diff --git a/cli/src/components/choice-ad-banner.tsx b/cli/src/components/choice-ad-banner.tsx
index e25bc5076..3eaaebbf7 100644
--- a/cli/src/components/choice-ad-banner.tsx
+++ b/cli/src/components/choice-ad-banner.tsx
@@ -14,7 +14,7 @@ interface ChoiceAdBannerProps {
   onImpression?: (impUrl: string) => void
 }
 
-const CARD_HEIGHT = 5 // border-top + 2 lines description + spacer + cta row + border-bottom
+export const CHOICE_AD_BANNER_HEIGHT = 5 // border-top + 2 lines description + spacer + cta row + border-bottom
 const MAX_DESC_LINES = 2
 const MIN_CARD_WIDTH = 60 // Minimum width per ad card to remain readable
 
@@ -121,7 +121,7 @@ export const ChoiceAdBanner: React.FC<ChoiceAdBannerProps> = ({ ads, onImpressio
               onMouseOut={() => setHoveredIndex(null)}
               style={{
                 width: widths[i],
-                height: CARD_HEIGHT,
+                height: CHOICE_AD_BANNER_HEIGHT,
                 borderStyle: 'single',
                 borderColor: isHovered ? hoverBorderColor : theme.muted,
                 customBorderChars: BORDER_CHARS,
diff --git a/cli/src/components/waiting-room-screen.tsx b/cli/src/components/waiting-room-screen.tsx
index 3aa0f99d4..a87980905 100644
--- a/cli/src/components/waiting-room-screen.tsx
+++ b/cli/src/components/waiting-room-screen.tsx
@@ -3,7 +3,10 @@ import { useRenderer } from '@opentui/react'
 import React, { useMemo, useState } from 'react'
 
 import { Button } from './button'
-import { ChoiceAdBanner } from './choice-ad-banner'
+import {
+  ChoiceAdBanner,
+  CHOICE_AD_BANNER_HEIGHT,
+} from './choice-ad-banner'
 import { FreebuffModelSelector } from './freebuff-model-selector'
 import { ShimmerText } from './shimmer-text'
 import { useFreebuffCtrlCExit } from '../hooks/use-freebuff-ctrl-c-exit'
@@ -368,19 +371,21 @@ export const WaitingRoomScreen: React.FC<WaitingRoomScreenProps> = ({
         </box>
       </box>
 
-      {/* Ad banner pinned to the bottom, same look-and-feel as in chat. */}
-      {ads && (
-        <box style={{ flexShrink: 0 }}>
+      {/* Reserve the ad banner slot before the async ad fetch resolves so the
+          waiting-room content does not jump when the banner fills. */}
+      <box
+        style={{
+          width: '100%',
+          flexShrink: 0,
+          height: CHOICE_AD_BANNER_HEIGHT,
+        }}
+      >
+        {ads ? (
           <ChoiceAdBanner ads={ads} onImpression={recordImpression} />
-        </box>
-      )}
-
-      {/* Horizontal separator (mirrors chat input divider style) */}
-      {!ads && (
-        <text style={{ fg: theme.muted, flexShrink: 0 }}>
-          {'─'.repeat(terminalWidth)}
-        </text>
-      )}
+        ) : (
+          <text style={{ fg: theme.muted }}>{'─'.repeat(terminalWidth)}</text>
+        )}
+      </box>
     </box>
   )
 }