identificatie), fetched via the ACL (#78).
+        Assert.Equal("REG-11111111-1111-1111-1111-111111111111", entry.Reference);
+    }
+
+    [Fact]
+    public async Task rebuild_reproduces_the_reference_without_re_reading_via_the_acl()
+    {
+        var projector = Projector();
+        await projector.HandleAsync(ZaakCreated());
+        var callsAfterProjection = _acl.CallCount;
+
+        await projector.RebuildAsync();
+
+        var entry = Assert.Single(await _store.AllAsync());
+        Assert.Equal("REG-11111111-1111-1111-1111-111111111111", entry.Reference);
+        // Rebuild replays the log (which stored the reference) — no extra ACL calls (#78, ADR-0008).
+        Assert.Equal(callsAfterProjection, _acl.CallCount);
     }
 
     [Fact]

services/projection-api/Projection.ReadModel/EfNotificationLog.cs

@@ -16,6 +16,7 @@ public sealed class EfNotificationLog(ProjectionDbContext db) : INotificationLog
             Actie = notification.Actie,
             ZaakId = notification.ZaakId,
             Resource = notification.Resource,
+            Reference = notification.Reference,
             ReceivedAt = DateTimeOffset.UtcNow,
         });
 
@@ -35,6 +36,6 @@ public sealed class EfNotificationLog(ProjectionDbContext db) : INotificationLog
     public async Task<IReadOnlyList<RecordedNotification>> AllAsync(CancellationToken ct = default)
         => await db.ProcessedNotifications
             .OrderBy(r => r.ReceivedAt)
-            .Select(r => new RecordedNotification(r.Key, r.Actie, r.ZaakId, r.Resource))
+            .Select(r => new RecordedNotification(r.Key, r.Actie, r.ZaakId, r.Resource, r.Reference))
             .ToListAsync(ct);
 }

services/projection-api/Projection.ReadModel/EfProjectionStore.cs

@@ -15,6 +15,7 @@ public sealed class EfProjectionStore(ProjectionDbContext db) : IProjectionStore
             {
                 Id = entry.Id,
                 Status = entry.Status,
+                Reference = entry.Reference,
                 Bsn = entry.Bsn,
                 NaamPlaceholder = entry.NaamPlaceholder,
             });
@@ -22,6 +23,7 @@ public sealed class EfProjectionStore(ProjectionDbContext db) : IProjectionStore
         else
         {
             row.Status = entry.Status;
+            row.Reference = entry.Reference;
             row.Bsn = entry.Bsn;
             row.NaamPlaceholder = entry.NaamPlaceholder;
         }
@@ -35,6 +37,6 @@ public sealed class EfProjectionStore(ProjectionDbContext db) : IProjectionStore
     public async Task<IReadOnlyList<RegisterEntry>> AllAsync(CancellationToken ct = default)
         => await db.RegisterEntries
             .OrderBy(r => r.Id)
-            .Select(r => new RegisterEntry(r.Id, r.Status, r.Bsn, r.NaamPlaceholder))
+            .Select(r => new RegisterEntry(r.Id, r.Status, Reference: r.Reference, Bsn: r.Bsn, NaamPlaceholder: r.NaamPlaceholder))
             .ToListAsync(ct);
 }

services/projection-api/Projection.ReadModel/Migrations/20260714101642_AddReferenceColumns.Designer.cs

@@ -0,0 +1,92 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+using Projection.ReadModel;
+
+#nullable disable
+
+namespace Projection.ReadModel.Migrations
+{
+    [DbContext(typeof(ProjectionDbContext))]
+    [Migration("20260714101642_AddReferenceColumns")]
+    partial class AddReferenceColumns
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "10.0.0")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
+
+            modelBuilder.Entity("Projection.ReadModel.ProcessedNotificationRow", b =>
+                {
+                    b.Property<string>("Key")
+                        .HasColumnType("text")
+                        .HasColumnName("key");
+
+                    b.Property<string>("Actie")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("actie");
+
+                    b.Property<DateTimeOffset>("ReceivedAt")
+                        .HasColumnType("timestamp with time zone")
+                        .HasColumnName("received_at");
+
+                    b.Property<string>("Reference")
+                        .HasColumnType("text")
+                        .HasColumnName("reference");
+
+                    b.Property<string>("Resource")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("resource");
+
+                    b.Property<string>("ZaakId")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("zaak_id");
+
+                    b.HasKey("Key");
+
+                    b.ToTable("processed_notifications", (string)null);
+                });
+
+            modelBuilder.Entity("Projection.ReadModel.RegisterEntryRow", b =>
+                {
+                    b.Property<string>("Id")
+                        .HasColumnType("text")
+                        .HasColumnName("id");
+
+                    b.Property<string>("Bsn")
+                        .HasColumnType("text")
+                        .HasColumnName("bsn");
+
+                    b.Property<string>("NaamPlaceholder")
+                        .HasColumnType("text")
+                        .HasColumnName("naam_placeholder");
+
+                    b.Property<string>("Reference")
+                        .HasColumnType("text")
+                        .HasColumnName("reference");
+
+                    b.Property<string>("Status")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("status");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("register_projection", (string)null);
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

services/projection-api/Projection.ReadModel/Migrations/20260714101642_AddReferenceColumns.cs

@@ -0,0 +1,38 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Projection.ReadModel.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddReferenceColumns : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "reference",
+                table: "register_projection",
+                type: "text",
+                nullable: true);
+
+            migrationBuilder.AddColumn<string>(
+                name: "reference",
+                table: "processed_notifications",
+                type: "text",
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "reference",
+                table: "register_projection");
+
+            migrationBuilder.DropColumn(
+                name: "reference",
+                table: "processed_notifications");
+        }
+    }
+}

services/projection-api/Projection.ReadModel/Migrations/ProjectionDbContextModelSnapshot.cs

@@ -37,6 +37,10 @@ namespace Projection.ReadModel.Migrations
                         .HasColumnType("timestamp with time zone")
                         .HasColumnName("received_at");
 
+                    b.Property<string>("Reference")
+                        .HasColumnType("text")
+                        .HasColumnName("reference");
+
                     b.Property<string>("Resource")
                         .IsRequired()
                         .HasColumnType("text")
@@ -66,6 +70,10 @@ namespace Projection.ReadModel.Migrations
                         .HasColumnType("text")
                         .HasColumnName("naam_placeholder");
 
+                    b.Property<string>("Reference")
+                        .HasColumnType("text")
+                        .HasColumnName("reference");
+
                     b.Property<string>("Status")
                         .IsRequired()
                         .HasColumnType("text")

services/projection-api/Projection.ReadModel/ProjectionDbContext.cs

@@ -24,6 +24,7 @@ public sealed class ProjectionDbContext(DbContextOptions<ProjectionDbContext> op
             e.HasKey(r => r.Id);
             e.Property(r => r.Id).HasColumnName("id");
             e.Property(r => r.Status).HasColumnName("status").IsRequired();
+            e.Property(r => r.Reference).HasColumnName("reference");
             e.Property(r => r.Bsn).HasColumnName("bsn");
             e.Property(r => r.NaamPlaceholder).HasColumnName("naam_placeholder");
         });
@@ -36,6 +37,7 @@ public sealed class ProjectionDbContext(DbContextOptions<ProjectionDbContext> op
             e.Property(r => r.Actie).HasColumnName("actie").IsRequired();
             e.Property(r => r.ZaakId).HasColumnName("zaak_id").IsRequired();
             e.Property(r => r.Resource).HasColumnName("resource").IsRequired();
+            e.Property(r => r.Reference).HasColumnName("reference");
             e.Property(r => r.ReceivedAt).HasColumnName("received_at");
         });
     }
@@ -46,6 +48,10 @@ public sealed class RegisterEntryRow
 {
     public required string Id { get; set; }
     public required string Status { get; set; }
+
+    /// <summary>The citizen-facing reference (the zaak's identificatie) — matches the submit confirmation (#78).</summary>
+    public string? Reference { get; set; }
+
     public string? Bsn { get; set; }
     public string? NaamPlaceholder { get; set; }
 }
@@ -61,5 +67,8 @@ public sealed class ProcessedNotificationRow
     /// the right status without reading OpenZaak (S-09b).</summary>
     public required string Resource { get; set; }
 
+    /// <summary>The zaak reference (identificatie), retained so a rebuild reprojects it without the ACL (#78).</summary>
+    public string? Reference { get; set; }
+
     public DateTimeOffset ReceivedAt { get; set; }
 }

services/projection-api/Projection.ReadModel/ServiceCollectionExtensions.cs

@@ -19,12 +19,46 @@ public static class ServiceCollectionExtensions
         return services;
     }
 
+    // A fixed application-scoped key for the migration advisory lock (any stable 64-bit constant).
+    private const long MigrationAdvisoryLockKey = 727501;
+
     /// <summary>Apply any pending EF migrations. Called once on service start so a fresh stack
-    /// reaches a usable schema without a manual migration step (DoD: compose up reaches green).</summary>
+    /// reaches a usable schema without a manual migration step (DoD: compose up reaches green).
+    ///
+    /// The Event Subscriber and the projection-api share this DB and both migrate on start. EF's
+    /// migrations-history lock is released between individual migrations, so with more than one pending
+    /// migration two migrators can interleave and one re-applies a migration the other just did
+    /// ("column already exists"). Hold a Postgres session <c>pg_advisory_lock</c> across the whole
+    /// sequence so it runs exactly once; the second migrator then finds nothing pending.</summary>
     public static async Task MigrateProjectionAsync(this IServiceProvider services, CancellationToken ct = default)
     {
         await using var scope = services.CreateAsyncScope();
         var db = scope.ServiceProvider.GetRequiredService<ProjectionDbContext>();
+        var connection = db.Database.GetDbConnection();
+
+        await connection.OpenAsync(ct);
+        try
+        {
+            await ExecuteAsync(connection, $"SELECT pg_advisory_lock({MigrationAdvisoryLockKey})", ct);
+            try
+            {
                 await db.Database.MigrateAsync(ct);
             }
+            finally
+            {
+                await ExecuteAsync(connection, $"SELECT pg_advisory_unlock({MigrationAdvisoryLockKey})", ct);
+            }
+        }
+        finally
+        {
+            await connection.CloseAsync();
+        }
+    }
+
+    private static async Task ExecuteAsync(System.Data.Common.DbConnection connection, string sql, CancellationToken ct)
+    {
+        await using var command = connection.CreateCommand();
+        command.CommandText = sql;
+        await command.ExecuteNonQueryAsync(ct);
+    }
 }

services/projection-api/ProjectionApi.Api/Program.cs

@@ -10,8 +10,9 @@ builder.Services.AddProjectionReadModel(connectionString);
 
 var app = builder.Build();
 
-// Ensure the schema exists before serving reads. EF serialises concurrent migrators via the
+// Ensure the schema exists before serving reads. The Event Subscriber migrates this shared DB too;
-// migrations-history lock, so it is safe that the Event Subscriber migrates too.
+// MigrateProjectionAsync serialises concurrent migrators with a session advisory lock so the whole
+// migration sequence runs exactly once (see ServiceCollectionExtensions).
 await app.Services.MigrateProjectionAsync();
 
 app.MapGet("/health", () => "Healthy");
@@ -22,7 +23,7 @@ app.MapGet("/register", async (ProjectionDbContext db, CancellationToken ct) =>
 {
     var rows = await db.RegisterEntries
         .OrderBy(r => r.Id)
-        .Select(r => new RegisterEntryDto(r.Id, r.Status, r.Bsn, r.NaamPlaceholder))
+        .Select(r => new RegisterEntryDto(r.Id, r.Status, r.Reference, r.Bsn, r.NaamPlaceholder))
         .ToListAsync(ct);
     return Results.Ok(rows);
 });
@@ -31,13 +32,13 @@ app.MapGet("/register/{id}", async (string id, ProjectionDbContext db, Cancellat
 {
     var row = await db.RegisterEntries
         .Where(r => r.Id == id)
-        .Select(r => new RegisterEntryDto(r.Id, r.Status, r.Bsn, r.NaamPlaceholder))
+        .Select(r => new RegisterEntryDto(r.Id, r.Status, r.Reference, r.Bsn, r.NaamPlaceholder))
         .SingleOrDefaultAsync(ct);
     return row is null ? Results.NotFound() : Results.Ok(row);
 });
 
 await app.RunAsync();
 
-public sealed record RegisterEntryDto(string Id, string Status, string? Bsn, string? NaamPlaceholder);
+public sealed record RegisterEntryDto(string Id, string Status, string? Reference, string? Bsn, string? NaamPlaceholder);
 
 public partial class Program;

tests/acceptance/Features/EenRegistratieBeoordelen.feature

@@ -0,0 +1,26 @@
+# language: en
+# Drives S-12 (#13). A behandelaar picks up a submitted registration for beoordeling and decides it:
+# goedkeuren enters it in the register (INGESCHREVEN, the zaak's final status set via the ACL, §8.1),
+# afwijzen turns it down (AFGEWEZEN). This scenario exercises the use cases against in-memory
+# stand-ins for the ACL and the store; real Flowable user-task claim/complete arrives in a later
+# sub-slice and is verified live.
+Feature: Een registratie beoordelen
+  Als behandelaar wil ik een ingediende registratie beoordelen
+  zodat deze wordt ingeschreven of afgewezen.
+
+  Scenario: Goedkeuren schrijft de registratie in via de ACL
+    Given a submitted registration with an opened zaak
+    When the behandelaar takes it into behandeling
+    Then the registration has status "INBEHANDELING"
+    When the behandelaar decides "goedkeuren"
+    Then the registration has status "INGESCHREVEN"
+    And the zaak's final status is set via the ACL
+    And the beoordeling task is completed with "goedkeuren"
+
+  Scenario: Afwijzen wijst de registratie af zonder de ACL
+    Given a submitted registration with an opened zaak
+    When the behandelaar takes it into behandeling
+    And the behandelaar decides "afwijzen"
+    Then the registration has status "AFGEWEZEN"
+    And the ACL is not asked to set the zaak status
+    And the beoordeling task is completed with "afwijzen"

tests/acceptance/Steps/BffToegangSteps.cs

@@ -31,7 +31,7 @@ public sealed class BffToegangSteps : IDisposable
     [Given("the projection contains a zaak \"(.*)\" for BSN \"(.*)\"")]
     public void GivenTheProjectionContains(string zaakId, string bsn)
     {
-        _host.Projection.Entries.Add(new ProjectionEntry(zaakId, "INGEDIEND", bsn, null));
+        _host.Projection.Entries.Add(new ProjectionEntry(zaakId, "INGEDIEND", "REG-" + zaakId, bsn, null));
         _client = _host.CreateClient();
     }
 

tests/acceptance/Steps/EenRegistratieBeoordelenSteps.cs

@@ -0,0 +1,65 @@
+using Acceptance.Support;
+using Big.Application;
+using Big.Domain;
+using Reqnroll;
+using Xunit;
+
+namespace Acceptance.Steps;
+
+/// <summary>Bindings for <c>EenRegistratieBeoordelen.feature</c> (S-12). Drives the TakeIntoBehandeling
+/// transition and the BeoordeelRegistratie use case against in-memory ports; one instance per scenario.
+/// Scoped to this feature so its "the registration has status" step does not clash with the identically
+/// phrased (but differently-asserting) step in <see cref="RegistratieIndienenSteps"/>.</summary>
+[Binding]
+[Scope(Feature = "Een registratie beoordelen")]
+public sealed class EenRegistratieBeoordelenSteps
+{
+    private readonly InMemoryAclClient _acl = new();
+    private readonly InMemoryRegistrationStore _store = new();
+    private readonly InMemoryUserTaskClient _tasks = new();
+    private RegistrationId _id;
+
+    [Given("a submitted registration with an opened zaak")]
+    public async Task GivenASubmittedRegistrationWithAnOpenedZaak()
+    {
+        var registration = Registration.Submit("123456782");
+        registration.AttachZaak(InMemoryAclClient.OpenedZaakUrl);
+        await _store.SaveAsync(registration);
+        _id = registration.Id;
+        // The process has parked at the Beoordelen user task awaiting the behandelaar.
+        _tasks.Open(_id);
+    }
+
+    [When("the behandelaar takes it into behandeling")]
+    public async Task WhenTheBehandelaarTakesItIntoBehandeling()
+    {
+        var registration = await _store.GetAsync(_id);
+        registration!.TakeIntoBehandeling();
+        await _store.SaveAsync(registration);
+    }
+
+    [When("the behandelaar decides \"(.*)\"")]
+    public async Task WhenTheBehandelaarDecides(string besluit)
+        => await new BeoordeelRegistratie(_store, _acl, _tasks).HandleAsync(
+            new BeoordeelRegistratieCommand(_id, Enum.Parse<BeoordelingsBesluit>(besluit, ignoreCase: true)));
+
+    [Then("the registration has status \"(.*)\"")]
+    public async Task ThenTheRegistrationHasStatus(string expected)
+    {
+        var registration = await _store.GetAsync(_id);
+        Assert.NotNull(registration);
+        Assert.Equal(expected, registration.Status.ToString().ToUpperInvariant());
+    }
+
+    [Then("the zaak's final status is set via the ACL")]
+    public void ThenTheZaakFinalStatusIsSetViaTheAcl()
+        => Assert.Equal(InMemoryAclClient.OpenedZaakUrl, _acl.ApprovedZaakUrl);
+
+    [Then("the ACL is not asked to set the zaak status")]
+    public void ThenTheAclIsNotAskedToSetTheZaakStatus()
+        => Assert.Null(_acl.ApprovedZaakUrl);
+
+    [Then("the beoordeling task is completed with \"(.*)\"")]
+    public void ThenTheBeoordelingTaskIsCompletedWith(string besluit)
+        => Assert.Equal(Enum.Parse<BeoordelingsBesluit>(besluit, ignoreCase: true), _tasks.Completed?.Besluit);
+}

tests/acceptance/Steps/EenZaakOpenenSteps.cs

@@ -18,7 +18,7 @@ public sealed class EenZaakOpenenSteps
 
     [Given("a domain registration for BSN \"(.*)\"")]
     public void GivenADomainRegistrationForBsn(string bsn)
-        => _registration = new DomainRegistration(bsn);
+        => _registration = new DomainRegistration(bsn, "ACC-REF-1");
 
     [Given("the ACL is configured with these defaults:")]
     public void GivenTheAclIsConfiguredWithTheseDefaults(DataTable defaults)

tests/acceptance/Steps/RegisterProjectieBijwerkenSteps.cs

@@ -17,7 +17,8 @@ public sealed class RegisterProjectieBijwerkenSteps
     private readonly NotificationProjector _projector;
     private Notification? _notification;
 
-    public RegisterProjectieBijwerkenSteps() => _projector = new NotificationProjector(_log, _store);
+    public RegisterProjectieBijwerkenSteps()
+        => _projector = new NotificationProjector(_log, _store, new InMemoryAclReferenceClient());
 
     [Given("a zaak is created in OpenZaak with id \"(.*)\"")]
     public void GivenAZaakIsCreatedInOpenZaakWithId(string id)

tests/acceptance/Support/BffAcceptanceHost.cs

@@ -68,6 +68,12 @@ public sealed class CapturingDomainClient : IDomainClient
         SubmittedBsn = bsn;
         return Task.FromResult(new SubmitAccepted("reg-acc-1", "Ingediend"));
     }
+
+    public Task<IReadOnlyList<WerkbakItem>> GetWerkbakAsync(CancellationToken ct = default)
+        => Task.FromResult<IReadOnlyList<WerkbakItem>>([]);
+
+    public Task DecideAsync(string registrationId, string besluit, CancellationToken ct = default)
+        => Task.CompletedTask;
 }
 
 /// <summary>Serves configurable projection rows.</summary>

tests/acceptance/Support/InMemoryDomainPorts.cs

@@ -26,11 +26,13 @@ public sealed class InMemoryAclClient : IAclClient
     public static readonly Uri OpenedZaakUrl = new("http://openzaak/zaken/api/v1/zaken/acc-zaak");
 
     public string? OpenedForBsn { get; private set; }
+    public string? OpenedWithReference { get; private set; }
     public Uri? ApprovedZaakUrl { get; private set; }
 
-    public Task<Uri> OpenZaakAsync(string bsn, CancellationToken ct = default)
+    public Task<Uri> OpenZaakAsync(string bsn, string reference, CancellationToken ct = default)
     {
         OpenedForBsn = bsn;
+        OpenedWithReference = reference;
         return Task.FromResult(OpenedZaakUrl);
     }
 
@@ -41,6 +43,29 @@ public sealed class InMemoryAclClient : IAclClient
     }
 }
 
+/// <summary>An in-memory user-task client for the beoordeling acceptance scenario: it holds one open
+/// Beoordelen task per registration and records the besluit each is completed with.</summary>
+public sealed class InMemoryUserTaskClient : IUserTaskClient
+{
+    private readonly List<BeoordelingTask> _open = [];
+
+    public (string TaskId, BeoordelingsBesluit Besluit)? Completed { get; private set; }
+
+    public void Open(RegistrationId registrationId) => _open.Add(new BeoordelingTask($"task-{registrationId}", registrationId));
+
+    public Task<IReadOnlyList<BeoordelingTask>> GetOpenBeoordelingenAsync(CancellationToken ct = default)
+        => Task.FromResult<IReadOnlyList<BeoordelingTask>>(_open);
+
+    public Task ClaimAsync(string taskId, string behandelaar, CancellationToken ct = default) => Task.CompletedTask;
+
+    public Task CompleteBeoordelingAsync(string taskId, BeoordelingsBesluit besluit, CancellationToken ct = default)
+    {
+        Completed = (taskId, besluit);
+        _open.RemoveAll(t => t.TaskId == taskId);
+        return Task.CompletedTask;
+    }
+}
+
 /// <summary>An in-memory registration store for the domain acceptance scenario.</summary>
 public sealed class InMemoryRegistrationStore : IRegistrationStore
 {

tests/acceptance/Support/InMemoryProjectionStores.cs

@@ -38,3 +38,11 @@ public sealed class InMemoryProjectionStore : IProjectionStore
     public IReadOnlyList<RegisterEntry> RowsFor(string id)
         => [.. _byId.Values.Where(e => e.Id == id)];
 }
+
+/// <summary>A fake ACL client for the projection acceptance scenario: returns a reference derived
+/// from the zaak, so the projector can enrich rows without a running ACL (#78).</summary>
+public sealed class InMemoryAclReferenceClient : IAclClient
+{
+    public Task<string> GetZaakReferenceAsync(Uri zaakUrl, CancellationToken ct = default)
+        => Task.FromResult("REG-" + zaakUrl.Segments[^1].Trim('/'));
+}

tests/acceptance/Support/InMemoryZaakGateway.cs

@@ -24,4 +24,7 @@ public sealed class InMemoryZaakGateway : IZaakGateway
         Approved = (zaakUrl, zaaktypeUrl, datumStatusGezet);
         return Task.CompletedTask;
     }
+
+    public Task<string> GetZaakIdentificatieAsync(Uri zaakUrl, CancellationToken ct = default)
+        => Task.FromResult("ACC-REF-1");
 }

tests/e2e/registration.spec.ts

@@ -26,15 +26,22 @@ test('DigiD login → submit → public INGEDIEND → approve → public INGESCH
 
   // The openbaar register (anonymous, its own origin) shows the submitted entry once the projection
   // catches up. The projection updates asynchronously (NRC → event-subscriber), and the register loads
-  // on open, so reload until a submitted (INGEDIEND) row appears.
+  // on open, so reload until *this* submission's row appears. We poll on the reference cell (not a
+  // generic INGEDIEND cell): the shared verify stack already holds INGEDIEND rows from earlier checks,
+  // so a status-only poll would short-circuit on a stale row before our row is projected.
   await page.goto('http://openbaar/');
   await expect(page.getByRole('heading', { name: /Openbaar BIG-register/i })).toBeVisible();
+
+  // #78: the reference shown in the public register must be the exact one the citizen saw on the
+  // submit confirmation — no mismatch between the two portals.
   await expect
     .poll(async () => {
       await page.reload();
-      return page.getByRole('cell', { name: 'INGEDIEND' }).count();
+      return page.getByRole('cell', { name: reference }).count();
     }, { timeout: 30_000, intervals: [1_000, 2_000, 3_000, 5_000] })
     .toBeGreaterThan(0);
+  await expect(page.getByRole('row', { name: reference }).getByRole('cell', { name: 'INGEDIEND' }))
+    .toBeVisible();
 
   // Approve via the temporary admin endpoint (reached directly on the compose network, as a
   // behandelaar would until the behandel-portal exists — S-12). The zaak is opened off the request
@@ -49,11 +56,12 @@ test('DigiD login → submit → public INGEDIEND → approve → public INGESCH
   const approve = await request.post(`http://domain:8080/registrations/${reference}/approve`);
   expect(approve.status()).toBe(204);
 
-  // The approval flows back to the projection; the openbaar register now shows it as INGESCHREVEN.
+  // The approval flows back to the projection; the openbaar register now shows *our* row (matched by
+  // its reference) as INGESCHREVEN.
   await expect
     .poll(async () => {
       await page.reload();
-      return page.getByRole('cell', { name: 'INGESCHREVEN' }).count();
+      return page.getByRole('row', { name: reference }).getByRole('cell', { name: 'INGESCHREVEN' }).count();
     }, { timeout: 30_000, intervals: [1_000, 2_000, 3_000, 5_000] })
     .toBeGreaterThan(0);
 });

workflows/registratie.bpmn

@@ -6,9 +6,12 @@
              xmlns:omgdi="http://www.omg.org/spec/DD/20100524/DI"
              targetNamespace="http://respellion.nl/big">
 
-  <!-- S-03: minimal "Registratie ontvangen" flow.
+  <!-- Registratie ontvangen flow.
-       start -> external-worker task (OpenZaakAanmaken) -> end.
+       start -> external-worker task (OpenZaakAanmaken) -> Beoordelen (behandelaar user task) -> end.
-       The external task is handled by the Workflow Client / ACL in later slices. -->
+       S-03 added the external task (Workflow Client / ACL). S-12 adds the behandelaar's beoordeling
+       as a user task: the process parks here until a behandelaar claims and completes it with a
+       `besluit` (goedkeuren/afwijzen). The registrationId set at start rides along as a process
+       variable so the werkbak can correlate each task back to its aggregate. -->
   <process id="registratie" name="Registratie ontvangen" isExecutable="true">
 
     <startEvent id="start" name="Registratie ontvangen"/>
@@ -19,9 +22,13 @@
                  flowable:type="external-worker"
                  flowable:topic="OpenZaakAanmaken"/>
 
-    <sequenceFlow id="flow2" sourceRef="OpenZaakAanmaken" targetRef="end"/>
+    <sequenceFlow id="flow2" sourceRef="OpenZaakAanmaken" targetRef="Beoordelen"/>
 
-    <endEvent id="end" name="Zaak aangemaakt"/>
+    <userTask id="Beoordelen" name="Beoordelen" flowable:candidateGroups="behandelaar"/>
+
+    <sequenceFlow id="flow3" sourceRef="Beoordelen" targetRef="end"/>
+
+    <endEvent id="end" name="Registratie beoordeeld"/>
   </process>
 
   <bpmndi:BPMNDiagram id="diagram">
@@ -32,8 +39,11 @@
       <bpmndi:BPMNShape id="s_task" bpmnElement="OpenZaakAanmaken">
         <omgdc:Bounds x="200" y="85" width="120" height="60"/>
       </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape id="s_beoordelen" bpmnElement="Beoordelen">
+        <omgdc:Bounds x="390" y="85" width="120" height="60"/>
+      </bpmndi:BPMNShape>
       <bpmndi:BPMNShape id="s_end" bpmnElement="end">
-        <omgdc:Bounds x="400" y="100" width="30" height="30"/>
+        <omgdc:Bounds x="580" y="100" width="30" height="30"/>
       </bpmndi:BPMNShape>
       <bpmndi:BPMNEdge id="e_flow1" bpmnElement="flow1">
         <omgdi:waypoint x="130" y="115"/>
@@ -41,7 +51,11 @@
       </bpmndi:BPMNEdge>
       <bpmndi:BPMNEdge id="e_flow2" bpmnElement="flow2">
         <omgdi:waypoint x="320" y="115"/>
-        <omgdi:waypoint x="400" y="115"/>
+        <omgdi:waypoint x="390" y="115"/>
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNEdge id="e_flow3" bpmnElement="flow3">
+        <omgdi:waypoint x="510" y="115"/>
+        <omgdi:waypoint x="580" y="115"/>
       </bpmndi:BPMNEdge>
     </bpmndi:BPMNPlane>
   </bpmndi:BPMNDiagram>