diff --git a/client/src/components/run/ChatAddMenu.tsx b/client/src/components/run/ChatAddMenu.tsx
index e1562cd8..0f002352 100644
--- a/client/src/components/run/ChatAddMenu.tsx
+++ b/client/src/components/run/ChatAddMenu.tsx
@@ -13,7 +13,8 @@
  * puts `/<name>` (`/<plugin>:<name>`) at the front of the message — the same
  * text the `/` autocomplete inserts, so the CLI runs it as typed. Both lists
  * are read when the menu first opens (`GET /api/cc-config/skills|plugins`),
- * and Manage opens the Claude config page on that tab.
+ * and Manage opens the Claude config page on that tab. The menu opens
+ * downward when the box sits too near the top to fit it above.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 
@@ -78,6 +79,35 @@ function loadLists(cwd: string): Promise<Lists> {
 
 const PANEL =
   "absolute w-60 rounded-xl border border-border bg-surface-1 py-1 shadow-lg animate-fade-in";
+/** Room the menu and its tallest submenu (Project files: search + list) need. */
+const MENU_ROOM = 380;
+
+/** The visible band the button sits in: the viewport, narrowed by any
+ * scrolling/clipping ancestor (the page body scrolls inside the layout). */
+function clipBand(el: HTMLElement): { top: number; bottom: number } {
+  let top = 0;
+  let bottom = window.innerHeight;
+  for (let p = el.parentElement; p; p = p.parentElement) {
+    const o = getComputedStyle(p);
+    if (/(auto|scroll|hidden|clip)/.test(o.overflowY + o.overflow)) {
+      const r = p.getBoundingClientRect();
+      top = Math.max(top, r.top);
+      bottom = Math.min(bottom, r.bottom);
+    }
+  }
+  return { top, bottom };
+}
+
+/** Open downward when there is not room above but more below. */
+function opensDown(el: HTMLElement | null): boolean {
+  if (!el) return false;
+  const r = el.getBoundingClientRect();
+  const band = clipBand(el);
+  const above = r.top - band.top;
+  const below = band.bottom - r.bottom;
+  return above < MENU_ROOM && below > above;
+}
+
 const ROW =
   "flex w-full items-center gap-2.5 px-3 py-1.5 text-left text-sm text-fg-secondary hover:bg-surface-3 hover:text-fg-primary";
 
@@ -195,6 +225,7 @@ export function ChatAddMenu({
   const { t } = useTranslation("run");
   const navigate = useNavigate();
   const [open, setOpen] = useState(false);
+  const [down, setDown] = useState(false);
   const [sub, setSub] = useState<Sub | null>(null);
   const [context, setContext] = useState<Attachment[] | null>(null);
   const [recent, setRecent] = useState<Attachment[]>([]);
@@ -286,6 +317,8 @@ export function ChatAddMenu({
         />
       ))
     );
+  // A submenu lines up with the menu's edge nearest the button.
+  const edge = down ? "top-0" : "bottom-0";
   const shownPlugin = lists?.plugins.find((p) => p.name === plugin);
 
   return (
@@ -296,13 +329,17 @@ export function ChatAddMenu({
         aria-label={t("chat.add")}
         title={t("chat.add")}
         aria-expanded={open}
-        onClick={() => (open ? close() : setOpen(true))}
+        onClick={() => {
+          if (open) return close();
+          setDown(opensDown(ref.current));
+          setOpen(true);
+        }}
         className="flex h-8 w-8 items-center justify-center rounded-full text-fg-muted transition-colors hover:bg-surface-3 hover:text-fg-primary"
       >
         <Plus className="h-4 w-4" />
       </button>
       {open && (
-        <div role="menu" data-testid="chat-add-menu" className={`${PANEL} bottom-full left-0 mb-2`}>
+        <div role="menu" data-testid="chat-add-menu" className={`${PANEL} left-0 ${down ? "top-full mt-2" : "bottom-full mb-2"}`}>
           <Row
             icon={<Paperclip className="h-4 w-4" />}
             label={t("chat.upload")}
@@ -376,13 +413,13 @@ export function ChatAddMenu({
           )}
 
           {sub === "project" && (
-            <div role="menu" className={`${PANEL} bottom-0 left-full ml-1 w-72 pt-2`}>
+            <div role="menu" className={`${PANEL} ${edge} left-full ml-1 w-72 pt-2`}>
               <ProjectFiles cwd={cwd} onPick={(rel) => attach(projectAttachment(rel))} />
             </div>
           )}
 
           {(sub === "context" || sub === "recent") && (
-            <div role="menu" className={`${PANEL} bottom-0 left-full ml-1`}>
+            <div role="menu" className={`${PANEL} ${edge} left-full ml-1`}>
               <div className="max-h-72 overflow-y-auto">
                 {(sub === "context" ? context : recent)?.length ? (
                   (sub === "context" ? context! : recent).map((it) => (
@@ -405,7 +442,7 @@ export function ChatAddMenu({
           )}
 
           {sub === "skills" && (
-            <div role="menu" className={`${PANEL} bottom-0 left-full ml-1`}>
+            <div role="menu" className={`${PANEL} ${edge} left-full ml-1`}>
               <div className="max-h-72 overflow-y-auto">{entries(lists?.skills ?? [], "")}</div>
               <div className="my-1 border-t border-border" />
               <Row
@@ -417,7 +454,7 @@ export function ChatAddMenu({
           )}
 
           {sub === "plugins" && (
-            <div role="menu" className={`${PANEL} bottom-0 left-full ml-1`}>
+            <div role="menu" className={`${PANEL} ${edge} left-full ml-1`}>
               <div className="max-h-72 overflow-y-auto">
                 {lists && lists.plugins.length === 0 && (
                   <p className="px-3 py-1.5 text-xs text-fg-muted">{t("chat.none")}</p>
@@ -443,7 +480,7 @@ export function ChatAddMenu({
                 onClick={() => manage("plugins")}
               />
               {shownPlugin && (
-                <div role="menu" className={`${PANEL} bottom-0 left-full ml-1`}>
+                <div role="menu" className={`${PANEL} ${edge} left-full ml-1`}>
                   <div className="max-h-72 overflow-y-auto">
                     {entries(
                       shownPlugin.items,