Merge branch 'main' into fix/91-local-compose-parity

## What & why

Third sub-slice of **S-11 · Withdrawal (Flow 3)** (#12) — the **owner-scoped BFF withdraw endpoint** (backend). S-11a/b made a withdrawal transition the aggregate and cancel the workflow; this adds the citizen-facing entry point through the BFF, gated to the registration's owner.

- **Domain**: `WithdrawRegistrationCommand` carries the caller's `bsn`; the handler returns a `WithdrawOutcome` and refuses a bsn that doesn't own the registration. Unknown and not-owned are **both 404** (indistinguishable — ownership isn't revealed). `POST /registrations/{id}/withdraw` takes `{bsn}` and maps the outcome (204/404).
- **BFF**: `POST /self-service/registrations/{id}/withdraw` (DigiD-authenticated) forwards the token's `bsn` to the domain and relays 204/404. The BFF authenticates; the domain owner-scopes (an aggregate invariant, not the domain doing auth).
- OpenAPI spec + Angular client regenerated for the new endpoint.
- `run-domain-check.sh` withdrawal step now sends the owner `bsn` (verify-stack).

Refs #12 — the self-service "trek aanvraag in" button + e2e (S-11c-2) closes it.

## Definition of Done

- [x] Linked Gitea issue (#12).
- [x] Failing tests committed before the implementation.
- [x] Implementation makes the tests pass.
- [x] Conventional Commits referencing the issue (`refs #12`).
- [ ] CI green — all Gitea Actions jobs.
- [x] `docker compose up` unaffected.
- [x] No ADR needed (owner-scoping is an aggregate invariant; no boundary change).
- [x] Docs — the user-visible demo note lands with S-11c-2.

## Notes for reviewers

- **Full local gate run before pushing this time** (lessons from #89): `dotnet format --verify-no-changes` clean; `make unit` green — Acl 27, EventSubscriber 19, BFF 30, Acceptance 9, Big 95; `api-client` lint+test green.
- Owner mismatch returns 404 (not 403) so the portal can't be used to probe which references exist.

Reviewed-on: #90

.gitea/workflows/ci.yaml

@@ -157,7 +157,7 @@ jobs:
       # Log dump must precede teardown (which removes the containers).
       - name: Dump container logs on failure
         if: failure()
-        run: docker compose -f infra/docker-compose.yml logs --no-color --tail=100 oz-init openzaak nrc-init nrc-web nrc-celery nrc-beat flowable-db flowable-rest flowable-init keycloak acl bff domain projection-db event-subscriber projection-api self-service 2>&1 || true
+        run: docker compose -f infra/docker-compose.yml logs --no-color --tail=100 oz-init openzaak nrc-init nrc-web nrc-celery nrc-beat flowable-db flowable-rest flowable-init keycloak acl bff domain projection-db event-subscriber projection-api self-service openbaar behandel 2>&1 || true
       - name: Tear down
         if: always()
         run: make down

Makefile

@@ -10,7 +10,7 @@ COMPOSE    := infra/docker-compose.yml
 # Long-running services with a healthcheck — the smoke polls these for readiness
 # (infra/wait-healthy.sh). One-shot init jobs (oz-init, nrc-init, flowable-init)
 # are not polled; they only need to have run. See docs/runbooks/gitea-actions-gotchas.md.
-WAIT_SVCS  := openzaak nrc-web acl bff domain event-subscriber projection-api self-service openbaar
+WAIT_SVCS  := openzaak nrc-web acl bff domain event-subscriber projection-api self-service openbaar behandel
 # Config files (OpenZaak data.yaml, Keycloak realms, Flowable BPMN) are streamed
 # into external named volumes via `docker cp` (infra/seed-config.sh) instead of
 # bind-mounted, because bind mounts don't reach sibling containers on the

apps/behandel/Dockerfile

@@ -0,0 +1,23 @@
+# Multi-stage build for the behandel portal (Angular → nginx).
+# Build context is the repo root (the app needs the pnpm workspace + libs). See infra/docker-compose.yml.
+FROM node:24-slim AS build
+WORKDIR /src
+RUN corepack enable && corepack prepare pnpm@11.5.2 --activate
+
+# Restore first (cached unless the manifests change).
+COPY package.json pnpm-lock.yaml pnpm-workspace.yaml nx.json tsconfig.base.json eslint.config.mjs ./
+RUN pnpm install --frozen-lockfile
+
+# Sources (only what the app + its libs need).
+COPY apps/behandel apps/behandel
+COPY libs libs
+RUN pnpm nx build behandel
+
+FROM nginx:1.27-alpine AS runtime
+COPY apps/behandel/nginx.conf /etc/nginx/conf.d/default.conf
+COPY --from=build /src/dist/apps/behandel/browser /usr/share/nginx/html
+# Compose-time OIDC config: the browser (Playwright, on the compose network) reaches Keycloak by
+# service name, so the token issuer matches the BFF's medewerker authority (host-consistent, ADR-0013).
+RUN printf '{ "authority": "http://keycloak:8080/realms/medewerker" }\n' > /usr/share/nginx/html/config.json
+
+EXPOSE 80

apps/behandel/eslint.config.mjs

@@ -0,0 +1,34 @@
+import nx from '@nx/eslint-plugin';
+import baseConfig from '../../eslint.config.mjs';
+
+export default [
+  ...nx.configs['flat/angular'],
+  ...nx.configs['flat/angular-template'],
+  ...baseConfig,
+  {
+    files: ['**/*.ts'],
+    rules: {
+      '@angular-eslint/directive-selector': [
+        'error',
+        {
+          type: 'attribute',
+          prefix: 'app',
+          style: 'camelCase',
+        },
+      ],
+      '@angular-eslint/component-selector': [
+        'error',
+        {
+          type: 'element',
+          prefix: 'app',
+          style: 'kebab-case',
+        },
+      ],
+    },
+  },
+  {
+    files: ['**/*.html'],
+    // Override or add rules here
+    rules: {},
+  },
+];

apps/behandel/nginx.conf

@@ -0,0 +1,24 @@
+server {
+  listen 80;
+  server_name _;
+  root /usr/share/nginx/html;
+  index index.html;
+
+  # Resolve the BFF via Docker's embedded DNS at request time (variable proxy_pass), so nginx starts
+  # even before the BFF is up and picks up restarts — instead of failing to load the config.
+  resolver 127.0.0.11 ipv6=off valid=30s;
+
+  # Same-origin API: proxy the behandel endpoint group to the bff service. The api-client uses
+  # relative URLs, so the browser calls this origin and nginx forwards to the BFF — no CORS, and the
+  # medewerker token (same-origin) is attached by the app's interceptor (ADR-0013).
+  location /behandel/ {
+    set $bff http://bff:8080;
+    proxy_pass $bff;
+    proxy_set_header Host $host;
+  }
+
+  # SPA fallback — Angular client-side routing.
+  location / {
+    try_files $uri $uri/ /index.html;
+  }
+}

apps/behandel/project.json

@@ -0,0 +1,80 @@
+{
+  "name": "behandel",
+  "$schema": "../../node_modules/nx/schemas/project-schema.json",
+  "projectType": "application",
+  "prefix": "app",
+  "sourceRoot": "apps/behandel/src",
+  "tags": [],
+  "targets": {
+    "build": {
+      "executor": "@angular/build:application",
+      "outputs": ["{options.outputPath}"],
+      "defaultConfiguration": "production",
+      "options": {
+        "outputPath": "dist/apps/behandel",
+        "browser": "apps/behandel/src/main.ts",
+        "tsConfig": "apps/behandel/tsconfig.app.json",
+        "assets": [
+          {
+            "glob": "**/*",
+            "input": "apps/behandel/public"
+          }
+        ],
+        "styles": ["apps/behandel/src/styles.css"]
+      },
+      "configurations": {
+        "production": {
+          "budgets": [
+            {
+              "type": "initial",
+              "maximumWarning": "1mb",
+              "maximumError": "2mb"
+            },
+            {
+              "type": "anyComponentStyle",
+              "maximumWarning": "4kb",
+              "maximumError": "8kb"
+            }
+          ],
+          "outputHashing": "all"
+        },
+        "development": {
+          "optimization": false,
+          "extractLicenses": false,
+          "sourceMap": true
+        }
+      }
+    },
+    "serve": {
+      "continuous": true,
+      "executor": "@angular/build:dev-server",
+      "defaultConfiguration": "development",
+      "configurations": {
+        "production": {
+          "buildTarget": "behandel:build:production"
+        },
+        "development": {
+          "buildTarget": "behandel:build:development"
+        }
+      }
+    },
+    "lint": {
+      "executor": "@nx/eslint:lint"
+    },
+    "test": {
+      "executor": "@angular/build:unit-test",
+      "options": {
+        "watch": false
+      }
+    },
+    "serve-static": {
+      "continuous": true,
+      "executor": "@nx/web:file-server",
+      "options": {
+        "buildTarget": "behandel:build",
+        "staticFilePath": "dist/apps/behandel/browser",
+        "spa": true
+      }
+    }
+  }
+}

apps/behandel/public/config.json

@@ -0,0 +1,3 @@
+{
+  "authority": "http://localhost:8180/realms/medewerker"
+}

apps/behandel/src/app/app.config.spec.ts

@@ -0,0 +1,73 @@
+import { provideHttpClient, withInterceptors } from '@angular/common/http';
+import { HttpTestingController, provideHttpClientTesting } from '@angular/common/http/testing';
+import { TestBed } from '@angular/core/testing';
+import { BffApiV1Service } from 'api-client';
+import { authInterceptor } from 'auth';
+import { AbstractSecurityStorage, ConfigurationService } from 'angular-auth-oidc-client';
+import { SECURE_API_ROUTES } from './app.config';
+
+// Guards the medewerker token wiring end-to-end. The api-client calls the BFF with RELATIVE URLs, and
+// the angular-auth-oidc-client interceptor attaches the token only when `req.url` starts with a
+// configured secureRoute. A regression to an absolute origin makes the relative URL never match, so
+// the behandel calls go out unauthenticated and the BFF answers 401. This drives the REAL interceptor
+// and the REAL api-client against the REAL production route value (SECURE_API_ROUTES); only the config
+// source and token storage are faked, so the assertion turns on the actual route-matching.
+describe('behandel medewerker token wiring', () => {
+  let http: HttpTestingController;
+  let bff: BffApiV1Service;
+  const token = 'medewerker-access-token';
+
+  beforeEach(() => {
+    TestBed.configureTestingModule({
+      providers: [
+        provideHttpClient(withInterceptors([authInterceptor()])),
+        provideHttpClientTesting(),
+        {
+          provide: ConfigurationService,
+          useValue: {
+            hasAtLeastOneConfig: () => true,
+            getAllConfigurations: () => [{ configId: 'medewerker', secureRoutes: SECURE_API_ROUTES }],
+          },
+        },
+        {
+          // A signed-in session: the storage the interceptor's token lookup reads from.
+          provide: AbstractSecurityStorage,
+          useValue: {
+            read: () => JSON.stringify({ authzData: token, authnResult: { id_token: 'id-token' } }),
+            write: () => undefined,
+            remove: () => undefined,
+            clear: () => undefined,
+          },
+        },
+      ],
+    });
+    http = TestBed.inject(HttpTestingController);
+    bff = TestBed.inject(BffApiV1Service);
+  });
+
+  afterEach(() => http.verify());
+
+  it('attaches the bearer token to the relative werkbak call', () => {
+    bff.getBehandelWerkbak().subscribe();
+
+    const req = http.expectOne('/behandel/werkbak');
+    expect(req.request.headers.get('Authorization')).toBe(`Bearer ${token}`);
+    req.flush([]);
+  });
+
+  it('attaches the bearer token to the relative decide call', () => {
+    bff.postBehandelRegistrationsIdDecide('reg-1', { besluit: 'goedkeuren' }).subscribe();
+
+    const req = http.expectOne('/behandel/registrations/reg-1/decide');
+    expect(req.request.headers.get('Authorization')).toBe(`Bearer ${token}`);
+    req.flush(null);
+  });
+
+  it('leaves the anonymous openbaar register call unauthenticated', () => {
+    bff.getOpenbaarRegister().subscribe();
+
+    const req = http.expectOne((r) => r.url === '/openbaar/register');
+    expect(req.request.headers.has('Authorization')).toBe(false);
+    req.flush([]);
+  });
+});

apps/behandel/src/app/app.config.ts

@@ -0,0 +1,39 @@
+import { provideHttpClient, withInterceptors } from '@angular/common/http';
+import { ApplicationConfig, provideBrowserGlobalErrorListeners } from '@angular/core';
+import { provideRouter } from '@angular/router';
+import { authInterceptor, provideMedewerkerAuth } from 'auth';
+import { appRoutes } from './app.routes';
+
+/** Environment-specific settings fetched from /config.json at startup (see main.ts). */
+export interface RuntimeConfig {
+  /** The Keycloak `medewerker` realm issuer as the browser reaches it (dev: localhost; compose: keycloak:8080). */
+  authority: string;
+}
+
+/**
+ * Route prefixes whose requests carry the medewerker token. These MUST match the **relative** URLs
+ * the api-client actually calls (same-origin via the nginx proxy) — the interceptor matches on
+ * `req.url`, which stays relative, so an absolute origin would never match and the token would go
+ * unattached. Only `/behandel/` is secured; the app calls no other endpoint group.
+ */
+export const SECURE_API_ROUTES = ['/behandel/'];
+
+/**
+ * Build the app providers from runtime config. `redirectUrl` is the app's own origin (where Keycloak
+ * redirects back). `secureRoutes` uses {@link SECURE_API_ROUTES} — relative prefixes, not the origin.
+ */
+export function appConfig(runtime: RuntimeConfig): ApplicationConfig {
+  const origin = typeof window !== 'undefined' ? window.location.origin : '/';
+  return {
+    providers: [
+      provideBrowserGlobalErrorListeners(),
+      provideRouter(appRoutes),
+      provideHttpClient(withInterceptors([authInterceptor()])),
+      provideMedewerkerAuth({
+        authority: runtime.authority,
+        redirectUrl: origin,
+        secureRoutes: SECURE_API_ROUTES,
+      }),
+    ],
+  };
+}

apps/behandel/src/app/app.html

@@ -0,0 +1 @@
+<router-outlet></router-outlet>

apps/behandel/src/app/app.routes.ts

@@ -0,0 +1,7 @@
+import { Route } from '@angular/router';
+import { authenticatedGuard } from 'auth';
+import { WerkbakPage } from './werkbak/werkbak-page';
+
+export const appRoutes: Route[] = [
+  { path: '', component: WerkbakPage, canActivate: [authenticatedGuard] },
+];

apps/behandel/src/app/app.spec.ts

@@ -0,0 +1,15 @@
+import { provideRouter } from '@angular/router';
+import { render, screen } from '@testing-library/angular';
+import { App } from './app';
+
+describe('App', () => {
+  it('renders the router outlet shell', async () => {
+    const { container } = await render(App, {
+      providers: [provideRouter([])],
+    });
+
+    // The shell is a thin host for routed pages (the WerkbakPage owns the heading).
+    expect(container.querySelector('router-outlet')).toBeTruthy();
+    expect(screen).toBeTruthy();
+  });
+});

apps/behandel/src/app/app.ts

@@ -0,0 +1,12 @@
+import { Component } from '@angular/core';
+import { RouterModule } from '@angular/router';
+
+@Component({
+  imports: [RouterModule],
+  selector: 'app-root',
+  templateUrl: './app.html',
+  styleUrl: './app.css',
+})
+export class App {
+  protected title = 'behandel';
+}

apps/behandel/src/app/werkbak/werkbak-page.html

@@ -0,0 +1,64 @@
+<main utrecht-document class="utrecht-theme">
+  <utrecht-article>
+    <utrecht-heading-1>Werkbak</utrecht-heading-1>
+    <p utrecht-paragraph>
+      Registraties die wachten op beoordeling. Keur elke registratie goed of wijs deze af.
+    </p>
+
+    @if (loading()) {
+      <p utrecht-paragraph role="status">Bezig met laden…</p>
+    } @else if (failed()) {
+      <p utrecht-paragraph role="alert">
+        Kon de werkbak niet laden. Controleer of je als behandelaar bent ingelogd en probeer het
+        opnieuw.
+      </p>
+    } @else if (loaded() && items().length === 0) {
+      <p utrecht-paragraph role="status">De werkbak is leeg.</p>
+    } @else if (items().length > 0) {
+      <table utrecht-table>
+        <caption>
+          Registraties in behandeling
+        </caption>
+        <thead>
+          <tr>
+            <th scope="col">Referentie</th>
+            <th scope="col">BSN</th>
+            <th scope="col">Status</th>
+            <th scope="col">Actie</th>
+          </tr>
+        </thead>
+        <tbody>
+          @for (item of items(); track item.registrationId) {
+            <tr>
+              <td>{{ item.registrationId }}</td>
+              <td>{{ item.bsn }}</td>
+              <td>{{ item.status }}</td>
+              <td>
+                <button
+                  utrecht-button
+                  appearance="primary-action-button"
+                  type="button"
+                  [attr.aria-label]="'Goedkeuren ' + item.registrationId"
+                  [disabled]="deciding() === item.registrationId"
+                  (click)="decide(item.registrationId, 'goedkeuren')"
+                >
+                  Goedkeuren
+                </button>
+                <button
+                  utrecht-button
+                  appearance="secondary-action-button"
+                  type="button"
+                  [attr.aria-label]="'Afwijzen ' + item.registrationId"
+                  [disabled]="deciding() === item.registrationId"
+                  (click)="decide(item.registrationId, 'afwijzen')"
+                >
+                  Afwijzen
+                </button>
+              </td>
+            </tr>
+          }
+        </tbody>
+      </table>
+    }
+  </utrecht-article>
+</main>

apps/behandel/src/app/werkbak/werkbak-page.spec.ts

@@ -0,0 +1,110 @@
+import { signal } from '@angular/core';
+import { fireEvent, render, screen } from '@testing-library/angular';
+import { of, throwError } from 'rxjs';
+import { BffApiV1Service, type WerkbakItem } from 'api-client';
+import { AuthService } from 'auth';
+import { axe } from 'vitest-axe';
+import { WerkbakPage } from './werkbak-page';
+
+const sample: WerkbakItem[] = [
+  { registrationId: 'reg-1', bsn: '123456782', status: 'InBehandeling' },
+  { registrationId: 'reg-2', bsn: '111222333', status: 'InBehandeling' },
+];
+
+class FakeAuth extends AuthService {
+  readonly isAuthenticated = signal(true);
+  readonly bsn = signal<string | undefined>(undefined);
+  override readonly roles = signal<readonly string[]>(['behandelaar']);
+  login(): void {
+    /* not exercised here */
+  }
+  logout(): void {
+    /* spied in tests */
+  }
+}
+
+function setup(
+  overrides: {
+    getBehandelWerkbak?: ReturnType<typeof vi.fn>;
+    postBehandelRegistrationsIdDecide?: ReturnType<typeof vi.fn>;
+  } = {},
+) {
+  const getBehandelWerkbak =
+    overrides.getBehandelWerkbak ?? vi.fn().mockReturnValue(of(sample));
+  const postBehandelRegistrationsIdDecide =
+    overrides.postBehandelRegistrationsIdDecide ?? vi.fn().mockReturnValue(of(undefined));
+  return {
+    getBehandelWerkbak,
+    postBehandelRegistrationsIdDecide,
+    providers: [
+      {
+        provide: BffApiV1Service,
+        useValue: { getBehandelWerkbak, postBehandelRegistrationsIdDecide },
+      },
+      { provide: AuthService, useClass: FakeAuth },
+    ],
+  };
+}
+
+describe('WerkbakPage', () => {
+  it('lists the registrations awaiting beoordeling on open', async () => {
+    const { getBehandelWerkbak, providers } = setup();
+    await render(WerkbakPage, { providers });
+
+    expect(getBehandelWerkbak).toHaveBeenCalled();
+    expect(await screen.findByText('reg-1')).toBeTruthy();
+    expect(screen.getByText('123456782')).toBeTruthy();
+    expect(screen.getByText('reg-2')).toBeTruthy();
+  });
+
+  it('approves a registration (goedkeuren) and refreshes the werkbak', async () => {
+    const { getBehandelWerkbak, postBehandelRegistrationsIdDecide, providers } = setup();
+    await render(WerkbakPage, { providers });
+
+    fireEvent.click((await screen.findAllByRole('button', { name: /goedkeuren/i }))[0]);
+
+    expect(postBehandelRegistrationsIdDecide).toHaveBeenCalledWith('reg-1', {
+      besluit: 'goedkeuren',
+    });
+    // Reloaded after the decision: once on open, once after deciding.
+    expect(getBehandelWerkbak).toHaveBeenCalledTimes(2);
+  });
+
+  it('rejects a registration (afwijzen) via the decide endpoint', async () => {
+    const { postBehandelRegistrationsIdDecide, providers } = setup();
+    await render(WerkbakPage, { providers });
+
+    fireEvent.click((await screen.findAllByRole('button', { name: /afwijzen/i }))[0]);
+
+    expect(postBehandelRegistrationsIdDecide).toHaveBeenCalledWith('reg-1', {
+      besluit: 'afwijzen',
+    });
+  });
+
+  it('shows an empty state when the werkbak has no items', async () => {
+    const { providers } = setup({ getBehandelWerkbak: vi.fn().mockReturnValue(of([])) });
+    await render(WerkbakPage, { providers });
+
+    expect(await screen.findByText(/werkbak is leeg/i)).toBeTruthy();
+  });
+
+  it('surfaces a load failure instead of swallowing it', async () => {
+    const { providers } = setup({
+      getBehandelWerkbak: vi.fn().mockReturnValue(throwError(() => new Error('403'))),
+    });
+    await render(WerkbakPage, { providers });
+
+    expect(await screen.findByText(/kon de werkbak niet laden/i)).toBeTruthy();
+  });
+
+  it('has no WCAG 2.1 AA violations', async () => {
+    document.documentElement.lang = 'nl';
+    const { container } = await render(WerkbakPage, { providers: setup().providers });
+
+    const results = await axe(container, {
+      runOnly: { type: 'tag', values: ['wcag2a', 'wcag2aa', 'wcag21a', 'wcag21aa'] },
+    });
+
+    expect(results.violations).toEqual([]);
+  });
+});

apps/behandel/src/app/werkbak/werkbak-page.ts

@@ -0,0 +1,65 @@
+import { Component, inject, signal } from '@angular/core';
+import { BffApiV1Service, type WerkbakItem } from 'api-client';
+import { UtrechtComponentsModule } from 'ui';
+
+/** The two decisions a behandelaar can make; the BFF validates these exact values (ADR-0013). */
+type Besluit = 'goedkeuren' | 'afwijzen';
+
+/**
+ * The behandel werkbak: a signed-in behandelaar sees the registrations awaiting beoordeling (the open
+ * Flowable `Beoordelen` tasks, read through the domain) and decides each — goedkeuren or afwijzen. A
+ * decision posts to the BFF, which applies the domain transition and completes the workflow task
+ * (ADR-0013; S-12). After a decision the werkbak refreshes so the handled item drops off the list.
+ */
+@Component({
+  selector: 'app-werkbak-page',
+  imports: [UtrechtComponentsModule],
+  templateUrl: './werkbak-page.html',
+})
+export class WerkbakPage {
+  private readonly bff = inject(BffApiV1Service);
+
+  protected readonly items = signal<WerkbakItem[]>([]);
+  protected readonly loading = signal(false);
+  protected readonly loaded = signal(false);
+  protected readonly failed = signal(false);
+  protected readonly deciding = signal<string | undefined>(undefined);
+
+  constructor() {
+    this.load();
+  }
+
+  load(): void {
+    this.loading.set(true);
+    this.failed.set(false);
+    this.bff.getBehandelWerkbak().subscribe({
+      next: (rows: WerkbakItem[]) => {
+        this.items.set(rows);
+        this.loading.set(false);
+        this.loaded.set(true);
+      },
+      // Surface the failure (e.g. 403 for a non-behandelaar) instead of swallowing it.
+      error: () => {
+        this.items.set([]);
+        this.loading.set(false);
+        this.loaded.set(true);
+        this.failed.set(true);
+      },
+    });
+  }
+
+  decide(registrationId: string, besluit: Besluit): void {
+    this.deciding.set(registrationId);
+    this.bff.postBehandelRegistrationsIdDecide(registrationId, { besluit }).subscribe({
+      // Refresh so the decided registration drops off the werkbak (its task is now completed).
+      next: () => {
+        this.deciding.set(undefined);
+        this.load();
+      },
+      error: () => {
+        this.deciding.set(undefined);
+        this.failed.set(true);
+      },
+    });
+  }
+}

apps/behandel/src/index.html

@@ -0,0 +1,13 @@
+<!doctype html>
+<html lang="nl">
+  <head>
+    <meta charset="utf-8" />
+    <title>Behandelportaal BIG-register</title>
+    <base href="/" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <link rel="icon" type="image/x-icon" href="favicon.ico" />
+  </head>
+  <body>
+    <app-root></app-root>
+  </body>
+</html>

apps/behandel/src/main.ts

@@ -0,0 +1,10 @@
+import { bootstrapApplication } from '@angular/platform-browser';
+import { App } from './app/app';
+import { appConfig, type RuntimeConfig } from './app/app.config';
+
+// Load environment config before bootstrap so the OIDC authority is set per environment
+// (dev: localhost; compose: keycloak:8080) from a single build — 12-factor (S-08d).
+fetch('config.json')
+  .then((response) => response.json() as Promise<RuntimeConfig>)
+  .then((config) => bootstrapApplication(App, appConfig(config)))
+  .catch((err) => console.error(err));

apps/behandel/src/styles.css

@@ -0,0 +1,2 @@
+/* NL Design System theme — Utrecht design tokens (docs/frontend-decisions.md). */
+@import '@utrecht/design-tokens/dist/index.css';

apps/behandel/tsconfig.app.json

@@ -0,0 +1,9 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "../../dist/out-tsc",
+    "types": []
+  },
+  "include": ["src/**/*.ts"],
+  "exclude": ["src/**/*.spec.ts", "src/**/*.test.ts"]
+}

apps/behandel/tsconfig.json

@@ -0,0 +1,31 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "strict": true,
+    "noImplicitOverride": true,
+    "noPropertyAccessFromIndexSignature": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "isolatedModules": true,
+    "target": "es2022",
+    "moduleResolution": "bundler",
+    "emitDecoratorMetadata": false,
+    "module": "preserve"
+  },
+  "angularCompilerOptions": {
+    "enableI18nLegacyMessageIdFormat": false,
+    "strictInjectionParameters": true,
+    "strictInputAccessModifiers": true,
+    "strictTemplates": true
+  },
+  "files": [],
+  "include": [],
+  "references": [
+    {
+      "path": "./tsconfig.app.json"
+    },
+    {
+      "path": "./tsconfig.spec.json"
+    }
+  ]
+}

apps/behandel/tsconfig.spec.json

@@ -0,0 +1,8 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "../../dist/out-tsc",
+    "types": ["vitest/globals"]
+  },
+  "include": ["src/**/*.ts", "src/**/*.d.ts"]
+}

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/architecture/adr-0014-withdrawal-cancels-the-process.md

@@ -0,0 +1,72 @@
+# ADR-0014: Withdrawal cancels the registratie process via a BPMN message event
+
+- **Status:** Accepted
+- **Date:** 2026-07-16
+- **Deciders:** Respellion engineering
+- **Relates to:** S-11 (#12); builds on ADR-0009 (external-task worker / Workflow Client), ADR-0013
+  (behandel-portal wiring, the Beoordelen user task)
+
+## Context
+
+S-11 lets a zorgprofessional withdraw a still-open registration ("trek aanvraag in"). S-11a already
+advances the aggregate to INGETROKKEN (domain state). But the registratie process is still running in
+Flowable — parked at the `Beoordelen` user task — so without a second step the withdrawn registration
+would linger as work for a behandelaar. The withdrawal must also **cancel the running process**.
+
+Two questions shape this sub-slice.
+
+1. **How does the case get cancelled — in code, or in the BPMN model?**
+2. **How does a withdrawal correlate to the right running process instance?**
+
+## Decision
+
+**The BPMN models the cancellation as an interrupting message boundary event on the `Beoordelen`
+task; the Workflow Client correlates a `RegistratieIngetrokken` message to the task's execution.**
+
+- **Modelled in BPMN, not deleted from code.** The `Beoordelen` user task carries an interrupting
+  message boundary event (`RegistratieIngetrokken`) that routes to a dedicated "Registratie
+  ingetrokken" end event. The process's own model says *how* a withdrawal ends it — the Workflow
+  Client only delivers the message; it never reaches into Flowable to delete an instance. This keeps
+  the workflow's control flow in the workflow (§8.2) and leaves an audit trail in Flowable history
+  (the process ended via the ingetrokken path, not a raw delete).
+- **Correlated by the registration's own process instance.** The aggregate records its Flowable
+  process instance id at submit, so the `WithdrawRegistration` handler correlates directly by that
+  id — no task lookup. The Workflow Client asks Flowable for the execution **subscribed to** the
+  `RegistratieIngetrokken` message in that instance and delivers `messageEventReceived` to it.
+  Targeting the subscribed execution (not the user task's execution — a message boundary event's
+  subscription lives on its own execution) is what makes the correlation land.
+- **Best-effort, mirroring the beoordeling.** If no open `Beoordelen` task is found (the process has
+  not yet parked there — the `OpenZaakAanmaken` window — or has already ended), the withdrawal still
+  stands: the aggregate is INGETROKKEN and the werkbak filters it out regardless (S-11b). We complete
+  the domain transition first and cancel the workflow best-effort, exactly as `BeoordeelRegistratie`
+  completes its task best-effort.
+
+## Consequences
+
+**Positive**
+
+- The cancellation path is visible in `registratie.bpmn`; the Workflow Client stays the only code
+  that talks to Flowable and does not delete instances behind the model's back.
+- Reuses the existing task-query correlation — no new plumbing, no correlation store.
+- A withdrawn case leaves the werkbak (its `Beoordelen` task is cancelled), and the werkbak also
+  filters non-open registrations as a belt-and-braces for the brief window before cancellation lands.
+
+**Negative / costs**
+
+- A withdrawal raced ahead of the process reaching `Beoordelen` (during `OpenZaakAanmaken`, seconds)
+  finds no task to cancel, so that process instance runs on to `Beoordelen` and parks there with no
+  one to act on it (it is hidden from the werkbak by the status filter). Acceptable for this
+  reference at these volumes; a process-level interrupting event subprocess would close the gap and
+  is an additive follow-up if it matters.
+- The Flowable message-correlation REST shape is validated live (verify-stack), not in the
+  Workflow Client's unit tests, which stub the HTTP exchange and assert only the request shape
+  (consistent with ADR-0009).
+
+## Alternatives considered
+
+- **Delete the process instance from the Workflow Client** (`DELETE /runtime/process-instances/{id}`)
+  — rejected: it cancels the case but hides the reason from the BPMN model; the "why" lives in code,
+  not the process. The message event keeps the cancellation a first-class part of the workflow.
+- **Interrupting message event subprocess at process level** — more robust (correlates anytime,
+  closing the `OpenZaakAanmaken`-race gap), but a heavier BPMN construct; deferred as an additive
+  change if the race proves to matter.

docs/demo-script.md

@@ -248,3 +248,30 @@ curl -fsS "http://localhost:8140/openbaar/register?q=$ref" | jq
 
 > 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.
+
+## S-12 — Behandel portal: werkbak + beoordeling (#13, ADR-0013)
+
+A behandelaar now works submitted registrations in a real portal instead of the temporary admin
+endpoint. After a citizen submits (as above), the workflow parks the registration at the Flowable
+`Beoordelen` user task, and it shows up in the **werkbak**. The behandelaar logs in against the
+Keycloak `medewerker` realm and decides — **goedkeuren** (→ INGESCHREVEN via the ACL, per ADR-0011)
+or **afwijzen** — which also completes the Beoordelen task so the process advances.
+
+```text
+# 1. Open the behandel portal and log in as a behandelaar (medewerker realm):
+#    http://localhost:8142/   →  merel-behandelaar / test123
+#
+# 2. The werkbak lists the registrations awaiting beoordeling (referentie / bsn / status).
+#    Find the reference from the submit confirmation and click "Goedkeuren" on that row.
+#
+# 3. The row drops off the werkbak (its Beoordelen task is completed) and the openbaar register
+#    (http://localhost:8141/) now shows that reference as INGESCHREVEN.
+```
+
+**The path:** behandel portal → BFF `POST /behandel/registrations/{id}/decide` (behandelaar policy,
+`medewerker` realm) → domain applies the decision + completes the Flowable `Beoordelen` task →
+ACL → NRC → event-subscriber → projection → openbaar register shows INGESCHREVEN.
+
+> The full round-trip — DigiD submit → public INGEDIEND → behandelaar goedkeurt in the werkbak →
+> public INGESCHREVEN — is the Playwright happy path (`tests/e2e/registration.spec.ts`), which now
+> drives the behandel portal in place of the old admin endpoint.

docs/frontend-decisions.md

@@ -117,3 +117,37 @@ with the submit form (S-08c, #67); any deviation from NL DS will be recorded her
   (id + status); `bsn`/`naam` never leave the BFF. The e2e asserts the bsn never renders.
 - **Loads on open, filters on search.** `RegisterPage` fetches the full register on construction and
   re-queries `/openbaar/register?q=` on search — no client-side filtering, the BFF owns the query.
+
+## Behandel portal (S-12, #13)
+
+The staff portal where a behandelaar works the **werkbak** (registrations awaiting beoordeling) and
+decides each — goedkeuren or afwijzen. `apps/behandel` mirrors `apps/self-service`; the net-new
+frontend work is the medewerker realm auth and the werkbak/decide page. Wiring rationale is in
+**ADR-0013**; this entry records the frontend-specific choices.
+
+- **Medewerker realm auth, reusing `libs/auth`.** Staff authenticate against the Keycloak
+  `medewerker` realm (public client `big-portal`), not `digid`. Rather than fork the auth lib, the
+  abstract `AuthService` grew a **`roles`/`hasRole` surface** (empty for realms without roles, e.g.
+  `digid`), and a parallel **`MedewerkerAuthService` + `provideMedewerkerAuth`** were added — same
+  auth-code + PKCE config, bound to the medewerker realm, reading the nested `realm_access.roles`
+  claim. The library's own `authInterceptor` attaches the token to the relative `/behandel/` calls
+  (secure route), exactly as self-service does for `/self-service/`.
+- **Roles reach the frontend via a realm mapper.** Keycloak emits realm roles in the access token by
+  default but not the ID token/userinfo the SPA reads, so the medewerker `big-portal` client gets a
+  **realm-roles protocol mapper** (`realm_access.roles`, added to id + userinfo tokens). The
+  **BFF remains the security boundary** (`behandelaar` policy, 401/403 on `/behandel/*`, ADR-0013);
+  the frontend role signal is for display/UX, and the werkbak page surfaces a load failure (e.g. a
+  403 for a non-behandelaar) rather than swallowing it.
+- **Same-origin via nginx, like the other portals.** The compose `behandel` image serves the built
+  app and reverse-proxies `/behandel` to the BFF (relative calls, no CORS). Served on `:8142`,
+  health-checked over IPv4 (`127.0.0.1`), depends on Keycloak for the medewerker realm.
+- **Werkbak = decide-and-refresh.** `WerkbakPage` loads `GET /behandel/werkbak` on open and renders a
+  row per registration (referentie/bsn/status). Goedkeuren/afwijzen `POST /behandel/registrations/
+  {id}/decide` and then reload the werkbak, so the handled item drops off (its Flowable `Beoordelen`
+  task is completed). Per-row decide buttons carry an `aria-label` including the reference, so the
+  e2e (and screen readers) can target a specific registration in a shared werkbak.
+- **Testing.** Component tests use `@testing-library/angular` with `BffApiV1Service`/`AuthService`
+  mocked and the axe WCAG 2.1 AA check; an `app.config.spec` drives the real interceptor + api-client
+  to assert the medewerker token attaches to `/behandel/*` (and not to the anonymous openbaar call).
+  The full DigiD-submit → behandel-decide → public INGESCHREVEN round-trip is the Playwright happy
+  path.

infra/docker-compose.local.yml

@@ -17,7 +17,12 @@
 #
 # Port map (host):
 #   8000 OpenZaak · 8001 Open Notificaties · 8080 BFF · 8090 Flowable REST
-#   8100 ACL · 8180 Keycloak   (all admin: admin / admin — dev only)
+#   8100 ACL · 8130 Domain · 8180 Keycloak   (all admin: admin / admin — dev only)
+#   8140 self-service portal · 8141 openbaar register · 8142 behandel portal
+#
+# Portal OIDC on the HOST: browse the portals at their 8140/8141/8142 ports and log in via
+# Keycloak on localhost:8180 (KC_HOSTNAME below pins the issuer there; the BFF still validates
+# in-network via keycloak:8080). Test users are in docs/synthetic-data.md.
 
 services:
 
@@ -205,6 +210,12 @@ services:
       KEYCLOAK_ADMIN_PASSWORD: admin
       KC_HEALTH_ENABLED: "true"
       KC_HTTP_ENABLED: "true"
+      # Pin the frontend/issuer URL to the host-published address so a browser on the host and the
+      # tokens it gets both use localhost:8180. KC_HOSTNAME_BACKCHANNEL_DYNAMIC lets in-network
+      # callers (the BFF via keycloak:8080) still resolve token/jwks endpoints to their request host,
+      # so the BFF validates the localhost:8180 issuer while fetching keys over the compose network.
+      KC_HOSTNAME: http://localhost:8180
+      KC_HOSTNAME_BACKCHANNEL_DYNAMIC: "true"
     ports:
       - "8180:8080"
     volumes:
@@ -295,6 +306,14 @@ services:
       context: ../services/bff
       dockerfile: Dockerfile
     image: register-referentie/bff:dev
+    environment:
+      # Reach Keycloak over the compose network for metadata/keys; the discovered issuer is the
+      # host-pinned localhost:8180 (KC_HOSTNAME above), which is what browser tokens carry — so
+      # validation matches without the BFF ever needing to resolve localhost:8180 itself.
+      Keycloak__Authority: http://keycloak:8080/realms/digid
+      Keycloak__MedewerkerAuthority: http://keycloak:8080/realms/medewerker
+      Downstream__Domain__BaseUrl: http://domain:8080/
+      Downstream__Projection__BaseUrl: http://projection-api:8080/
     ports:
       - "8080:8080"
     healthcheck:
@@ -303,6 +322,39 @@ services:
       timeout: 3s
       retries: 5
       start_period: 10s
+    depends_on:
+      domain:
+        condition: service_healthy
+      projection-api:
+        condition: service_healthy
+      keycloak:
+        condition: service_started
+    networks: [cg]
+
+  # ── BIG Domain Service (S-05) ─────────────────────────────────────────────
+  domain:
+    build:
+      context: ../services/domain
+      dockerfile: Dockerfile
+    image: register-referentie/domain:dev
+    environment:
+      Flowable__BaseUrl: http://flowable-rest:8080/flowable-rest/
+      Flowable__Username: rest-admin
+      Flowable__Password: test
+      Acl__BaseUrl: http://acl:8080/
+    ports:
+      - "8130:8080"
+    healthcheck:
+      test: ["CMD", "curl", "-fsS", "http://localhost:8080/health"]
+      interval: 5s
+      timeout: 3s
+      retries: 5
+      start_period: 10s
+    depends_on:
+      acl:
+        condition: service_healthy
+      flowable-init:
+        condition: service_completed_successfully
     networks: [cg]
 
   # ── Read projection (S-06) ────────────────────────────────────────────────
@@ -362,6 +414,73 @@ services:
         condition: service_healthy
     networks: [cg]
 
+  # ── Portals (S-08/S-09/S-12) ──────────────────────────────────────────────
+  # nginx serves each Angular app and reverse-proxies its endpoint group to the BFF (same-origin).
+  # The images bake config.json with the compose authority (keycloak:8080), which a HOST browser
+  # can't resolve — so here we bind-mount a config.json pointing at the host-published localhost:8180
+  # (matching KC_HOSTNAME). openbaar is anonymous and needs no config.
+  self-service:
+    build:
+      context: ..
+      dockerfile: apps/self-service/Dockerfile
+    image: register-referentie/self-service:dev
+    ports:
+      - "8140:80"
+    volumes:
+      - ./local-config/self-service.config.json:/usr/share/nginx/html/config.json:ro,z
+    healthcheck:
+      test: ["CMD-SHELL", "wget -q -O /dev/null http://127.0.0.1/ || exit 1"]
+      interval: 5s
+      timeout: 3s
+      retries: 5
+      start_period: 10s
+    depends_on:
+      bff:
+        condition: service_healthy
+      keycloak:
+        condition: service_started
+    networks: [cg]
+
+  openbaar:
+    build:
+      context: ..
+      dockerfile: apps/openbaar/Dockerfile
+    image: register-referentie/openbaar:dev
+    ports:
+      - "8141:80"
+    healthcheck:
+      test: ["CMD-SHELL", "wget -q -O /dev/null http://127.0.0.1/ || exit 1"]
+      interval: 5s
+      timeout: 3s
+      retries: 5
+      start_period: 10s
+    depends_on:
+      bff:
+        condition: service_healthy
+    networks: [cg]
+
+  behandel:
+    build:
+      context: ..
+      dockerfile: apps/behandel/Dockerfile
+    image: register-referentie/behandel:dev
+    ports:
+      - "8142:80"
+    volumes:
+      - ./local-config/behandel.config.json:/usr/share/nginx/html/config.json:ro,z
+    healthcheck:
+      test: ["CMD-SHELL", "wget -q -O /dev/null http://127.0.0.1/ || exit 1"]
+      interval: 5s
+      timeout: 3s
+      retries: 5
+      start_period: 10s
+    depends_on:
+      bff:
+        condition: service_healthy
+      keycloak:
+        condition: service_started
+    networks: [cg]
+
 volumes:
   oz-db:
   nrc-db:

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:
@@ -484,6 +486,29 @@ services:
         condition: service_healthy
     networks: [cg]
 
+  # The behandel portal: nginx serves the Angular app and reverse-proxies /behandel to the BFF.
+  # Behandelaars log in against the Keycloak medewerker realm (ADR-0013; S-12).
+  behandel:
+    build:
+      context: ..
+      dockerfile: apps/behandel/Dockerfile
+    image: register-referentie/behandel:dev
+    ports:
+      - "8142:80"
+    healthcheck:
+      # 127.0.0.1, not localhost: nginx listens on IPv4 only, but localhost resolves to ::1 first.
+      test: ["CMD-SHELL", "wget -q -O /dev/null http://127.0.0.1/ || exit 1"]
+      interval: 5s
+      timeout: 3s
+      retries: 5
+      start_period: 10s
+    depends_on:
+      bff:
+        condition: service_healthy
+      keycloak:
+        condition: service_started
+    networks: [cg]
+
 volumes:
   oz-db:
   nrc-db:

infra/keycloak/realms/medewerker-realm.json

@@ -16,7 +16,22 @@
       "standardFlowEnabled": true,
       "directAccessGrantsEnabled": true,
       "redirectUris": ["*"],
-      "webOrigins": ["*"]
+      "webOrigins": ["*"],
+      "protocolMappers": [
+        {
+          "name": "realm roles",
+          "protocol": "openid-connect",
+          "protocolMapper": "oidc-usermodel-realm-role-mapper",
+          "config": {
+            "multivalued": "true",
+            "claim.name": "realm_access.roles",
+            "jsonType.label": "String",
+            "id.token.claim": "true",
+            "access.token.claim": "true",
+            "userinfo.token.claim": "true"
+          }
+        }
+      ]
     }
   ],
   "users": [

infra/local-config/behandel.config.json

@@ -0,0 +1,3 @@
+{
+  "authority": "http://localhost:8180/realms/medewerker"
+}

infra/local-config/self-service.config.json

@@ -0,0 +1,3 @@
+{
+  "authority": "http://localhost:8180/realms/digid"
+}

infra/run-domain-check.sh

@@ -79,9 +79,9 @@ fl="$(docker ps -q --filter 'name=flowable-rest' | head -1)"
 fl_base="http://$(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.
+# Extracts the Beoordelen task id for a given registration from a Flowable task-query response on
-# Tolerates an empty/non-JSON body (a transient failure during the poll) by printing nothing.
+# 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
+task_for_reg() { REG_ID="$1" python3 -c "import os,sys,json
 try:
     d=json.load(sys.stdin)
 except Exception:
@@ -98,7 +98,7 @@ 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)"
+  task_id="$(printf '%s' "$resp" | task_for_reg "$reg_id")"
   [ -n "$task_id" ] && break
   sleep 2
 done
@@ -115,7 +115,46 @@ flcurl -X POST "$fl_base/runtime/tasks/$task_id" -H 'Content-Type: application/j
 
 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' "$resp" | task_for_reg)"
+still="$(printf '%s' "$resp" | task_for_reg "$reg_id")"
 [ -z "$still" ] || { echo "FAIL — Beoordelen task $still still active after completion" >&2; exit 1; }
 echo "OK — behandelaar claimed and completed the Beoordelen task; the registratie process finished"
+
+# ── S-11: withdrawal. A second registration parks at Beoordelen; the citizen withdraws it via the
+# domain, which delivers the RegistratieIngetrokken message to the task's execution, tripping the
+# BPMN boundary event so the process ends and the Beoordelen task disappears (ADR-0014). ────────────
+echo ">> submitting a second registration to withdraw"
+loc2="$(docker run --rm --network "$net" curlimages/curl:latest \
+  -fsS -D - -o /dev/null -X POST "http://$dom_ip:8080/registrations" \
+  -H 'Content-Type: application/json' -d '{"bsn":"123456782"}' \
+  | sed -n 's/\r$//; s/^[Ll]ocation: //p' | head -1)"
+[ -n "$loc2" ] || { echo "FAIL — second POST /registrations returned no Location" >&2; exit 1; }
+reg_id2="${loc2##*/}"
+echo ">> second registration $reg_id2"
+
+echo ">> polling Flowable for its Beoordelen task"
+task_id2=""
+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_id2="$(printf '%s' "$resp" | task_for_reg "$reg_id2")"
+  [ -n "$task_id2" ] && break
+  sleep 2
+done
+[ -n "$task_id2" ] || { echo "FAIL — no Beoordelen task appeared for registration $reg_id2" >&2; docker logs "$dom" 2>&1 | tail -15 >&2; exit 1; }
+echo ">> Beoordelen task $task_id2 is waiting; withdrawing the registration via the domain"
+
+# Owner-scoped: the withdraw carries the same bsn the registration was submitted with (S-11c).
+docker run --rm --network "$net" curlimages/curl:latest \
+  -fsS -X POST "http://$dom_ip:8080/registrations/$reg_id2/withdraw" \
+  -H 'Content-Type: application/json' -d '{"bsn":"123456782"}' >/dev/null
+
+echo ">> asserting the process was cancelled (no Beoordelen task remains for the registration)"
+gone=""
+for _ in $(seq 1 15); do
+  resp="$(flcurl -X POST "$fl_base/query/tasks" -H 'Content-Type: application/json' -d "$query" 2>/dev/null || true)"
+  still2="$(printf '%s' "$resp" | task_for_reg "$reg_id2")"
+  [ -z "$still2" ] && { gone=1; break; }
+  sleep 2
+done
+[ -n "$gone" ] || { echo "FAIL — Beoordelen task for $reg_id2 still active after withdrawal" >&2; docker logs "$dom" 2>&1 | tail -15 >&2; exit 1; }
+echo "OK — withdrawal cancelled the Beoordelen task; the registratie process ended (ingetrokken)"
 exit 0

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

@@ -24,6 +24,10 @@ import {
   Observable
 } from 'rxjs';
 
+export interface DecideRequest {
+  besluit: string;
+}
+
 export interface OpenbaarEntry {
   id: string;
   status: string;
@@ -36,6 +40,12 @@ export interface SubmitAccepted {
   status: string;
 }
 
+export interface WerkbakItem {
+  registrationId: string;
+  bsn: string;
+  status: string;
+}
+
 export type GetOpenbaarRegisterParams = {
 q?: string;
 };
@@ -182,6 +192,40 @@ export class BffApiV1Service {
     );
   }
 
+ postSelfServiceRegistrationsIdWithdraw<TData = void>(id: string, options?: HttpClientBodyOptions): Observable<TData>;
+ postSelfServiceRegistrationsIdWithdraw<TData = void>(id: string, options?: HttpClientEventOptions): Observable<HttpEvent<TData>>;
+ postSelfServiceRegistrationsIdWithdraw<TData = void>(id: string, options?: HttpClientResponseOptions): Observable<AngularHttpResponse<TData>>;
+  postSelfServiceRegistrationsIdWithdraw<TData = void>(
+    id: string, options?: HttpClientObserveOptions): Observable<TData | HttpEvent<TData> | AngularHttpResponse<TData>> {
+    if (options?.observe === 'events') {
+      return this.http.post<TData>(
+      `/self-service/registrations/${id}/withdraw`,
+      undefined,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'events',
+      }
+    );
+    }
+
+    if (options?.observe === 'response') {
+      return this.http.post<TData>(
+      `/self-service/registrations/${id}/withdraw`,
+      undefined,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'response',
+      }
+    );
+    }
+
+    return this.http.post<TData>(
+      `/self-service/registrations/${id}/withdraw`,
+      undefined,{
+        ...(options as Omit<NonNullable<typeof options>, 'observe'>),
+        observe: 'body',
+      }
+    );
+  }
+
  getOpenbaarRegister<TData = OpenbaarEntry[]>(params?: GetOpenbaarRegisterParams, options?: HttpClientBodyOptions): Observable<TData>;
  getOpenbaarRegister<TData = OpenbaarEntry[]>(params?: GetOpenbaarRegisterParams, options?: HttpClientEventOptions): Observable<HttpEvent<TData>>;
  getOpenbaarRegister<TData = OpenbaarEntry[]>(params?: GetOpenbaarRegisterParams, options?: HttpClientResponseOptions): Observable<AngularHttpResponse<TData>>;
@@ -215,4 +259,73 @@ 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',
+      }
+    );
+  }
+
 };

libs/auth/src/index.ts

@@ -1,4 +1,6 @@
 export * from './lib/auth.service';
 export * from './lib/digid-auth.service';
 export * from './lib/digid-auth.providers';
+export * from './lib/medewerker-auth.service';
+export * from './lib/medewerker-auth.providers';
 export * from './lib/authenticated.guard';

libs/auth/src/lib/auth.service.ts

@@ -1,16 +1,26 @@
-import { Signal } from '@angular/core';
+import { signal, Signal } from '@angular/core';
 
 /**
  * The portal's view of the signed-in user. An abstraction over the OIDC library so components and
- * guards depend on a small, mockable surface (the real implementation is DigiadAuthService).
+ * guards depend on a small, mockable surface (the real implementations are DigiadAuthService for
+ * citizens and MedewerkerAuthService for staff).
  */
 export abstract class AuthService {
-  /** Whether a DigiD session is active. */
+  /** Whether a session is active. */
   abstract readonly isAuthenticated: Signal<boolean>;
-  /** The citizen-service number from the DigiD token, once authenticated. */
+  /** The citizen-service number from the DigiD token, once authenticated (staff have none). */
   abstract readonly bsn: Signal<string | undefined>;
-  /** Start the DigiD login (redirects to Keycloak). */
+  /**
+   * The realm roles carried in the token. Empty for realms that don't grant roles (e.g. `digid`);
+   * the `medewerker` realm carries `behandelaar`/`teamlead`.
+   */
+  readonly roles: Signal<readonly string[]> = signal<readonly string[]>([]);
+  /** Start login (redirects to Keycloak). */
   abstract login(): void;
   /** End the session. */
   abstract logout(): void;
+  /** Whether the signed-in user holds the given realm role. */
+  hasRole(role: string): boolean {
+    return this.roles().includes(role);
+  }
 }

libs/auth/src/lib/medewerker-auth.providers.ts

@@ -0,0 +1,49 @@
+import { EnvironmentProviders, makeEnvironmentProviders } from '@angular/core';
+import { LogLevel, provideAuth, withAppInitializerAuthCheck } from 'angular-auth-oidc-client';
+import { AuthService } from './auth.service';
+import { MedewerkerAuthService } from './medewerker-auth.service';
+
+export interface MedewerkerAuthOptions {
+  /** The Keycloak `medewerker` realm issuer, as reachable from the browser. */
+  authority: string;
+  /** Where Keycloak redirects back to after login (usually the app origin). */
+  redirectUrl: string;
+  /**
+   * Route prefixes whose requests get the bearer token attached. The api-client calls the BFF with
+   * **relative** URLs (same-origin via the nginx proxy), so these must be relative path prefixes
+   * (e.g. `/behandel/`) — angular-auth-oidc-client matches `req.url.startsWith(route)`, and a
+   * relative `req.url` never starts with an absolute origin.
+   */
+  secureRoutes: string[];
+}
+
+/**
+ * Configure medewerker login (Keycloak `medewerker` realm, public client `big-portal`, auth-code +
+ * PKCE) and bind {@link AuthService} to the medewerker-backed implementation. Register
+ * {@link authInterceptor} (re-exported from digid-auth.providers) in the app's HttpClient so BFF
+ * calls carry the token.
+ */
+export function provideMedewerkerAuth(options: MedewerkerAuthOptions): EnvironmentProviders {
+  return makeEnvironmentProviders([
+    provideAuth(
+      {
+        config: {
+          authority: options.authority,
+          redirectUrl: options.redirectUrl,
+          postLogoutRedirectUri: options.redirectUrl,
+          clientId: 'big-portal',
+          scope: 'openid profile',
+          responseType: 'code',
+          silentRenew: true,
+          useRefreshToken: true,
+          secureRoutes: options.secureRoutes,
+          logLevel: LogLevel.Warn,
+        },
+      },
+      // Run checkAuth() at startup so the login callback (?code=…) is processed before the router
+      // and guard run — without it the guard sees "not authenticated" and re-triggers login (loop).
+      withAppInitializerAuthCheck(),
+    ),
+    { provide: AuthService, useClass: MedewerkerAuthService },
+  ]);
+}

libs/auth/src/lib/medewerker-auth.service.spec.ts

@@ -0,0 +1,43 @@
+import { TestBed } from '@angular/core/testing';
+import { OidcSecurityService } from 'angular-auth-oidc-client';
+import { of } from 'rxjs';
+import { MedewerkerAuthService } from './medewerker-auth.service';
+
+function makeService(userData: unknown, authenticated = true) {
+  const oidc = {
+    isAuthenticated$: of({ isAuthenticated: authenticated }),
+    userData$: of({ userData }),
+    authorize: vi.fn(),
+    logoff: vi.fn(() => of(null)),
+  };
+  TestBed.configureTestingModule({
+    providers: [MedewerkerAuthService, { provide: OidcSecurityService, useValue: oidc }],
+  });
+  return { svc: TestBed.inject(MedewerkerAuthService), oidc };
+}
+
+describe('MedewerkerAuthService', () => {
+  it('exposes the realm roles carried in the token', () => {
+    const { svc } = makeService({ realm_access: { roles: ['behandelaar', 'teamlead'] } });
+    expect(svc.roles()).toEqual(['behandelaar', 'teamlead']);
+    expect(svc.hasRole('behandelaar')).toBe(true);
+    expect(svc.hasRole('beheerder')).toBe(false);
+  });
+
+  it('has no roles when the token omits realm_access', () => {
+    const { svc } = makeService({ preferred_username: 'merel-behandelaar' });
+    expect(svc.roles()).toEqual([]);
+    expect(svc.hasRole('behandelaar')).toBe(false);
+  });
+
+  it('reflects the OIDC authenticated state', () => {
+    const { svc } = makeService({}, true);
+    expect(svc.isAuthenticated()).toBe(true);
+  });
+
+  it('starts login by delegating to the OIDC library', () => {
+    const { svc, oidc } = makeService({});
+    svc.login();
+    expect(oidc.authorize).toHaveBeenCalledTimes(1);
+  });
+});

libs/auth/src/lib/medewerker-auth.service.ts

@@ -0,0 +1,41 @@
+import { inject, Injectable, Signal } from '@angular/core';
+import { toSignal } from '@angular/core/rxjs-interop';
+import { OidcSecurityService } from 'angular-auth-oidc-client';
+import { map } from 'rxjs';
+import { AuthService } from './auth.service';
+
+/** The subset of the medewerker token the portal reads: Keycloak nests realm roles here. */
+interface MedewerkerClaims {
+  realm_access?: { roles?: string[] };
+}
+
+/** Medewerker-backed AuthService over angular-auth-oidc-client (Keycloak `medewerker` realm). */
+@Injectable()
+export class MedewerkerAuthService extends AuthService {
+  private readonly oidc = inject(OidcSecurityService);
+
+  readonly isAuthenticated: Signal<boolean> = toSignal(
+    this.oidc.isAuthenticated$.pipe(map((result) => result.isAuthenticated)),
+    { initialValue: false },
+  );
+
+  // Staff have no BSN; the abstract surface keeps this present for the shared guard/interceptor.
+  readonly bsn: Signal<string | undefined> = toSignal(this.oidc.userData$.pipe(map(() => undefined)), {
+    initialValue: undefined,
+  });
+
+  override readonly roles: Signal<readonly string[]> = toSignal(
+    this.oidc.userData$.pipe(
+      map((data) => (data.userData as MedewerkerClaims | null)?.realm_access?.roles ?? []),
+    ),
+    { initialValue: [] },
+  );
+
+  override login(): void {
+    this.oidc.authorize();
+  }
+
+  override logout(): void {
+    this.oidc.logoff().subscribe();
+  }
+}

services/bff/Bff.Api/DownstreamClients.cs

@@ -13,10 +13,25 @@ public sealed record ProjectionEntry(string Id, string Status, string? Reference
 /// <summary>A public-safe openbaar register row — only non-sensitive fields leave the BFF.</summary>
 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>Withdraw the caller's own registration ("trek aanvraag in"). Owner-scoped by
+    /// <paramref name="bsn"/>. Returns <c>false</c> when the domain reports the registration is
+    /// unknown or not the caller's (404), so the BFF can relay a 404 rather than a 500.</summary>
+    Task<bool> WithdrawRegistrationAsync(string registrationId, 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>
@@ -37,6 +52,27 @@ public sealed class DomainClient(HttpClient http) : IDomainClient
         return new SubmitAccepted(dto.RegistrationId, dto.Status);
     }
 
+    public async Task<bool> WithdrawRegistrationAsync(string registrationId, string bsn, CancellationToken ct = default)
+    {
+        using var response = await http.PostAsJsonAsync(
+            $"registrations/{registrationId}/withdraw", new { bsn }, ct);
+        // The domain 404s an unknown or not-owned registration; relay that rather than fail hard.
+        if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
+            return false;
+        response.EnsureSuccessStatusCode();
+        return true;
+    }
+
+    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/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));
@@ -60,6 +86,24 @@ app.MapPost("/self-service/registrations", async (ClaimsPrincipal user, IDomainC
     .Produces(StatusCodes.Status400BadRequest)
     .Produces(StatusCodes.Status401Unauthorized);
 
+// Self-service withdrawal (S-11): the signed-in zorgprofessional withdraws their own registration.
+// The bsn comes from the DigiD token and is forwarded to the domain, which owner-scopes the action;
+// a registration that is unknown or not the caller's comes back 404 (ownership is not revealed).
+app.MapPost("/self-service/registrations/{id}/withdraw", async (string id, ClaimsPrincipal user, IDomainClient domain, CancellationToken ct) =>
+{
+    var bsn = user.FindFirstValue("bsn");
+    if (string.IsNullOrWhiteSpace(bsn))
+        return Results.BadRequest("The token carries no bsn claim.");
+
+    var withdrawn = await domain.WithdrawRegistrationAsync(id, bsn, ct);
+    return withdrawn ? Results.NoContent() : Results.NotFound();
+})
+    .RequireAuthorization()
+    .Produces(StatusCodes.Status204NoContent)
+    .Produces(StatusCodes.Status400BadRequest)
+    .Produces(StatusCodes.Status401Unauthorized)
+    .Produces(StatusCodes.Status404NotFound);
+
 // Openbaar register: an anonymous public lookup that exposes only public-safe fields (S-09).
 app.MapGet("/openbaar/register", async (string? q, IProjectionClient projection, CancellationToken ct) =>
 {
@@ -68,7 +112,79 @@ 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;
 
@@ -23,9 +24,34 @@ internal sealed class BffFactory : WebApplicationFactory<Program>
     public FakeDomainClient Domain { get; } = new();
     public FakeProjectionClient Projection { get; } = new();
 
+    private static void ValidateWithTestKey(IServiceCollection services, string scheme) =>
+        services.Configure<JwtBearerOptions>(scheme, options =>
+        {
+            // Validate locally against the test key and NEVER reach out for OIDC metadata. A static
+            // configuration manager guarantees this regardless of Configure/PostConfigure ordering —
+            // clearing Authority alone left the medewerker scheme fetching metadata under CI timing
+            // (2s hang → 401), because JwtBearer's PostConfigure could still build a ConfigurationManager.
+            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,
+                ValidateAudience = false,
+                ValidateLifetime = true,
+                ValidateIssuerSigningKey = true,
+                IssuerSigningKey = TestSigningKey,
+                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/");
 
@@ -34,23 +60,11 @@ internal sealed class BffFactory : WebApplicationFactory<Program>
             services.AddSingleton<IDomainClient>(Domain);
             services.AddSingleton<IProjectionClient>(Projection);
 
-            services.Configure<JwtBearerOptions>(JwtBearerDefaults.AuthenticationScheme, options =>
+            // 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
-                // Validate locally against the test key; never reach out for OIDC metadata.
+            // parameters are swapped here.
-                options.Authority = null;
+            ValidateWithTestKey(services, JwtBearerDefaults.AuthenticationScheme);
-                options.MetadataAddress = null!;
+            ValidateWithTestKey(services, "medewerker");
-                options.RequireHttpsMetadata = false;
-                options.Configuration = new OpenIdConnectConfiguration();
-                options.TokenValidationParameters = new TokenValidationParameters
-                {
-                    ValidateIssuer = false,
-                    ValidateAudience = false,
-                    ValidateLifetime = true,
-                    ValidateIssuerSigningKey = true,
-                    IssuerSigningKey = TestSigningKey,
-                    ClockSkew = TimeSpan.Zero,
-                };
-            });
         });
     }
 }
@@ -60,12 +74,36 @@ 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 Bsn)? Withdrawn { get; private set; }
+
+    /// <summary>Whether the fake domain reports the withdrawal as done (true → 204) or not-found/not-owned
+    /// (false → 404). Tests set this to exercise the relay.</summary>
+    public bool WithdrawSucceeds { get; set; } = true;
+
+    public Task<bool> WithdrawRegistrationAsync(string registrationId, string bsn, CancellationToken ct = default)
+    {
+        Withdrawn = (registrationId, bsn);
+        return Task.FromResult(WithdrawSucceeds);
+    }
+
+    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/SelfServiceEndpointTests.cs

@@ -71,5 +71,46 @@ public class SelfServiceEndpointTests
         Assert.Equal("reg-123", body!.RegistrationId);
     }
 
+    private static HttpRequestMessage Withdraw(string? bearer, string id = "reg-123")
+    {
+        var request = new HttpRequestMessage(HttpMethod.Post, $"/self-service/registrations/{id}/withdraw");
+        if (bearer is not null)
+            request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", bearer);
+        return request;
+    }
+
+    [Fact]
+    public async Task Rejects_a_withdrawal_without_a_token()
+    {
+        using var factory = new BffFactory();
+
+        var response = await factory.CreateClient().SendAsync(Withdraw(bearer: null));
+
+        Assert.Equal(HttpStatusCode.Unauthorized, response.StatusCode);
+        Assert.Null(factory.Domain.Withdrawn);
+    }
+
+    [Fact]
+    public async Task Withdraws_the_callers_registration_forwarding_the_id_and_bsn()
+    {
+        using var factory = new BffFactory();
+
+        var response = await factory.CreateClient().SendAsync(Withdraw(TestTokens.Valid("123456782"), "reg-9"));
+
+        Assert.Equal(HttpStatusCode.NoContent, response.StatusCode);
+        Assert.Equal(("reg-9", "123456782"), factory.Domain.Withdrawn);
+    }
+
+    [Fact]
+    public async Task Relays_not_found_when_the_registration_is_unknown_or_not_the_callers()
+    {
+        using var factory = new BffFactory();
+        factory.Domain.WithdrawSucceeds = false;
+
+        var response = await factory.CreateClient().SendAsync(Withdraw(TestTokens.Valid("123456782")));
+
+        Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
+    }
+
     private sealed record SubmitAcceptedDto(string RegistrationId, string Status);
 }

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

@@ -30,6 +30,37 @@
         }
       }
     },
+    "/self-service/registrations/{id}/withdraw": {
+      "post": {
+        "tags": [
+          "Bff.Api"
+        ],
+        "parameters": [
+          {
+            "name": "id",
+            "in": "path",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          }
+        ],
+        "responses": {
+          "204": {
+            "description": "No Content"
+          },
+          "400": {
+            "description": "Bad Request"
+          },
+          "401": {
+            "description": "Unauthorized"
+          },
+          "404": {
+            "description": "Not Found"
+          }
+        }
+      }
+    },
     "/openbaar/register": {
       "get": {
         "tags": [
@@ -60,10 +91,90 @@
           }
         }
       }
+    },
+    "/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",
@@ -100,6 +211,25 @@
             "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

@@ -26,6 +26,8 @@ builder.Services.AddHttpClient<IAclClient, AclHttpClient>();
 builder.Services.AddScoped<SubmitRegistration>();
 builder.Services.AddScoped<ApproveRegistration>();
 builder.Services.AddScoped<BeoordeelRegistratie>();
+builder.Services.AddScoped<WithdrawRegistration>();
+builder.Services.AddScoped<Werkbak>();
 builder.Services.AddScoped<OpenZaakWorker>();
 builder.Services.AddScoped<OpenZaakJobProcessor>();
 
@@ -73,6 +75,28 @@ app.MapPost("/registrations/{id}/decide", async (string id, DecideRequest body,
     return Results.NoContent();
 });
 
+// Withdraw a registration (S-11): the zorgprofessional pulls their own still-open submission back,
+// advancing it to INGETROKKEN and cancelling its workflow. Owner-scoped by the caller's bsn (the BFF
+// forwards it from the DigiD token, S-11c); a registration that is unknown or not the caller's is
+// 404 (indistinguishable, so ownership isn't leaked). Idempotent.
+app.MapPost("/registrations/{id}/withdraw", async (string id, WithdrawRequest body, WithdrawRegistration withdraw, CancellationToken ct) =>
+{
+    if (!Guid.TryParse(id, out var guid))
+        return Results.NotFound();
+
+    if (string.IsNullOrWhiteSpace(body?.Bsn))
+        return Results.BadRequest(new { error = "A bsn is required to withdraw a registration." });
+
+    var outcome = await withdraw.HandleAsync(new WithdrawRegistrationCommand(new RegistrationId(guid), body.Bsn), ct);
+    return outcome == WithdrawOutcome.Withdrawn ? Results.NoContent() : Results.NotFound();
+});
+
+// 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) =>
 {
@@ -92,6 +116,8 @@ public sealed record SubmitRegistrationRequest(string Bsn);
 
 public sealed record DecideRequest(string Besluit);
 
+public sealed record WithdrawRequest(string Bsn);
+
 public sealed record RegistrationResponse(string RegistrationId, string Status, string? ZaakUrl);
 
 public partial class Program;

services/domain/Big.Application/BeoordeelRegistratie.cs

@@ -20,10 +20,12 @@ public sealed record BeoordeelRegistratieCommand(RegistrationId RegistrationId,
 /// <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). Both decisions are idempotent — a repeated or redelivered
+/// it, is a later sub-slice of S-12). After applying the decision it completes the Flowable
-/// decision that matches the current terminal state is a no-op, so the ACL is not called twice.
+/// <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)
+public sealed class BeoordeelRegistratie(IRegistrationStore store, IAclClient acl, IUserTaskClient tasks)
 {
     public async Task HandleAsync(BeoordeelRegistratieCommand command, CancellationToken ct = default)
     {
@@ -53,5 +55,17 @@ public sealed class BeoordeelRegistratie(IRegistrationStore store, IAclClient ac
         }
 
         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/Ports.cs

@@ -15,6 +15,14 @@ public interface IWorkflowClient
     /// aggregate. Returns the process instance id.
     /// </summary>
     Task<string> StartRegistrationProcessAsync(RegistrationId registrationId, CancellationToken ct = default);
+
+    /// <summary>
+    /// Cancel a running <c>registratie</c> process on withdrawal (S-11): correlate the
+    /// <c>RegistratieIngetrokken</c> message to the instance, tripping the interrupting message event
+    /// that ends it (ADR-0014). Best-effort — if the instance is not waiting on that message (already
+    /// ended, or not yet parked) it is a no-op; the aggregate is INGETROKKEN regardless.
+    /// </summary>
+    Task WithdrawProcessAsync(string processInstanceId, CancellationToken ct = default);
 }
 
 /// <summary>

services/domain/Big.Application/Werkbak.cs

@@ -0,0 +1,40 @@
+using Big.Domain;
+
+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, or whose registration is no longer open for beoordeling
+/// (e.g. withdrawn — S-11 — while its task lingers until the workflow cancels it), is skipped.
+/// </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 || !IsOpenForBeoordeling(registration.Status))
+                continue;
+
+            items.Add(new WerkbakItem(
+                registration.Id.ToString(), registration.Bsn, registration.Status.ToString()));
+        }
+
+        return items;
+    }
+
+    // Only registrations still open for a decision belong in the werkbak; a terminal one (decided or
+    // withdrawn — S-11) whose Beoordelen task has not yet been cleared must not surface to a behandelaar.
+    private static bool IsOpenForBeoordeling(RegistrationStatus status)
+        => status is RegistrationStatus.Ingediend or RegistrationStatus.InBehandeling;
+}

services/domain/Big.Application/WithdrawRegistration.cs

@@ -0,0 +1,55 @@
+using Big.Domain;
+
+namespace Big.Application;
+
+/// <summary>A zorgprofessional's request to withdraw their own registration ("trek aanvraag in").
+/// <paramref name="Bsn"/> is the authenticated caller (from the DigiD token, forwarded by the BFF):
+/// only the registration's own bsn may withdraw it.</summary>
+public sealed record WithdrawRegistrationCommand(RegistrationId RegistrationId, string Bsn);
+
+/// <summary>The outcome of a withdrawal request.</summary>
+public enum WithdrawOutcome
+{
+    /// <summary>The registration is now (or already was) INGETROKKEN.</summary>
+    Withdrawn,
+
+    /// <summary>No registration with that id belongs to the caller — unknown, or owned by someone
+    /// else (the two are deliberately indistinguishable, so the endpoint reveals neither).</summary>
+    NotFound,
+}
+
+/// <summary>
+/// The withdrawal use case (S-11): a zorgprofessional pulls a still-open registration back. It
+/// advances the aggregate to INGETROKKEN, persists it, then cancels the running registratie process
+/// by correlating the withdrawal message to its instance (ADR-0014), so the case leaves the
+/// behandelaar's werkbak. Idempotent — a repeated or redelivered withdrawal of an already-withdrawn
+/// registration is a no-op (not persisted or cancelled again). Cancelling is best-effort: if the
+/// registration never started a process the withdrawal still stands (the process cancel is skipped),
+/// mirroring how <see cref="BeoordeelRegistratie"/> completes its task best-effort.
+/// </summary>
+public sealed class WithdrawRegistration(IRegistrationStore store, IWorkflowClient workflow)
+{
+    public async Task<WithdrawOutcome> HandleAsync(WithdrawRegistrationCommand command, CancellationToken ct = default)
+    {
+        ArgumentNullException.ThrowIfNull(command);
+
+        var registration = await store.GetAsync(command.RegistrationId, ct);
+
+        // Unknown, or not the caller's registration: report NotFound either way (don't reveal which).
+        if (registration is null || registration.Bsn != command.Bsn)
+            return WithdrawOutcome.NotFound;
+
+        // A repeated withdrawal is a no-op: don't persist or cancel the already-withdrawn one again.
+        if (registration.Status == RegistrationStatus.Ingetrokken)
+            return WithdrawOutcome.Withdrawn;
+
+        registration.Withdraw();
+        await store.SaveAsync(registration, ct);
+
+        // Cancel the running process (if one was started) so its Beoordelen task leaves the werkbak.
+        if (registration.ProcessInstanceId is not null)
+            await workflow.WithdrawProcessAsync(registration.ProcessInstanceId, ct);
+
+        return WithdrawOutcome.Withdrawn;
+    }
+}

services/domain/Big.Domain/Registration.cs

@@ -111,7 +111,23 @@ public sealed class Registration
         Status = RegistrationStatus.Afgewezen;
     }
 
-    // A decision is only valid while the registration is still open (INGEDIEND or IN_BEHANDELING).
+    /// <summary>
+    /// Withdraw the registration — the zorgprofessional pulls their own submission back (S-11). Allowed
+    /// while it is still open (INGEDIEND or IN_BEHANDELING) and needs no zaak; a registration that has
+    /// already been decided (INGESCHREVEN/AFGEWEZEN) can no longer be withdrawn. Re-withdrawing one
+    /// already <see cref="RegistrationStatus.Ingetrokken"/> is a no-op.
+    /// </summary>
+    public void Withdraw()
+    {
+        if (Status == RegistrationStatus.Ingetrokken)
+            return;
+
+        RequireOpenForDecision(nameof(Withdraw));
+        Status = RegistrationStatus.Ingetrokken;
+    }
+
+    // A decision (or withdrawal) 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))

services/domain/Big.Domain/RegistrationStatus.cs

@@ -3,7 +3,8 @@ namespace Big.Domain;
 /// <summary>The lifecycle states a <see cref="Registration"/> moves through. Submission starts in
 /// <see cref="Ingediend"/>; a behandelaar takes it <see cref="InBehandeling"/> and decides it into one
 /// 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>
+/// A zorgprofessional can withdraw a still-open registration into <see cref="Ingetrokken"/> (S-11).
+/// The herregistratie state arrives in its own slice.</summary>
 public enum RegistrationStatus
 {
     /// <summary>Submitted by the zorgprofessional; the registratie process has been started.</summary>
@@ -17,4 +18,7 @@ public enum RegistrationStatus
 
     /// <summary>Rejected by the behandelaar. Terminal.</summary>
     Afgewezen,
+
+    /// <summary>Withdrawn by the zorgprofessional before a decision (S-11). Terminal.</summary>
+    Ingetrokken,
 }

services/domain/Big.Infrastructure/FlowableWorkflowClient.cs

@@ -23,6 +23,7 @@ public sealed class FlowableWorkflowClient(HttpClient http, FlowableOptions opti
     private const string RegistrationIdVariable = "registrationId";
     private const string ZaakUrlVariable = "zaakUrl";
     private const string BesluitVariable = "besluit";
+    private const string IngetrokkenMessage = "RegistratieIngetrokken";
 
     public async Task<string> StartRegistrationProcessAsync(RegistrationId registrationId, CancellationToken ct = default)
     {
@@ -85,6 +86,35 @@ public sealed class FlowableWorkflowClient(HttpClient http, FlowableOptions opti
         response.EnsureSuccessStatusCode();
     }
 
+    public async Task WithdrawProcessAsync(string processInstanceId, CancellationToken ct = default)
+    {
+        // Correlate the withdrawal message to the instance: find the execution subscribed to it (the
+        // interrupting message event's own execution — NOT the user task's), then deliver
+        // messageEventReceived to that execution so the process ends (ADR-0014). If nothing is
+        // subscribed (the process is not parked at Beoordelen) this is a best-effort no-op.
+        var subscribed = await GetAsync<ExecutionQueryResult>(
+            $"service/runtime/executions?messageEventSubscriptionName={IngetrokkenMessage}&processInstanceId={processInstanceId}",
+            ct);
+
+        var execution = subscribed?.Data?.FirstOrDefault();
+        if (execution is null)
+            return;
+
+        var request = new MessageEventRequest("messageEventReceived", IngetrokkenMessage);
+        using var response = await SendAsync(
+            $"service/runtime/executions/{execution.Id}", request, ct, HttpMethod.Put);
+        response.EnsureSuccessStatusCode();
+    }
+
+    private async Task<TResponse?> GetAsync<TResponse>(string path, CancellationToken ct)
+    {
+        var message = new HttpRequestMessage(HttpMethod.Get, new Uri(options.BaseUrl, path));
+        message.Headers.Authorization = new AuthenticationHeaderValue("Basic", BasicCredentials());
+        using var response = await http.SendAsync(message, ct);
+        response.EnsureSuccessStatusCode();
+        return await response.Content.ReadFromJsonAsync<TResponse>(ct);
+    }
+
     private async Task<TResponse?> PostAsync<TRequest, TResponse>(string path, TRequest body, CancellationToken ct)
     {
         using var response = await SendAsync(path, body, ct);
@@ -92,9 +122,9 @@ public sealed class FlowableWorkflowClient(HttpClient http, FlowableOptions opti
         return await response.Content.ReadFromJsonAsync<TResponse>(ct);
     }
 
-    private Task<HttpResponseMessage> SendAsync<TRequest>(string path, TRequest body, CancellationToken ct)
+    private Task<HttpResponseMessage> SendAsync<TRequest>(string path, TRequest body, CancellationToken ct, HttpMethod? method = null)
     {
-        var message = new HttpRequestMessage(HttpMethod.Post, new Uri(options.BaseUrl, path))
+        var message = new HttpRequestMessage(method ?? HttpMethod.Post, new Uri(options.BaseUrl, path))
         {
             Content = JsonContent.Create(body),
         };
@@ -132,6 +162,10 @@ public sealed class FlowableWorkflowClient(HttpClient http, FlowableOptions opti
         [property: JsonPropertyName("action")] string Action,
         [property: JsonPropertyName("variables")] IReadOnlyList<Variable> Variables);
 
+    private sealed record MessageEventRequest(
+        [property: JsonPropertyName("action")] string Action,
+        [property: JsonPropertyName("messageName")] string MessageName);
+
     private sealed record TaskQueryResult(
         [property: JsonPropertyName("data")] IReadOnlyList<UserTaskDto>? Data);
 
@@ -154,6 +188,11 @@ public sealed class FlowableWorkflowClient(HttpClient http, FlowableOptions opti
 
     private sealed record ProcessInstance([property: JsonPropertyName("id")] string Id);
 
+    private sealed record ExecutionQueryResult(
+        [property: JsonPropertyName("data")] IReadOnlyList<ExecutionDto>? Data);
+
+    private sealed record ExecutionDto([property: JsonPropertyName("id")] string Id);
+
     private sealed record AcquiredJob(
         [property: JsonPropertyName("id")] string Id,
         [property: JsonPropertyName("variables")] IReadOnlyList<Variable> Variables)

services/domain/Big.Tests/BeoordeelRegistratieTests.cs

@@ -6,8 +6,8 @@ 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 in the domain (propagating a rejection to the zaak is a later sub-slice). Both are
+/// AFGEWEZEN. Either way the decision also completes the Flowable Beoordelen task (found by
-/// idempotent so a repeated or redelivered decision is a no-op.
+/// registrationId) so the process advances. All idempotent — a repeated decision is a no-op.
 /// </summary>
 public class BeoordeelRegistratieTests
 {
@@ -18,6 +18,9 @@ public class BeoordeelRegistratieTests
         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()
     {
@@ -25,7 +28,8 @@ public class BeoordeelRegistratieTests
         var acl = new FakeAclClient();
         var registration = WithZaak();
         store.Seed(registration);
-        var handler = new BeoordeelRegistratie(store, acl);
+        var tasks = TaskFor(registration);
+        var handler = new BeoordeelRegistratie(store, acl, tasks);
 
         await handler.HandleAsync(new BeoordeelRegistratieCommand(registration.Id, BeoordelingsBesluit.Goedkeuren));
 
@@ -34,6 +38,8 @@ public class BeoordeelRegistratieTests
         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]
@@ -43,7 +49,8 @@ public class BeoordeelRegistratieTests
         var acl = new FakeAclClient();
         var registration = WithZaak();
         store.Seed(registration);
-        var handler = new BeoordeelRegistratie(store, acl);
+        var tasks = TaskFor(registration);
+        var handler = new BeoordeelRegistratie(store, acl, tasks);
 
         await handler.HandleAsync(new BeoordeelRegistratieCommand(registration.Id, BeoordelingsBesluit.Afwijzen));
 
@@ -51,6 +58,7 @@ public class BeoordeelRegistratieTests
         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]
@@ -61,7 +69,7 @@ public class BeoordeelRegistratieTests
         var registration = WithZaak();
         registration.TakeIntoBehandeling();
         store.Seed(registration);
-        var handler = new BeoordeelRegistratie(store, acl);
+        var handler = new BeoordeelRegistratie(store, acl, TaskFor(registration));
 
         await handler.HandleAsync(new BeoordeelRegistratieCommand(registration.Id, BeoordelingsBesluit.Goedkeuren));
 
@@ -73,7 +81,7 @@ public class BeoordeelRegistratieTests
     {
         var store = new FakeRegistrationStore();
         var acl = new FakeAclClient();
-        var handler = new BeoordeelRegistratie(store, acl);
+        var handler = new BeoordeelRegistratie(store, acl, new FakeUserTaskClient([]));
 
         await Assert.ThrowsAsync<ArgumentNullException>(() => handler.HandleAsync(null!));
         Assert.Equal(0, acl.ApproveCallCount);
@@ -85,7 +93,7 @@ public class BeoordeelRegistratieTests
     {
         var store = new FakeRegistrationStore();
         var acl = new FakeAclClient();
-        var handler = new BeoordeelRegistratie(store, acl);
+        var handler = new BeoordeelRegistratie(store, acl, new FakeUserTaskClient([]));
 
         var ex = await Assert.ThrowsAsync<InvalidOperationException>(() =>
             handler.HandleAsync(new BeoordeelRegistratieCommand(RegistrationId.New(), BeoordelingsBesluit.Goedkeuren)));
@@ -100,7 +108,7 @@ public class BeoordeelRegistratieTests
         var acl = new FakeAclClient();
         var registration = Registration.Submit("123456782"); // no zaak yet
         store.Seed(registration);
-        var handler = new BeoordeelRegistratie(store, acl);
+        var handler = new BeoordeelRegistratie(store, acl, TaskFor(registration));
 
         var ex = await Assert.ThrowsAsync<InvalidOperationException>(() =>
             handler.HandleAsync(new BeoordeelRegistratieCommand(registration.Id, BeoordelingsBesluit.Goedkeuren)));
@@ -115,7 +123,7 @@ public class BeoordeelRegistratieTests
         var acl = new FakeAclClient();
         var registration = WithZaak();
         store.Seed(registration);
-        var handler = new BeoordeelRegistratie(store, acl);
+        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));
@@ -131,7 +139,7 @@ public class BeoordeelRegistratieTests
         var acl = new FakeAclClient();
         var registration = WithZaak();
         store.Seed(registration);
-        var handler = new BeoordeelRegistratie(store, acl);
+        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));
@@ -139,4 +147,22 @@ public class BeoordeelRegistratieTests
         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

@@ -32,6 +32,7 @@ internal sealed class FakeWorkflowClient(string processInstanceId = "proc-1", Ac
     : IWorkflowClient
 {
     public RegistrationId? StartedFor { get; private set; }
+    public string? WithdrawnProcessInstanceId { get; private set; }
 
     public Task<string> StartRegistrationProcessAsync(RegistrationId registrationId, CancellationToken ct = default)
     {
@@ -39,6 +40,35 @@ internal sealed class FakeWorkflowClient(string processInstanceId = "proc-1", Ac
         StartedFor = registrationId;
         return Task.FromResult(processInstanceId);
     }
+
+    public Task WithdrawProcessAsync(string processInstanceId, CancellationToken ct = default)
+    {
+        WithdrawnProcessInstanceId = processInstanceId;
+        return Task.CompletedTask;
+    }
+}
+
+/// <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

services/domain/Big.Tests/FlowableWorkflowClientTests.cs

@@ -242,6 +242,61 @@ public class FlowableWorkflowClientTests
         Assert.Contains($"\"value\":\"{expected}\"", capture.Body);
     }
 
+    [Fact]
+    public async Task Withdraw_process_correlates_the_message_to_the_subscribed_execution()
+    {
+        HttpRequestMessage? getReq = null;
+        HttpRequestMessage? putReq = null;
+        string? putBody = null;
+        var client = Client(new StubHandler(async req =>
+        {
+            if (req.Method == HttpMethod.Get)
+            {
+                getReq = req;
+                return new HttpResponseMessage(HttpStatusCode.OK)
+                {
+                    Content = new StringContent("""{"data":[{"id":"exec-9"}]}""", Encoding.UTF8, "application/json"),
+                };
+            }
+            putReq = req;
+            putBody = await req.Content!.ReadAsStringAsync();
+            return new HttpResponseMessage(HttpStatusCode.OK);
+        }));
+
+        await client.WithdrawProcessAsync("pi-1");
+
+        // 1. Find the execution subscribed to the withdrawal message for this instance.
+        Assert.Equal(HttpMethod.Get, getReq!.Method);
+        Assert.Contains("service/runtime/executions", getReq.RequestUri!.ToString());
+        Assert.Contains("messageEventSubscriptionName=RegistratieIngetrokken", getReq.RequestUri!.Query);
+        Assert.Contains("processInstanceId=pi-1", getReq.RequestUri!.Query);
+        // 2. Deliver messageEventReceived to that execution (PUT), tripping the interrupting event.
+        Assert.Equal(HttpMethod.Put, putReq!.Method);
+        Assert.Equal("http://flowable/flowable-rest/service/runtime/executions/exec-9",
+            putReq.RequestUri!.ToString());
+        Assert.Contains("\"action\":\"messageEventReceived\"", putBody);
+        Assert.Contains("\"messageName\":\"RegistratieIngetrokken\"", putBody);
+    }
+
+    [Fact]
+    public async Task Withdraw_process_is_a_no_op_when_no_execution_is_subscribed()
+    {
+        var methods = new List<HttpMethod>();
+        var client = Client(new StubHandler(req =>
+        {
+            methods.Add(req.Method);
+            return Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK)
+            {
+                Content = new StringContent("""{"data":[]}""", Encoding.UTF8, "application/json"),
+            });
+        }));
+
+        await client.WithdrawProcessAsync("pi-1");
+
+        // No subscribed execution → no message delivered (best-effort), no throw.
+        Assert.DoesNotContain(HttpMethod.Put, methods);
+    }
+
     [Fact]
     public async Task Complete_beoordeling_throws_when_flowable_rejects_the_request()
     {

services/domain/Big.Tests/RegistrationTests.cs

@@ -217,4 +217,72 @@ public class RegistrationTests
         Assert.Contains("Afgewezen", rejectEx.Message);
         Assert.Equal(RegistrationStatus.Afgewezen, registration.Status);
     }
+
+    [Fact]
+    public void Withdrawing_an_ingediend_registration_sets_it_ingetrokken()
+    {
+        var registration = Registration.Submit("123456782");
+
+        registration.Withdraw();
+
+        Assert.Equal(RegistrationStatus.Ingetrokken, registration.Status);
+    }
+
+    [Fact]
+    public void Withdrawing_an_in_behandeling_registration_sets_it_ingetrokken()
+    {
+        // A citizen can still pull a registration back while a behandelaar has it in behandeling.
+        var registration = Registration.Submit("123456782");
+        registration.TakeIntoBehandeling();
+
+        registration.Withdraw();
+
+        Assert.Equal(RegistrationStatus.Ingetrokken, registration.Status);
+    }
+
+    [Fact]
+    public void Withdrawing_needs_no_zaak()
+    {
+        // Withdrawal is the citizen's own action and does not depend on the zaak having been opened.
+        var registration = Registration.Submit("123456782");
+
+        registration.Withdraw();
+
+        Assert.Equal(RegistrationStatus.Ingetrokken, registration.Status);
+        Assert.Null(registration.ZaakUrl);
+    }
+
+    [Fact]
+    public void Re_withdrawing_an_already_ingetrokken_registration_is_idempotent()
+    {
+        var registration = Registration.Submit("123456782");
+        registration.Withdraw();
+
+        registration.Withdraw();
+
+        Assert.Equal(RegistrationStatus.Ingetrokken, registration.Status);
+    }
+
+    [Fact]
+    public void Withdrawing_an_approved_registration_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.Withdraw());
+        Assert.Contains("only an INGEDIEND", ex.Message);
+        Assert.Equal(RegistrationStatus.Ingeschreven, registration.Status);
+    }
+
+    [Fact]
+    public void Withdrawing_a_rejected_registration_is_rejected()
+    {
+        var registration = Registration.Submit("123456782");
+        registration.Reject();
+
+        var ex = Assert.Throws<InvalidOperationException>(() => registration.Withdraw());
+        Assert.Contains("only an INGEDIEND", ex.Message);
+        Assert.Equal(RegistrationStatus.Afgewezen, registration.Status);
+    }
 }

services/domain/Big.Tests/WerkbakTests.cs

@@ -0,0 +1,64 @@
+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());
+    }
+
+    [Fact]
+    public async Task Skips_a_task_whose_registration_is_no_longer_open()
+    {
+        // A withdrawn registration (S-11) may still have a Beoordelen task lingering until the workflow
+        // cancels it; the werkbak lists only registrations still open for beoordeling, so it drops off.
+        var store = new FakeRegistrationStore();
+        var registration = Registration.Submit("123456782");
+        registration.Withdraw();
+        store.Seed(registration);
+        var tasks = new FakeUserTaskClient([new BeoordelingTask("task-1", registration.Id)]);
+        var werkbak = new Werkbak(tasks, store);
+
+        Assert.Empty(await werkbak.GetAsync());
+    }
+}

services/domain/Big.Tests/WithdrawRegistrationTests.cs

@@ -0,0 +1,123 @@
+using Big.Application;
+using Big.Domain;
+
+namespace Big.Tests;
+
+public class WithdrawRegistrationTests
+{
+    private const string Bsn = "123456782";
+
+    private static Registration Submitted(string processInstanceId = "proc-1")
+    {
+        var registration = Registration.Submit(Bsn);
+        registration.RecordProcessStarted(processInstanceId);
+        return registration;
+    }
+
+    private static WithdrawRegistrationCommand Command(RegistrationId id, string bsn = Bsn) => new(id, bsn);
+
+    [Fact]
+    public async Task Withdrawing_marks_the_registration_ingetrokken_and_persists_it()
+    {
+        var store = new FakeRegistrationStore();
+        var registration = Submitted();
+        store.Seed(registration);
+        var handler = new WithdrawRegistration(store, new FakeWorkflowClient());
+
+        var outcome = await handler.HandleAsync(Command(registration.Id));
+
+        Assert.Equal(WithdrawOutcome.Withdrawn, outcome);
+        var saved = await store.GetAsync(registration.Id);
+        Assert.Equal(RegistrationStatus.Ingetrokken, saved!.Status);
+        Assert.Equal(1, store.SaveCount);
+    }
+
+    [Fact]
+    public async Task Withdrawing_cancels_the_running_process()
+    {
+        var store = new FakeRegistrationStore();
+        var registration = Submitted("proc-42");
+        store.Seed(registration);
+        var workflow = new FakeWorkflowClient();
+        var handler = new WithdrawRegistration(store, workflow);
+
+        await handler.HandleAsync(Command(registration.Id));
+
+        // The process the registration recorded at submit is cancelled (ADR-0014).
+        Assert.Equal("proc-42", workflow.WithdrawnProcessInstanceId);
+    }
+
+    [Fact]
+    public async Task Withdrawing_before_a_process_was_started_still_marks_ingetrokken()
+    {
+        var store = new FakeRegistrationStore();
+        var registration = Registration.Submit(Bsn); // no RecordProcessStarted
+        store.Seed(registration);
+        var workflow = new FakeWorkflowClient();
+        var handler = new WithdrawRegistration(store, workflow);
+
+        await handler.HandleAsync(Command(registration.Id));
+
+        Assert.Equal(RegistrationStatus.Ingetrokken, (await store.GetAsync(registration.Id))!.Status);
+        Assert.Null(workflow.WithdrawnProcessInstanceId);
+    }
+
+    [Fact]
+    public async Task A_different_bsn_cannot_withdraw_the_registration()
+    {
+        // Owner-scoping: only the zorgprofessional who submitted may withdraw. Another bsn is told
+        // NotFound (we don't reveal the registration exists) and nothing is changed.
+        var store = new FakeRegistrationStore();
+        var registration = Submitted();
+        store.Seed(registration);
+        var workflow = new FakeWorkflowClient();
+        var handler = new WithdrawRegistration(store, workflow);
+
+        var outcome = await handler.HandleAsync(Command(registration.Id, bsn: "999999990"));
+
+        Assert.Equal(WithdrawOutcome.NotFound, outcome);
+        Assert.Equal(RegistrationStatus.Ingediend, (await store.GetAsync(registration.Id))!.Status);
+        Assert.Equal(0, store.SaveCount);
+        Assert.Null(workflow.WithdrawnProcessInstanceId);
+    }
+
+    [Fact]
+    public async Task Rejects_a_null_command_without_touching_the_store()
+    {
+        var store = new FakeRegistrationStore();
+        var handler = new WithdrawRegistration(store, new FakeWorkflowClient());
+
+        await Assert.ThrowsAsync<ArgumentNullException>(() => handler.HandleAsync(null!));
+        Assert.Equal(0, store.SaveCount);
+    }
+
+    [Fact]
+    public async Task Withdrawing_an_unknown_registration_is_not_found()
+    {
+        var store = new FakeRegistrationStore();
+        var handler = new WithdrawRegistration(store, new FakeWorkflowClient());
+
+        var outcome = await handler.HandleAsync(Command(RegistrationId.New()));
+
+        Assert.Equal(WithdrawOutcome.NotFound, outcome);
+        Assert.Equal(0, store.SaveCount);
+    }
+
+    [Fact]
+    public async Task Re_withdrawing_an_already_ingetrokken_registration_is_idempotent()
+    {
+        var store = new FakeRegistrationStore();
+        var registration = Submitted();
+        store.Seed(registration);
+        var workflow = new FakeWorkflowClient();
+        var handler = new WithdrawRegistration(store, workflow);
+
+        await handler.HandleAsync(Command(registration.Id));
+        var second = await handler.HandleAsync(Command(registration.Id));
+
+        // The second withdrawal is a no-op: still Withdrawn, but the aggregate is not persisted again.
+        Assert.Equal(WithdrawOutcome.Withdrawn, second);
+        Assert.Equal(1, store.SaveCount);
+        Assert.Equal(RegistrationStatus.Ingetrokken, (await store.GetAsync(registration.Id))!.Status);
+    }
+}

tests/acceptance/Features/EenRegistratieBeoordelen.feature

@@ -15,6 +15,7 @@ Feature: Een registratie beoordelen
     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
@@ -22,3 +23,4 @@ Feature: Een registratie beoordelen
     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/EenRegistratieBeoordelenSteps.cs

@@ -16,6 +16,7 @@ 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")]
@@ -25,6 +26,8 @@ public sealed class EenRegistratieBeoordelenSteps
         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")]
@@ -37,7 +40,7 @@ public sealed class EenRegistratieBeoordelenSteps
 
     [When("the behandelaar decides \"(.*)\"")]
     public async Task WhenTheBehandelaarDecides(string besluit)
-        => await new BeoordeelRegistratie(_store, _acl).HandleAsync(
+        => await new BeoordeelRegistratie(_store, _acl, _tasks).HandleAsync(
             new BeoordeelRegistratieCommand(_id, Enum.Parse<BeoordelingsBesluit>(besluit, ignoreCase: true)));
 
     [Then("the registration has status \"(.*)\"")]
@@ -55,4 +58,8 @@ public sealed class EenRegistratieBeoordelenSteps
     [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/Support/BffAcceptanceHost.cs

@@ -68,6 +68,15 @@ public sealed class CapturingDomainClient : IDomainClient
         SubmittedBsn = bsn;
         return Task.FromResult(new SubmitAccepted("reg-acc-1", "Ingediend"));
     }
+
+    public Task<bool> WithdrawRegistrationAsync(string registrationId, string bsn, CancellationToken ct = default)
+        => Task.FromResult(true);
+
+    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

@@ -11,12 +11,19 @@ public sealed class InMemoryWorkflowClient : IWorkflowClient
     public const string StartedProcessInstanceId = "proc-acc-1";
 
     public RegistrationId? StartedFor { get; private set; }
+    public string? WithdrawnProcessInstanceId { get; private set; }
 
     public Task<string> StartRegistrationProcessAsync(RegistrationId registrationId, CancellationToken ct = default)
     {
         StartedFor = registrationId;
         return Task.FromResult(StartedProcessInstanceId);
     }
+
+    public Task WithdrawProcessAsync(string processInstanceId, CancellationToken ct = default)
+    {
+        WithdrawnProcessInstanceId = processInstanceId;
+        return Task.CompletedTask;
+    }
 }
 
 /// <summary>An in-memory ACL stand-in: records the bsn it opened a zaak for and returns a fixed URL,
@@ -43,6 +50,29 @@ 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/e2e/playwright.config.ts

@@ -3,6 +3,9 @@ import { defineConfig, devices } from '@playwright/test';
 // The e2e runs inside the compose network (infra/run-e2e-check.sh); baseURL defaults to the
 // self-service service. Keep timeouts generous — the first navigation triggers the DigiD flow.
 const baseURL = process.env.SELF_SERVICE_URL ?? 'http://self-service';
+// The behandel portal is a second origin the happy path visits (staff approve from the werkbak);
+// it needs the same insecure-origin-as-secure treatment as self-service for the PKCE login (below).
+const behandelURL = process.env.BEHANDEL_URL ?? 'http://behandel';
 
 export default defineConfig({
   testDir: '.',
@@ -22,7 +25,9 @@ export default defineConfig({
     // the production HTTPS context. This flag is only honoured by the full Chromium build (new
     // headless), not Playwright's default headless-shell, so pin `channel: 'chromium'`.
     channel: 'chromium',
-    launchOptions: { args: [`--unsafely-treat-insecure-origin-as-secure=${baseURL}`] },
+    launchOptions: {
+      args: [`--unsafely-treat-insecure-origin-as-secure=${baseURL},${behandelURL}`],
+    },
   },
   projects: [{ name: 'chromium', use: { ...devices['Desktop Chrome'] } }],
 });

tests/e2e/registration.spec.ts

@@ -1,10 +1,11 @@
 import { expect, test } from '@playwright/test';
 
-// Walking-skeleton happy path (S-08d + S-09 + S-09b): a zorgprofessional logs in via mock DigiD and
+// Walking-skeleton happy path (S-08d + S-09 + S-09b + S-12): a zorgprofessional logs in via mock
-// submits through the self-service portal → BFF → domain; the entry appears in the openbaar register
+// DigiD and submits through the self-service portal → BFF → domain; the entry appears in the openbaar
-// as INGEDIEND; a behandelaar approves it via the temporary admin endpoint; the approval flows via the
+// register as INGEDIEND; a behandelaar then logs in to the behandel portal, finds the registration in
-// ACL → NRC → event-subscriber → projection, and the openbaar register then shows it as INGESCHREVEN.
+// the werkbak, and approves it (goedkeuren); the decision completes the Flowable Beoordelen task and
-test('DigiD login → submit → public INGEDIEND → approve → public INGESCHREVEN', async ({ page, request }) => {
+// flows via the ACL → NRC → event-subscriber → projection, and the openbaar register shows INGESCHREVEN.
+test('DigiD submit → public INGEDIEND → behandelaar goedkeurt → public INGESCHREVEN', async ({ page }) => {
   // Visiting the guarded page redirects to the Keycloak (mock DigiD) login.
   await page.goto('/');
 
@@ -43,21 +44,42 @@ test('DigiD login → submit → public INGEDIEND → approve → public INGESCH
   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
+  // A behandelaar picks the registration up in the behandel-portal werkbak and approves it
-  // behandelaar would until the behandel-portal exists — S-12). The zaak is opened off the request
+  // (goedkeuren) — the S-12 flow that replaces the temporary admin endpoint. Navigating here switches
-  // path by the worker, so wait for it before approving.
+  // to the medewerker realm (a different Keycloak realm than the citizen's digid session).
+  await page.goto('http://behandel/');
+  await page.locator('#username').fill('merel-behandelaar');
+  await page.locator('#password').fill('test123');
+  await page.locator('#kc-login').click();
+
+  await expect(page.getByRole('heading', { name: /Werkbak/i })).toBeVisible();
+
+  // The registration parks at the Beoordelen user task only after the worker has opened its zaak, so
+  // it appears in the werkbak asynchronously — reload until this reference's row shows up. Target the
+  // decide button by reference (not a generic "Goedkeuren"): the shared verify stack holds other open
+  // tasks, so a positional match could act on someone else's registration.
+  const goedkeuren = page.getByRole('button', { name: `Goedkeuren ${reference}` });
   await expect
     .poll(async () => {
-      const res = await request.get(`http://domain:8080/registrations/${reference}`);
+      await page.reload();
-      return res.ok() ? (await res.json()).zaakUrl : null;
+      return goedkeuren.count();
     }, { timeout: 30_000, intervals: [1_000, 2_000, 3_000, 5_000] })
-    .toBeTruthy();
+    .toBeGreaterThan(0);
 
-  const approve = await request.post(`http://domain:8080/registrations/${reference}/approve`);
+  // Click and wait for the decide POST to finish (204) BEFORE leaving the page. `click()` only
-  expect(approve.status()).toBe(204);
+  // dispatches the request; navigating away immediately cancels it in flight (nginx logs a 499) and
+  // the decision never reaches the domain — so the registration would stay INGEDIEND.
+  const decided = page.waitForResponse(
+    (r) =>
+      r.url().includes(`/behandel/registrations/${reference}/decide`) &&
+      r.request().method() === 'POST',
+  );
+  await goedkeuren.click();
+  expect((await decided).status()).toBe(204);
 
-  // The approval flows back to the projection; the openbaar register now shows *our* row (matched by
+  // The approval flows back to the projection; back on the openbaar register *our* row (matched by
-  // its reference) as INGESCHREVEN.
+  // its reference) now shows INGESCHREVEN.
+  await page.goto('http://openbaar/');
   await expect
     .poll(async () => {
       await page.reload();

workflows/registratie.bpmn

@@ -11,7 +11,13 @@
        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. -->
+       variable so the werkbak can correlate each task back to its aggregate.
+       S-11 adds withdrawal: while parked at Beoordelen the citizen can trek de aanvraag in — an
+       interrupting message boundary event (RegistratieIngetrokken) cancels the task and ends the
+       process via a dedicated "ingetrokken" end (ADR-0014). The Workflow Client delivers the message
+       to the task's execution; the BPMN owns the cancellation path. -->
+  <message id="Message_Ingetrokken" name="RegistratieIngetrokken"/>
+
   <process id="registratie" name="Registratie ontvangen" isExecutable="true">
 
     <startEvent id="start" name="Registratie ontvangen"/>
@@ -29,6 +35,16 @@
     <sequenceFlow id="flow3" sourceRef="Beoordelen" targetRef="end"/>
 
     <endEvent id="end" name="Registratie beoordeeld"/>
+
+    <!-- Withdrawal (S-11): interrupting message boundary event on Beoordelen. On RegistratieIngetrokken
+         the task is cancelled and the process ends as "ingetrokken". -->
+    <boundaryEvent id="Ingetrokken" attachedToRef="Beoordelen" cancelActivity="true">
+      <messageEventDefinition messageRef="Message_Ingetrokken"/>
+    </boundaryEvent>
+
+    <sequenceFlow id="flow4" sourceRef="Ingetrokken" targetRef="endIngetrokken"/>
+
+    <endEvent id="endIngetrokken" name="Registratie ingetrokken"/>
   </process>
 
   <bpmndi:BPMNDiagram id="diagram">
@@ -57,6 +73,16 @@
         <omgdi:waypoint x="510" y="115"/>
         <omgdi:waypoint x="580" y="115"/>
       </bpmndi:BPMNEdge>
+      <bpmndi:BPMNShape id="s_ingetrokken" bpmnElement="Ingetrokken">
+        <omgdc:Bounds x="435" y="135" width="30" height="30"/>
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape id="s_endIngetrokken" bpmnElement="endIngetrokken">
+        <omgdc:Bounds x="435" y="220" width="30" height="30"/>
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="e_flow4" bpmnElement="flow4">
+        <omgdi:waypoint x="450" y="165"/>
+        <omgdi:waypoint x="450" y="220"/>
+      </bpmndi:BPMNEdge>
     </bpmndi:BPMNPlane>
   </bpmndi:BPMNDiagram>
 </definitions>