diff --git a/packages/cli/src/ui/components/ThemeDialog.tsx b/packages/cli/src/ui/components/ThemeDialog.tsx
index f04ae5172a..b62f83532c 100644
--- a/packages/cli/src/ui/components/ThemeDialog.tsx
+++ b/packages/cli/src/ui/components/ThemeDialog.tsx
@@ -365,7 +365,7 @@ def fibonacci(n):
                     availableHeight:
                       isAlternateBuffer === false ? codeBlockHeight : undefined,
                     maxWidth: colorizeCodeWidth,
-                    settings,
+                    settings: settings.merged,
                   })}
                   <Box marginTop={1} />
                   <DiffRenderer
diff --git a/packages/cli/src/ui/components/messages/DiffRenderer.tsx b/packages/cli/src/ui/components/messages/DiffRenderer.tsx
index b2f053e24e..dddf705954 100644
--- a/packages/cli/src/ui/components/messages/DiffRenderer.tsx
+++ b/packages/cli/src/ui/components/messages/DiffRenderer.tsx
@@ -170,7 +170,7 @@ export const DiffRenderer: React.FC<DiffRendererProps> = ({
         availableHeight: availableTerminalHeight,
         maxWidth: terminalWidth,
         theme,
-        settings,
+        settings: settings.merged,
         disableColor,
       });
     } else {
diff --git a/packages/cli/src/ui/hooks/useAlternateBuffer.ts b/packages/cli/src/ui/hooks/useAlternateBuffer.ts
index 45b387173a..445ecf8bca 100644
--- a/packages/cli/src/ui/hooks/useAlternateBuffer.ts
+++ b/packages/cli/src/ui/hooks/useAlternateBuffer.ts
@@ -5,10 +5,14 @@
  */
 
 import { useSettings } from '../contexts/SettingsContext.js';
-import type { LoadedSettings } from '../../config/settings.js';
+import type { LoadedSettings, MergedSettings } from '../../config/settings.js';
 
-export const isAlternateBufferEnabled = (settings: LoadedSettings): boolean =>
-  settings.merged.ui.useAlternateBuffer === true;
+export const isAlternateBufferEnabled = (
+  settings: LoadedSettings | MergedSettings,
+): boolean => {
+  const merged = 'merged' in settings ? settings.merged : settings;
+  return merged.ui.useAlternateBuffer === true;
+};
 
 export const useAlternateBuffer = (): boolean => {
   const settings = useSettings();
diff --git a/packages/cli/src/ui/utils/CodeColorizer.test.tsx b/packages/cli/src/ui/utils/CodeColorizer.test.tsx
index 94913c88bf..a256d68838 100644
--- a/packages/cli/src/ui/utils/CodeColorizer.test.tsx
+++ b/packages/cli/src/ui/utils/CodeColorizer.test.tsx
@@ -31,7 +31,7 @@ describe('colorizeCode', () => {
       code,
       language: 'javascript',
       maxWidth: 80,
-      settings,
+      settings: settings.merged,
       hideLineNumbers: true,
     });
 
diff --git a/packages/cli/src/ui/utils/CodeColorizer.tsx b/packages/cli/src/ui/utils/CodeColorizer.tsx
index 8a4233213e..76a4206d01 100644
--- a/packages/cli/src/ui/utils/CodeColorizer.tsx
+++ b/packages/cli/src/ui/utils/CodeColorizer.tsx
@@ -20,7 +20,7 @@ import {
   MaxSizedBox,
   MINIMUM_MAX_HEIGHT,
 } from '../components/shared/MaxSizedBox.js';
-import type { LoadedSettings } from '../../config/settings.js';
+import type { MergedSettings } from '../../config/settings.js';
 import { debugLogger } from '@google/gemini-cli-core';
 import { isAlternateBufferEnabled } from '../hooks/useAlternateBuffer.js';
 
@@ -131,7 +131,7 @@ export interface ColorizeCodeOptions {
   availableHeight?: number;
   maxWidth: number;
   theme?: Theme | null;
-  settings: LoadedSettings;
+  settings: MergedSettings;
   hideLineNumbers?: boolean;
   disableColor?: boolean;
 }
@@ -154,9 +154,7 @@ export function colorizeCode({
 }: ColorizeCodeOptions): React.ReactNode {
   const codeToHighlight = code.replace(/\n$/, '');
   const activeTheme = theme || themeManager.getActiveTheme();
-  const showLineNumbers = hideLineNumbers
-    ? false
-    : settings.merged.ui.showLineNumbers;
+  const showLineNumbers = hideLineNumbers ? false : settings.ui.showLineNumbers;
 
   const useMaxSizedBox = !isAlternateBufferEnabled(settings);
   try {
diff --git a/packages/cli/src/ui/utils/MarkdownDisplay.tsx b/packages/cli/src/ui/utils/MarkdownDisplay.tsx
index 60f15e9598..92bacbf88e 100644
--- a/packages/cli/src/ui/utils/MarkdownDisplay.tsx
+++ b/packages/cli/src/ui/utils/MarkdownDisplay.tsx
@@ -49,7 +49,7 @@ const MarkdownDisplayInternal: React.FC<MarkdownDisplayProps> = ({
       language: 'markdown',
       availableHeight: isAlternateBuffer ? undefined : availableTerminalHeight,
       maxWidth: terminalWidth - CODE_BLOCK_PREFIX_PADDING,
-      settings,
+      settings: settings.merged,
       hideLineNumbers: true,
     });
     return (
@@ -365,7 +365,7 @@ const RenderCodeBlockInternal: React.FC<RenderCodeBlockProps> = ({
         language: lang,
         availableHeight: availableTerminalHeight,
         maxWidth: terminalWidth - CODE_BLOCK_PREFIX_PADDING,
-        settings,
+        settings: settings.merged,
       });
       return (
         <Box paddingLeft={CODE_BLOCK_PREFIX_PADDING} flexDirection="column">
@@ -382,7 +382,7 @@ const RenderCodeBlockInternal: React.FC<RenderCodeBlockProps> = ({
     language: lang,
     availableHeight: isAlternateBuffer ? undefined : availableTerminalHeight,
     maxWidth: terminalWidth - CODE_BLOCK_PREFIX_PADDING,
-    settings,
+    settings: settings.merged,
   });
 
   return (