diff --git a/CHANGELOG.md b/CHANGELOG.md
index bf54e1d61..f1dc9cbb9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -35,6 +35,8 @@
 
 ### Fixed
 
+- **Mobile titlebar now prioritizes the session title, with tap-to-reveal and long-press actions.** On mobile the titlebar gives the session title priority (ellipsized when long) over surrounding chrome; tapping the title reveals the full title in a popover, and a long-press opens the session actions. Listener-leak-safe (tap wired once per element, outside-click handler cleaned up on dismiss/switch; long-press guarded against double-fire, cancelled on touchmove). Read-only sessions are skipped, and desktop is untouched (touch-gated). Thanks @rodboev. (#4574, #4520)
+
 - **Mobile approval dialog and touch targets are easier to tap.** At mobile width the approval card's action buttons now lay out as a clean 2-column grid (Allow once / Allow session / Always allow / Deny) with the "Skip all this session" YOLO button full-width below, every button at a 44px minimum touch target; the titlebar new-chat/reload and the mobile sidebar-close controls are also bumped to 44px. Mobile-scoped (inside the mobile media query) — desktop layout is unchanged. Thanks @disco32r. (#5019)
 
 - **`/pet` now works in the WebUI, handing off to the Desktop Companion extension.** Typing `/pet` (and its subcommands) is intercepted client-side and routed to the petdex companion extension with graceful per-stage guidance when the extension isn't installed; the command output is XSS-safe. Thanks @rodboev. (#5168, #4843)
diff --git a/static/panels.js b/static/panels.js
index 976c3287a..2bb7e2635 100644
--- a/static/panels.js
+++ b/static/panels.js
@@ -59,7 +59,7 @@ function syncAppTitlebar() {
   if (panel === 'chat' && typeof S !== 'undefined' && S && S.session) {
     mainText = S.session.title || (typeof t === 'function' ? t('untitled') : 'Untitled');
     const vis = Array.isArray(S.messages) ? S.messages.filter(m => m && m.role && m.role !== 'tool') : [];
-    if (typeof t === 'function') subText = t('n_messages', vis.length);
+    subText = String(vis.length);
     sourceLabel = S.session.source_label || S.session.source_tag || S.session.raw_source || '';
     // Recovered sidecars stamp source_label 'WebUI' (api/session_recovery.py); don't badge a native session as its own source (#3338).
     if (/^webui$/i.test(sourceLabel)) sourceLabel = '';
@@ -153,6 +153,102 @@ function syncAppTitlebar() {
       inp.select();
     };
   }
+
+  // Dismiss stale popover on session/panel switch
+  const _existingPop = document.querySelector('.app-titlebar-title-popover');
+  if (_existingPop) {
+    _existingPop.remove(); titleEl._titlePopover = null;
+    if (titleEl._popoverOutsideHandler) {
+      document.removeEventListener('click', titleEl._popoverOutsideHandler, true);
+      titleEl._popoverOutsideHandler = null;
+    }
+  }
+
+  // Mobile touch interactions
+  if ('ontouchstart' in window) {
+    // Tap-to-reveal full title popover — wired once per element lifetime
+    if (!titleEl._mobileTouchWired) {
+      titleEl._mobileTouchWired = true;
+      titleEl._titlePopover = null;
+      const _dismissTitlePopover = () => {
+        if (titleEl._titlePopover) { titleEl._titlePopover.remove(); titleEl._titlePopover = null; }
+        if (titleEl._popoverOutsideHandler) {
+          document.removeEventListener('click', titleEl._popoverOutsideHandler, true);
+          titleEl._popoverOutsideHandler = null;
+        }
+      };
+      titleEl.addEventListener('click', function _onTitleClick(e) {
+        if (_renamingAppTitlebar) return;
+        if (titleEl._titlePopover) {
+          _dismissTitlePopover();
+          return;
+        }
+        e.stopPropagation();
+        const pop = document.createElement('div');
+        pop.className = 'app-titlebar-title-popover';
+        pop.textContent = (S && S.session && S.session.title) ||
+          (typeof t === 'function' ? t('untitled') : 'Untitled');
+        document.body.appendChild(pop);
+        const rect = titleEl.getBoundingClientRect();
+        pop.style.top = (rect.bottom + 6) + 'px';
+        pop.style.left = Math.max(8, rect.left) + 'px';
+        pop.style.maxWidth = (window.innerWidth - 16) + 'px';
+        titleEl._titlePopover = pop;
+        const _outside = titleEl._popoverOutsideHandler = (ev) => {
+          if (!pop.contains(ev.target) && ev.target !== titleEl) {
+            _dismissTitlePopover();
+            document.removeEventListener('click', _outside, true);
+            titleEl._popoverOutsideHandler = null;
+          }
+        };
+        setTimeout(() => document.addEventListener('click', _outside, true), 0);
+      }, { passive: true });
+    }
+
+    // Long-press → session action menu (re-evaluated each sync so late-arriving sessions attach)
+    if (!titleEl._mobileLpWired && panel === 'chat' && S && S.session &&
+        !S.session.read_only && !S.session.is_read_only &&
+        typeof _openSessionActionMenu === 'function') {
+      titleEl._mobileLpWired = true;
+      let _lpTimer = null;
+      let _lpHandled = false;
+      let _lpStartX = 0, _lpStartY = 0;
+      const _lpDelay = typeof SESSION_LONG_PRESS_DELAY_MS !== 'undefined' ?
+        SESSION_LONG_PRESS_DELAY_MS : 400;
+      titleEl.addEventListener('touchstart', (e) => {
+        const touch = e.changedTouches && e.changedTouches[0];
+        if (!touch) return;
+        if (_lpTimer) { clearTimeout(_lpTimer); _lpTimer = null; }
+        _lpHandled = false; _lpStartX = touch.clientX; _lpStartY = touch.clientY;
+        titleEl.classList.add('long-pressing');
+        _lpTimer = setTimeout(() => {
+          _lpTimer = null;
+          if (_lpHandled) return;
+          _lpHandled = true;
+          titleEl.classList.remove('long-pressing');
+          _openSessionActionMenu(S.session, titleEl);
+        }, _lpDelay);
+      }, { passive: true });
+      titleEl.addEventListener('touchmove', (e) => {
+        if (!_lpTimer) return;
+        const touch = e.changedTouches && e.changedTouches[0];
+        if (!touch) return;
+        if (Math.abs(touch.clientX - _lpStartX) > 10 || Math.abs(touch.clientY - _lpStartY) > 10) {
+          clearTimeout(_lpTimer); _lpTimer = null;
+          titleEl.classList.remove('long-pressing');
+        }
+      }, { passive: true });
+      titleEl.addEventListener('touchend', (e) => {
+        clearTimeout(_lpTimer); _lpTimer = null;
+        titleEl.classList.remove('long-pressing');
+        if (_lpHandled) { e.preventDefault(); e.stopPropagation(); }
+      }, { passive: false });
+      titleEl.addEventListener('touchcancel', () => {
+        clearTimeout(_lpTimer); _lpTimer = null; _lpHandled = false;
+        titleEl.classList.remove('long-pressing');
+      }, { passive: true });
+    }
+  }
 }
 
 function _beginSettingsPanelSession() {
diff --git a/static/style.css b/static/style.css
index f3b12d6c4..cd976b278 100644
--- a/static/style.css
+++ b/static/style.css
@@ -1386,6 +1386,7 @@
   .app-titlebar-title{font-size:12px;font-weight:600;color:var(--text);letter-spacing:-.01em;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-width:60vw;}
   .app-titlebar-sub{font-size:10px;color:var(--muted);background:var(--hover-bg);padding:2px 7px;border-radius:4px;font-family:'SF Mono',ui-monospace,monospace;white-space:nowrap;flex-shrink:0;}
   .app-titlebar-sub[hidden]{display:none;}
+  .app-titlebar-title-popover{position:fixed;z-index:300;background:var(--surface);border:1px solid var(--border);border-radius:8px;padding:8px 12px;font-size:13px;color:var(--text);box-shadow:0 4px 16px rgba(0,0,0,.18);word-break:break-word;line-height:1.4;max-width:calc(100vw - 16px);pointer-events:auto;}
   .app-titlebar-hamburger,.app-titlebar-spacer{display:none;width:44px;height:44px;flex-shrink:0;}
   .app-titlebar-hamburger{-webkit-app-region:no-drag;align-items:center;justify-content:center;background:none;border:none;color:var(--muted);border-radius:8px;cursor:pointer;padding:0;-webkit-tap-highlight-color:transparent;transition:background-color .15s,color .15s;}
   .app-titlebar-hamburger:hover{background:var(--hover-bg);color:var(--text);}
@@ -2824,6 +2825,9 @@
     .app-titlebar-hamburger,.app-titlebar-spacer{display:flex;}
     .app-titlebar-new-chat,.app-titlebar-reload{display:inline-flex;width:44px;height:44px;}
     .app-titlebar-inner{flex:1 1 auto;}
+    .app-titlebar-title{max-width:72vw;}
+    .app-titlebar-sub{font-size:9px;padding:1px 5px;}
+    .app-titlebar-title.long-pressing{opacity:.6;transition:opacity .1s;}
     .system-health-panel.insights-card{gap:10px;padding:12px;}
     .system-health-head{align-items:flex-start;}
     .system-health-metrics{grid-template-columns:1fr;gap:8px;}
diff --git a/tests/test_app_titlebar_restore.py b/tests/test_app_titlebar_restore.py
index 155e3761a..f14830647 100644
--- a/tests/test_app_titlebar_restore.py
+++ b/tests/test_app_titlebar_restore.py
@@ -18,7 +18,7 @@ def test_app_titlebar_returns_to_centered_desktop_layout():
 
 
 def test_app_titlebar_subtitle_shows_message_count_again():
-    assert "subText = t('n_messages', vis.length);" in PANELS_JS
+    assert "subText = String(vis.length);" in PANELS_JS
 
 
 def test_queue_updates_do_not_hijack_app_titlebar_subtitle():
diff --git a/tests/test_mobile_titlebar_session_actions.py b/tests/test_mobile_titlebar_session_actions.py
new file mode 100644
index 000000000..95d447020
--- /dev/null
+++ b/tests/test_mobile_titlebar_session_actions.py
@@ -0,0 +1,26 @@
+"""Static regressions for mobile titlebar session title priority (#4520)."""
+import pathlib
+
+ROOT = pathlib.Path(__file__).parent.parent
+HTML = (ROOT / "static" / "index.html").read_text(encoding="utf-8")
+PANELS_JS = (ROOT / "static" / "panels.js").read_text(encoding="utf-8")
+
+
+def test_titlebar_title_element_exists():
+    assert 'id="appTitlebarTitle"' in HTML
+    assert 'id="appTitlebarSub"' in HTML
+
+
+def test_syncappTitlebar_compact_metadata():
+    assert 'subText = String(vis.length)' in PANELS_JS
+    assert "t('n_messages', vis.length)" not in PANELS_JS
+
+
+def test_long_press_handler_wired():
+    assert '_lpTimer' in PANELS_JS
+    assert 'SESSION_LONG_PRESS_DELAY_MS' in PANELS_JS
+    assert 'long-pressing' in PANELS_JS
+
+
+def test_session_action_menu_callable_from_titlebar():
+    assert '_openSessionActionMenu(S.session, titleEl)' in PANELS_JS