diff --git a/src/theme_nerv_fx.py b/src/theme_nerv_fx.py
index e6a94c4..919bffe 100644
--- a/src/theme_nerv_fx.py
+++ b/src/theme_nerv_fx.py
@@ -18,3 +18,21 @@ class StatusFlicker:
  def get_alpha(self) -> float:
   # Modulate between 0.7 and 1.0 using sin wave
   return 0.85 + 0.15 * math.sin(time.time() * 20.0)
+
+class AlertPulsing:
+ def __init__(self):
+  self.active = False
+
+ def update(self, status: str):
+  self.active = status.lower().startswith("error")
+
+ def render(self, width: float, height: float):
+  if not self.active:
+   return
+  draw_list = imgui.get_foreground_draw_list()
+  # sin(t) is between -1 and 1
+  # scale to 0 to 1: (sin(t) + 1) / 2
+  # multiply by (0.2 - 0.05) = 0.15 and add 0.05
+  alpha = 0.05 + 0.15 * ((math.sin(time.time() * 4.0) + 1.0) / 2.0)
+  color = imgui.get_color_u32((1.0, 0.0, 0.0, alpha))
+  draw_list.add_rect((0.0, 0.0), (width, height), color, 0.0, 0, 10.0)
diff --git a/tests/test_theme_nerv_alert.py b/tests/test_theme_nerv_alert.py
new file mode 100644
index 0000000..b6c3eb5
--- /dev/null
+++ b/tests/test_theme_nerv_alert.py
@@ -0,0 +1,50 @@
+import pytest
+from unittest.mock import MagicMock, patch
+from imgui_bundle import imgui
+from src.theme_nerv_fx import AlertPulsing
+
+def test_alert_pulsing_update():
+ ap = AlertPulsing()
+ assert ap.active is False
+ 
+ ap.update("error: something failed")
+ assert ap.active is True
+ 
+ ap.update("ok: all good")
+ assert ap.active is False
+ 
+ ap.update("Error: Case Insensitive")
+ assert ap.active is True
+
+def test_alert_pulsing_render_inactive():
+ ap = AlertPulsing()
+ ap.active = False
+ 
+ with patch("src.theme_nerv_fx.imgui.get_foreground_draw_list") as mock_get_draw_list:
+  ap.render(100.0, 100.0)
+  mock_get_draw_list.assert_not_called()
+
+def test_alert_pulsing_render_active():
+ ap = AlertPulsing()
+ ap.active = True
+ 
+ mock_draw_list = MagicMock()
+ with patch("src.theme_nerv_fx.imgui.get_foreground_draw_list", return_value=mock_draw_list) as mock_get_draw_list, \
+      patch("src.theme_nerv_fx.imgui.get_color_u32", return_value=0xFF0000FF) as mock_get_color, \
+      patch("time.time", return_value=1.0):
+  
+  ap.render(800.0, 600.0)
+  
+  mock_get_draw_list.assert_called_once()
+  mock_get_color.assert_called_once()
+  mock_draw_list.add_rect.assert_called_once()
+  
+  # Check arguments of add_rect
+  # add_rect(p_min, p_max, col, rounding, flags, thickness)
+  args, kwargs = mock_draw_list.add_rect.call_args
+  assert args[0] == (0.0, 0.0)
+  assert args[1] == (800.0, 600.0)
+  assert args[2] == 0xFF0000FF
+  assert args[3] == 0.0
+  assert args[4] == 0
+  assert args[5] == 10.0