diff --git a/docker/frontend/scripts/scan-nav-check.mjs b/docker/frontend/scripts/scan-nav-check.mjs
index 6b1f736..1ce9c45 100644
--- a/docker/frontend/scripts/scan-nav-check.mjs
+++ b/docker/frontend/scripts/scan-nav-check.mjs
@@ -209,6 +209,13 @@ await page.click('[data-key="lib-studio"]');
 await page.waitForSelector('[data-key="nav-library"]', { timeout: 15_000 });
 step('the handover stays in the page, it does not reload it', await noReload(), `${await docs()} document load(s)`);
 step('and it lands in the studio', new URL(page.url()).pathname === '/app', page.url());
+// The reading belongs to the tab, so the header of the screen that did not start
+// it says it is still going, beside the way back into the catalogue.
+const badge = await page
+  .waitForSelector('[data-key="studio-scan-count"]', { timeout: 15_000 })
+  .then((el) => el.textContent())
+  .catch(() => null);
+step('the studio header shows the reading the tab is doing', /^\d+\/\d+$/.test(badge ?? ''), String(badge));
 
 // Back to the catalogue mid-scan: the screen that started the scan is gone and
 // back, and the roll is still being read — the reading belongs to the tab.
diff --git a/docker/frontend/src/styles/app.css b/docker/frontend/src/styles/app.css
index e5180ae..9fe92de 100644
--- a/docker/frontend/src/styles/app.css
+++ b/docker/frontend/src/styles/app.css
@@ -1061,6 +1061,9 @@ input[type="range"] { width: 100%; accent-color: var(--accent); }
   animation: lib-spin 0.7s linear infinite;
 }
 @keyframes lib-spin { to { transform: rotate(360deg); } }
+/* The same ring, out in the header: the reading belongs to this tab, not to a
+   screen, so the studio says so too while it runs. */
+.lib-scan { display: inline-flex; align-items: center; gap: 6px; white-space: nowrap; }
 @media (prefers-reduced-motion: reduce) {
   .lib-spin { animation-duration: 2.4s; }
 }
diff --git a/docker/frontend/src/ui/TopBar.tsx b/docker/frontend/src/ui/TopBar.tsx
index 78b4b16..d63a675 100644
--- a/docker/frontend/src/ui/TopBar.tsx
+++ b/docker/frontend/src/ui/TopBar.tsx
@@ -1,6 +1,7 @@
-import { useEffect, useRef, useState } from 'react';
+import { useEffect, useReducer, useRef, useState } from 'react';
 import { useI18n, LANGS } from '../i18n/I18nProvider';
 import { ACCENTS, FONT_SETS, useTheme, type FontSetId } from '../theme/ThemeProvider';
+import { scanSession, watchScan } from '../engine/library';
 import { Avatar } from './Avatar';
 import type { User } from '../api';
 
@@ -53,6 +54,16 @@ export function TopBar({
   const [menu, setMenu] = useState<'theme' | 'lang' | 'account' | null>(null);
   const wrap = useRef<HTMLDivElement>(null);
 
+  // The catalogue's own reading runs in this tab whatever screen is up, so the
+  // header says so while it does.
+  const live = scanSession();
+  const [, bump] = useReducer((n: number) => n + 1, 0);
+  useEffect(() => {
+    const unwatch = watchScan(() => bump());
+    bump(); // a scan already running when the studio comes up
+    return unwatch;
+  }, []);
+
   useEffect(() => {
     if (!menu) return;
     const away = (e: MouseEvent) => {
@@ -100,6 +111,20 @@ export function TopBar({
 
       {/* The catalogue is a page of its own, open to guests as much as to
           members — it reads the visitor's own folders and never the server. */}
+      {live ? (
+        <span
+          className="hint lib-scan"
+          data-key="studio-scan"
+          title={t('lib.scanning', {
+            done: live.progress.done,
+            total: live.progress.total,
+            added: live.progress.added,
+          })}
+        >
+          <span className="lib-spin" aria-hidden="true" />
+          <span data-key="studio-scan-count">{`${live.progress.done}/${live.progress.total}`}</span>
+        </span>
+      ) : null}
       <a className="btn ghost" data-key="nav-library" href="/library">{t('nav.library')}</a>
       <button type="button" className="btn ghost" onClick={onReset}>{t('act.reset')}</button>
       <button