diff --git a/app/src/components/RootLayout.tsx b/app/src/components/RootLayout.tsx
index df5595124d..7f04c7048a 100644
--- a/app/src/components/RootLayout.tsx
+++ b/app/src/components/RootLayout.tsx
@@ -49,6 +49,13 @@ export function RootLayout() {
     window.scrollTo(0, 0);
   }, [pathname, hash, navigationType]);
 
+  // Always reset horizontal scroll on route change. If a previous page leaked
+  // page-level horizontal scroll (e.g. a wide table on mobile), the offset
+  // otherwise persists into the next page and clips its left edge.
+  useEffect(() => {
+    window.scrollTo({ left: 0, top: window.scrollY });
+  }, [pathname]);
+
   return (
     <Box sx={{
       display: 'flex',
diff --git a/app/src/pages/McpPage.tsx b/app/src/pages/McpPage.tsx
index 2650e91cc2..651505f4c7 100644
--- a/app/src/pages/McpPage.tsx
+++ b/app/src/pages/McpPage.tsx
@@ -28,6 +28,9 @@ const inlineCodeSx = {
   padding: '2px 6px',
   borderRadius: '3px',
   color: 'var(--ink)',
+  // Long URLs / commands sit in TableCells; without explicit wrapping they
+  // force the table wider than a mobile viewport.
+  overflowWrap: 'anywhere' as const,
 };
 
 export function McpPage() {
diff --git a/app/src/styles/tokens.css b/app/src/styles/tokens.css
index c1c01609f3..37be1675ea 100644
--- a/app/src/styles/tokens.css
+++ b/app/src/styles/tokens.css
@@ -62,6 +62,14 @@
 /* MonoLisa script variant (italic ss02) — test */
 html { font-feature-settings: "ss02"; }
 
+/* Defense-in-depth against page-level horizontal scroll on mobile. `clip`
+   (not `hidden`) so the masthead's `position: sticky` keeps working — `hidden`
+   would create a scroll container and break it. Wide elements still need their
+   own local containment (e.g. tables, code blocks); this just stops a stray
+   overflow from leaking into viewport-wide horizontal scroll, which on SPA
+   nav otherwise persists across routes. */
+html, body { overflow-x: clip; }
+
 /* Animations */
 @keyframes rise {
   from { opacity: 0; transform: translateY(8px); }