diff --git a/packages/cli/src/ui/hooks/useTerminalTheme.ts b/packages/cli/src/ui/hooks/useTerminalTheme.ts
index e7e4826ecc..93b9bb48bc 100644
--- a/packages/cli/src/ui/hooks/useTerminalTheme.ts
+++ b/packages/cli/src/ui/hooks/useTerminalTheme.ts
@@ -6,7 +6,7 @@
 
 import { useEffect } from 'react';
 import { useStdout } from 'ink';
-import { parseX11Rgb, getLuminance } from '../themes/color-utils.js';
+import { getLuminance, parseColor } from '../themes/color-utils.js';
 import { themeManager, DEFAULT_THEME } from '../themes/theme-manager.js';
 import { DefaultLight } from '../themes/default-light.js';
 import { useSettings } from '../contexts/SettingsContext.js';
@@ -47,7 +47,7 @@ export function useTerminalTheme(
         );
       if (!match) return;
 
-      const hexColor = parseX11Rgb(match[1], match[2], match[3]);
+      const hexColor = parseColor(match[1], match[2], match[3]);
       const luminance = getLuminance(hexColor);
       config.setTerminalBackground(hexColor);
 
diff --git a/packages/cli/src/ui/themes/color-utils.test.ts b/packages/cli/src/ui/themes/color-utils.test.ts
index 0c00e5abe2..5e40abc9b0 100644
--- a/packages/cli/src/ui/themes/color-utils.test.ts
+++ b/packages/cli/src/ui/themes/color-utils.test.ts
@@ -12,8 +12,8 @@ import {
   CSS_NAME_TO_HEX_MAP,
   INK_SUPPORTED_NAMES,
   getThemeTypeFromBackgroundColor,
-  parseX11Rgb,
   getLuminance,
+  parseColor,
 } from './color-utils.js';
 
 describe('Color Utils', () => {
@@ -310,33 +310,33 @@ describe('Color Utils', () => {
     });
   });
 
-  describe('parseX11Rgb', () => {
+  describe('parseColor', () => {
     it('should parse 1-digit components', () => {
       // F/F/F => #ffffff
-      expect(parseX11Rgb('f', 'f', 'f')).toBe('#ffffff');
+      expect(parseColor('f', 'f', 'f')).toBe('#ffffff');
       // 0/0/0 => #000000
-      expect(parseX11Rgb('0', '0', '0')).toBe('#000000');
+      expect(parseColor('0', '0', '0')).toBe('#000000');
     });
 
     it('should parse 2-digit components', () => {
       // ff/ff/ff => #ffffff
-      expect(parseX11Rgb('ff', 'ff', 'ff')).toBe('#ffffff');
+      expect(parseColor('ff', 'ff', 'ff')).toBe('#ffffff');
       // 80/80/80 => #808080
-      expect(parseX11Rgb('80', '80', '80')).toBe('#808080');
+      expect(parseColor('80', '80', '80')).toBe('#808080');
     });
 
     it('should parse 4-digit components (standard X11)', () => {
       // ffff/ffff/ffff => #ffffff (65535/65535 * 255 = 255)
-      expect(parseX11Rgb('ffff', 'ffff', 'ffff')).toBe('#ffffff');
+      expect(parseColor('ffff', 'ffff', 'ffff')).toBe('#ffffff');
       // 0000/0000/0000 => #000000
-      expect(parseX11Rgb('0000', '0000', '0000')).toBe('#000000');
+      expect(parseColor('0000', '0000', '0000')).toBe('#000000');
       // 7fff/7fff/7fff => approx #7f7f7f (32767/65535 * 255 = 127.498... -> 127 -> 7f)
-      expect(parseX11Rgb('7fff', '7fff', '7fff')).toBe('#7f7f7f');
+      expect(parseColor('7fff', '7fff', '7fff')).toBe('#7f7f7f');
     });
 
     it('should handle mixed case', () => {
-      expect(parseX11Rgb('FFFF', 'FFFF', 'FFFF')).toBe('#ffffff');
-      expect(parseX11Rgb('Ffff', 'fFFF', 'ffFF')).toBe('#ffffff');
+      expect(parseColor('FFFF', 'FFFF', 'FFFF')).toBe('#ffffff');
+      expect(parseColor('Ffff', 'fFFF', 'ffFF')).toBe('#ffffff');
     });
   });
 });
diff --git a/packages/cli/src/ui/themes/color-utils.ts b/packages/cli/src/ui/themes/color-utils.ts
index 3d9f007f95..fed63b93ef 100644
--- a/packages/cli/src/ui/themes/color-utils.ts
+++ b/packages/cli/src/ui/themes/color-utils.ts
@@ -318,7 +318,7 @@ export function getLuminance(backgroundColor: string): number {
  * @param bHex Blue component as hex string
  * @returns Hex color string (e.g. #RRGGBB)
  */
-export function parseX11Rgb(rHex: string, gHex: string, bHex: string): string {
+export function parseColor(rHex: string, gHex: string, bHex: string): string {
   const parseComponent = (hex: string) => {
     const val = parseInt(hex, 16);
     if (hex.length === 1) return (val / 15) * 255;
diff --git a/packages/cli/src/ui/utils/terminalCapabilityManager.ts b/packages/cli/src/ui/utils/terminalCapabilityManager.ts
index b24647abe5..5b2b20a428 100644
--- a/packages/cli/src/ui/utils/terminalCapabilityManager.ts
+++ b/packages/cli/src/ui/utils/terminalCapabilityManager.ts
@@ -14,6 +14,7 @@ import {
   enableBracketedPasteMode,
   disableBracketedPasteMode,
 } from '@google/gemini-cli-core';
+import { parseColor } from '../themes/color-utils.js';
 
 export type TerminalBackgroundColor = string | undefined;
 
@@ -129,7 +130,7 @@ export class TerminalCapabilityManager {
           const match = buffer.match(TerminalCapabilityManager.OSC_11_REGEX);
           if (match) {
             bgReceived = true;
-            this.terminalBackgroundColor = this.parseColor(
+            this.terminalBackgroundColor = parseColor(
               match[1],
               match[2],
               match[3],
@@ -234,24 +235,6 @@ export class TerminalCapabilityManager {
   isKittyProtocolEnabled(): boolean {
     return this.kittyEnabled;
   }
-
-  private parseColor(rHex: string, gHex: string, bHex: string): string {
-    const parseComponent = (hex: string) => {
-      const val = parseInt(hex, 16);
-      if (hex.length === 1) return (val / 15) * 255;
-      if (hex.length === 2) return val;
-      if (hex.length === 3) return (val / 4095) * 255;
-      if (hex.length === 4) return (val / 65535) * 255;
-      return val;
-    };
-
-    const r = parseComponent(rHex);
-    const g = parseComponent(gHex);
-    const b = parseComponent(bHex);
-
-    const toHex = (c: number) => Math.round(c).toString(16).padStart(2, '0');
-    return `#${toHex(r)}${toHex(g)}${toHex(b)}`;
-  }
 }
 
 export const terminalCapabilityManager =