diff --git a/lib/livebook_web/live/output.ex b/lib/livebook_web/live/output.ex
index 31b1763bc..93057b7fc 100644
--- a/lib/livebook_web/live/output.ex
+++ b/lib/livebook_web/live/output.ex
@@ -94,7 +94,7 @@ defmodule LivebookWeb.Output do
     assigns = %{formatted: formatted, is_standalone: Livebook.Runtime.standalone?(runtime)}
 
     ~H"""
-    <div class="flex flex-col space-y-4">
+    <div class="flex flex-col space-y-4" role="complementary" aria-label="runtime restart required">
       <%= render_error(@formatted) %>
       <%= if @is_standalone do %>
         <div>
@@ -142,7 +142,7 @@ defmodule LivebookWeb.Output do
     assigns = %{message: message}
 
     ~H"""
-    <div class="whitespace-pre-wrap font-editor text-gray-500"><%= ansi_string_to_html(@message) %></div>
+    <div class="whitespace-pre-wrap font-editor text-gray-500" role="complementary" aria-label="error"><%= ansi_string_to_html(@message) %></div>
     """
   end
 
@@ -150,7 +150,7 @@ defmodule LivebookWeb.Output do
     assigns = %{message: message}
 
     ~H"""
-    <div class="whitespace-pre-wrap font-editor text-red-600"><%= @message %></div>
+    <div class="whitespace-pre-wrap font-editor text-red-600" role="complementary" aria-label="error message"><%= @message %></div>
     """
   end
 end
diff --git a/lib/livebook_web/live/session_live/cell_component.ex b/lib/livebook_web/live/session_live/cell_component.ex
index 9194027d0..341de0831 100644
--- a/lib/livebook_web/live/session_live/cell_component.ex
+++ b/lib/livebook_web/live/session_live/cell_component.ex
@@ -137,6 +137,7 @@ defmodule LivebookWeb.SessionLive.CellComponent do
     <.cell_body>
       <.editor cell_view={@cell_view} />
       <div class="flex flex-col"
+        aria-live="polite"
         data-element="outputs-container"
         id={"outputs-#{@cell_view.id}-#{@cell_view.outputs_batch_number}"}
         phx-update="append">