diff --git a/artifacts/tx-os/src/components/notes/folders-rail.tsx b/artifacts/tx-os/src/components/notes/folders-rail.tsx
index b40e4925..42626984 100644
--- a/artifacts/tx-os/src/components/notes/folders-rail.tsx
+++ b/artifacts/tx-os/src/components/notes/folders-rail.tsx
@@ -20,6 +20,16 @@ import {
   DropdownMenuItem,
   DropdownMenuTrigger,
 } from "@/components/ui/dropdown-menu";
+import {
+  AlertDialog,
+  AlertDialogAction,
+  AlertDialogCancel,
+  AlertDialogContent,
+  AlertDialogDescription,
+  AlertDialogFooter,
+  AlertDialogHeader,
+  AlertDialogTitle,
+} from "@/components/ui/alert-dialog";
 import {
   type NoteFolder,
   useCreateFolder,
@@ -136,6 +146,7 @@ export function FoldersRail({
   const [editingId, setEditingId] = useState<number | null>(null);
   const [editingName, setEditingName] = useState("");
   const [hoverTarget, setHoverTarget] = useState<string | null>(null);
+  const [pendingDelete, setPendingDelete] = useState<NoteFolder | null>(null);
   const create = useCreateFolder();
   const update = useUpdateFolder();
   const del = useDeleteFolder();
@@ -409,27 +420,7 @@ export function FoldersRail({
                         {t("notes.folders.rename", "Rename folder")}
                       </DropdownMenuItem>
                       <DropdownMenuItem
-                        onSelect={() => {
-                          if (
-                            confirm(
-                              t(
-                                "notes.folders.deleteConfirm",
-                                "Delete this folder? Notes inside will move to Unfiled.",
-                              ),
-                            )
-                          ) {
-                            del.mutate(f.id, {
-                              onSuccess: () => {
-                                if (
-                                  selected.kind === "folder" &&
-                                  selected.id === f.id
-                                ) {
-                                  onSelect({ kind: "all" });
-                                }
-                              },
-                            });
-                          }
-                        }}
+                        onSelect={() => setPendingDelete(f)}
                         className="text-red-600 focus:text-red-600"
                         data-testid={`folder-delete-${f.id}`}
                       >
@@ -492,6 +483,75 @@ export function FoldersRail({
           "Drag a note onto a folder to move it.",
         )}
       </div>
+
+      <AlertDialog
+        open={pendingDelete !== null}
+        onOpenChange={(open) => {
+          if (!open) setPendingDelete(null);
+        }}
+      >
+        <AlertDialogContent
+          data-testid={
+            pendingDelete
+              ? `folder-delete-dialog-${pendingDelete.id}`
+              : "folder-delete-dialog"
+          }
+        >
+          <AlertDialogHeader>
+            <AlertDialogTitle>
+              {t("notes.folders.deleteTitle", "Delete this folder?")}
+            </AlertDialogTitle>
+            <AlertDialogDescription>
+              {t(
+                "notes.folders.deleteConfirm",
+                "Delete this folder? Notes inside will move to Unfiled.",
+              )}
+            </AlertDialogDescription>
+          </AlertDialogHeader>
+          <AlertDialogFooter>
+            <AlertDialogCancel
+              data-testid={
+                pendingDelete
+                  ? `folder-delete-cancel-${pendingDelete.id}`
+                  : "folder-delete-cancel"
+              }
+            >
+              {t("common.cancel", "Cancel")}
+            </AlertDialogCancel>
+            <AlertDialogAction
+              className="bg-red-600 text-white hover:bg-red-700 focus:ring-red-600"
+              data-testid={
+                pendingDelete
+                  ? `folder-delete-confirm-${pendingDelete.id}`
+                  : "folder-delete-confirm"
+              }
+              onClick={() => {
+                const target = pendingDelete;
+                if (!target) return;
+                del.mutate(target.id, {
+                  onSuccess: () => {
+                    if (
+                      selected.kind === "folder" &&
+                      selected.id === target.id
+                    ) {
+                      onSelect({ kind: "all" });
+                    }
+                  },
+                  onError: (e) =>
+                    reportFolderError(
+                      e,
+                      "notes.folders.deleteFailed",
+                      "Could not delete folder",
+                    ),
+                });
+                setPendingDelete(null);
+              }}
+            >
+              {t("notes.folders.deleteAction", "Delete")}
+            </AlertDialogAction>
+          </AlertDialogFooter>
+        </AlertDialogContent>
+      </AlertDialog>
     </aside>
   );
 }
diff --git a/artifacts/tx-os/src/locales/ar.json b/artifacts/tx-os/src/locales/ar.json
index 0e8c91a8..d4540e17 100644
--- a/artifacts/tx-os/src/locales/ar.json
+++ b/artifacts/tx-os/src/locales/ar.json
@@ -1047,7 +1047,10 @@
       "unfiled": "بدون مجلد",
       "rename": "إعادة تسمية المجلد",
       "delete": "حذف المجلد",
+      "deleteTitle": "حذف هذا المجلد؟",
+      "deleteAction": "حذف",
       "deleteConfirm": "حذف هذا المجلد؟ ستنتقل الملاحظات بداخله إلى \"بدون مجلد\".",
+      "deleteFailed": "تعذّر حذف المجلد",
       "dragHint": "اسحب ملاحظة إلى هنا",
       "moved": "تم نقل الملاحظة"
     },
diff --git a/artifacts/tx-os/src/locales/en.json b/artifacts/tx-os/src/locales/en.json
index 30126e8c..d565c6be 100644
--- a/artifacts/tx-os/src/locales/en.json
+++ b/artifacts/tx-os/src/locales/en.json
@@ -948,7 +948,10 @@
       "unfiled": "Unfiled",
       "rename": "Rename folder",
       "delete": "Delete folder",
+      "deleteTitle": "Delete this folder?",
+      "deleteAction": "Delete",
       "deleteConfirm": "Delete this folder? Notes inside will move to Unfiled.",
+      "deleteFailed": "Could not delete folder",
       "dragHint": "Drag a note here",
       "moved": "Note moved"
     },
diff --git a/artifacts/tx-os/tests/notes-folders.spec.mjs b/artifacts/tx-os/tests/notes-folders.spec.mjs
index b8af2c56..2e84357e 100644
--- a/artifacts/tx-os/tests/notes-folders.spec.mjs
+++ b/artifacts/tx-os/tests/notes-folders.spec.mjs
@@ -285,7 +285,6 @@ test("create folder, drag note in, filter, move between folders, rename, delete"
     page.getByTestId(`folder-drop-${personal.id}-count`),
   ).toHaveText(/^1$/);
 
-  page.once("dialog", (d) => d.accept());
   const deletePromise = page.waitForResponse(
     (r) =>
       new URL(r.url()).pathname === `/api/note-folders/${personal.id}` &&
@@ -295,7 +294,12 @@ test("create folder, drag note in, filter, move between folders, rename, delete"
   );
   await page.getByTestId(`folder-menu-${personal.id}`).click();
   await page.getByTestId(`folder-delete-${personal.id}`).click();
+  // In-app AlertDialog (replacing native window.confirm) — click confirm.
+  await page.getByTestId(`folder-delete-confirm-${personal.id}`).click();
   await deletePromise;
+  await expect(
+    page.getByTestId(`folder-delete-dialog-${personal.id}`),
+  ).toHaveCount(0);
   await expect(page.getByTestId(`folder-select-${personal.id}`)).toHaveCount(0);
 
   // The orphaned note should have folderId reset to null via FK SET NULL,