diff --git a/src/app/shared/infrastructure/role.interceptor.spec.ts b/src/app/shared/infrastructure/role.interceptor.spec.ts
new file mode 100644
index 0000000..38cf215
--- /dev/null
+++ b/src/app/shared/infrastructure/role.interceptor.spec.ts
@@ -0,0 +1,49 @@
+import { describe, it, expect, vi } from 'vitest';
+import { roleInterceptor } from './role.interceptor';
+
+// currentRole() reads window.location; pin it so the test is about routing, not the shim.
+vi.mock('./role', () => ({ currentRole: () => 'admin' }));
+
+// Minimal stand-in for HttpRequest — the interceptor only reads `url` and calls
+// `clone({ setHeaders })`. Avoids importing @angular/common/http at runtime (its XHR
+// chunk needs the JIT compiler under vitest).
+function fakeReq(url: string) {
+  const make = (headers: Map<string, string>) => ({
+    url,
+    headers,
+    clone(opts: { setHeaders: Record<string, string> }) {
+      const next = new Map(headers);
+      for (const [k, v] of Object.entries(opts.setHeaders)) next.set(k, v);
+      return make(next);
+    },
+  });
+  return make(new Map());
+}
+
+/** Run the interceptor and return the request it forwarded to `next`. */
+function forward(url: string) {
+  let seen!: ReturnType<typeof fakeReq>;
+  const next = (r: ReturnType<typeof fakeReq>) => {
+    seen = r;
+    return undefined;
+  };
+  // Cast: the fake matches the shape the interceptor actually touches.
+  (roleInterceptor as unknown as (req: unknown, next: unknown) => unknown)(fakeReq(url), next);
+  return seen;
+}
+
+describe('roleInterceptor', () => {
+  it.each([
+    '/api/v1/brief',
+    '/api/v1/admin/org-template',
+    '/api/v1/stamdata', // WP-29: the admin stamdata reads 403 without X-Role
+    '/api/v1/stamdata/professions?peildatum=1999-01-01',
+    '/api/v1/me',
+  ])('stamps X-Role on the role-aware endpoint %s', (url) => {
+    expect(forward(url).headers.get('X-Role')).toBe('admin');
+  });
+
+  it('leaves an unrelated endpoint untouched', () => {
+    expect(forward('/api/v1/duo/diplomas').headers.has('X-Role')).toBe(false);
+  });
+});
diff --git a/src/app/shared/infrastructure/role.interceptor.ts b/src/app/shared/infrastructure/role.interceptor.ts
index 123ed4a..e518348 100644
--- a/src/app/shared/infrastructure/role.interceptor.ts
+++ b/src/app/shared/infrastructure/role.interceptor.ts
@@ -4,11 +4,17 @@ import { currentRole } from './role';
 /**
  * Dev-only: stamps role-aware requests with the current `?role=` as an `X-Role`
  * header so the backend can enforce the drafter/approver/admin rules. Only the
- * brief, org-template and /me endpoints carry it (WP-23 widened the set — /me must
- * see the role or `AccessStore` could never learn a capability); everything else
- * is untouched.
+ * brief, org-template, stamdata and /me endpoints carry it (WP-23 widened the set —
+ * /me must see the role or `AccessStore` could never learn a capability; WP-29 added
+ * /stamdata, whose admin-only reads 403 without it); everything else is untouched.
+ * A new admin-gated endpoint MUST be added here or its page silently 403s.
  */
-const ROLE_AWARE = ['/api/v1/brief', '/api/v1/admin/org-template', '/api/v1/me'];
+const ROLE_AWARE = [
+  '/api/v1/brief',
+  '/api/v1/admin/org-template',
+  '/api/v1/stamdata',
+  '/api/v1/me',
+];
 
 export const roleInterceptor: HttpInterceptorFn = (req, next) => {
   if (!ROLE_AWARE.some((prefix) => req.url.includes(prefix))) return next(req);