Imported from reason-machines/codex-skills (skills/heige-codex-skin-studio/SKILL.md). Install upstream with npx skills add reason-machines/codex-skills --skill heige-codex-skin-studio. Copyright stays with the author.

HeiGe Codex Skin Studio

Skill by ara.so — Codex Skills collection.

HeiGe Codex Skin Studio is a theme and skin switcher for OpenAI Codex Desktop (macOS/Windows) that injects custom CSS and backgrounds through Chrome DevTools Protocol (CDP) on loopback 127.0.0.1:9341. It does not modify app.asar, binaries, or signature resources. One image becomes a theme; a top menu (🎨) switches themes instantly and controls persistence across restarts.

What It Does

• 12 built-in themes: Hatsune Miku, Genshin Impact (2), Wuthering Waves (2), Naruto (2), Love and Deepspace (2), Dragon Ball (2), easter egg
• Custom image themes: Upload any PNG/JPG/WebP, auto-extracts color palette and generates dark/light variants
• Persistent skin: Optional launch agent (macOS LaunchAgent / Windows scheduled task) reapplies theme on every Codex restart
• Reading enhancement: 90% transparent adaptive background for replies, toggled in theme center
• AI-assisted theme creation: .skill file enables Codex to generate images and apply them as themes end-to-end

Installation

macOS

cd /path/to/heige-codex-skin-studio
open scripts/install.command

This installs the launcher and applies the default Miku theme. The 🎨 menu appears in Codex Desktop's top bar.

Windows

cd \path\to\heige-codex-skin-studio
scripts\windows\install.bat

For daily use, run scripts\windows\apply.ps1 or the compatibility alias scripts\windows\enable-skin.bat to restore the current session. To enable persistence (launch on login), use the 🎨 menu's "Persistent Skin" toggle.

Uninstall (Windows):

scripts\windows\uninstall.bat

Removes scheduled tasks, Start Menu shortcuts, AppData state, and stable installation directory.

Key Commands & Scripts

Command-line options (for apply.command / apply.ps1):

# macOS
./scripts/apply.command --restart        # Force quit Codex & relaunch with skin
./scripts/apply.command --theme miku     # Apply specific built-in theme
./scripts/apply.command --custom /path/to/image.png  # Apply custom image theme

# Windows (PowerShell)
.\scripts\windows\apply.ps1 -Restart
.\scripts\windows\apply.ps1 -Theme "genshin-night"
.\scripts\windows\apply.ps1 -CustomImage "C:\path\to\image.jpg"

Creating Custom Themes

Method 1: Top Menu Upload

1. Click 🎨 in Codex Desktop
2. Select ＋ Custom Image
3. Upload PNG/JPG/JPEG/WebP
4. Auto-extracts palette, generates light/dark variants
5. Theme is saved to user library and persists if "Persistent Skin" is enabled

Method 2: Command-Line Generator

# macOS
./customize.command

# Prompts for image path, generates theme in output/custom-theme/

Method 3: AI-Assisted (Codex Skill)

Install output/heige-codex-skin-studio.skill in Codex Desktop, then prompt:

"Generate a cyberpunk neon cityscape, then create a Codex theme from it"

Codex will generate the image, extract colors, and apply the theme automatically.

Theme JSON Format

Themes are stored in themes/<theme-name>/theme.json:

{
  "name": "Miku 488137",
  "author": "HeiGe AI",
  "version": "2.0.0",
  "description": "High-fidelity Hatsune Miku theme",
  "background": {
    "light": "miku-light.webp",
    "dark": "miku-dark.webp"
  },
  "colors": {
    "light": {
      "primary": "#39C5BB",
      "secondary": "#5DCECD",
      "accent": "#7FD9D8",
      "background": "#E8F8F8",
      "surface": "#FFFFFF",
      "text": "#1A1A1A",
      "textSecondary": "#666666",
      "border": "#D0E8E8"
    },
    "dark": {
      "primary": "#39C5BB",
      "secondary": "#2DB5B0",
      "accent": "#5DCECD",
      "background": "#0A1A1A",
      "surface": "#162828",
      "text": "#E8F8F8",
      "textSecondary": "#A0B8B8",
      "border": "#2D4848"
    }
  },
  "codexAppearance": {
    "light": "light",
    "dark": "dark"
  }
}

Key fields:

• background.light / background.dark: relative paths to background images
• colors.light / colors.dark: 8-color palette (primary, secondary, accent, background, surface, text, textSecondary, border)
• codexAppearance: maps theme mode to Codex's native light/dark setting

Configuration & Persistence

Persistent skin is controlled via the 🎨 menu toggle:

• macOS: Creates ~/Library/LaunchAgents/com.heigeai.codex-skin-controller.plist
• Windows: Creates scheduled task HeiGeAI_CodexSkinController for current user login

User theme library: Custom uploaded themes are stored in:

• macOS: ~/Library/Application Support/HeiGeCodexSkin/user-themes/
• Windows: %APPDATA%\HeiGeCodexSkin\user-themes\

State file (tracks current theme, persistence status):

• macOS: ~/Library/Application Support/HeiGeCodexSkin/skin-state.json
• Windows: %APPDATA%\HeiGeCodexSkin\skin-state.json

{
  "currentTheme": "miku",
  "persistenceEnabled": true,
  "readingEnhancement": true,
  "lastApplied": "2026-07-29T12:34:56.789Z"
}

Common Patterns

Apply a Built-in Theme Programmatically

// In src/injector/theme-manager.js (or your own script)
const ThemeManager = require('./src/injector/theme-manager.js');
const tm = new ThemeManager();

await tm.applyTheme('genshin-night'); // Built-in theme ID

Generate & Apply Custom Theme from Image

const { generateThemeFromImage } = require('./src/utils/theme-generator.js');
const ThemeManager = require('./src/injector/theme-manager.js');

const imagePath = '/path/to/wallpaper.jpg';
const outputDir = './output/my-custom-theme';

// Extract colors, generate theme.json + CSS
await generateThemeFromImage(imagePath, outputDir, {
  themeName: 'My Custom Theme',
  author: 'Your Name'
});

// Apply it
const tm = new ThemeManager();
await tm.applyTheme(outputDir); // Pass directory path for custom themes

Inject CSS Directly via CDP

const CDP = require('chrome-remote-interface');

const client = await CDP({ port: 9341 });
const { Page, Runtime } = client;

await Page.enable();
await Runtime.enable();

const css = `
  body {
    background-image: url('file:///path/to/bg.png');
    background-size: cover;
  }
  .chat-message {
    background-color: rgba(57, 197, 187, 0.9) !important;
  }
`;

await Runtime.evaluate({
  expression: `
    (function() {
      const style = document.createElement('style');
      style.id = 'heige-custom-skin';
      style.textContent = ${JSON.stringify(css)};
      document.head.appendChild(style);
    })();
  `
});

await client.close();

Read Current Theme State

const fs = require('fs');
const path = require('path');
const os = require('os');

const stateDir = process.platform === 'win32'
  ? path.join(process.env.APPDATA, 'HeiGeCodexSkin')
  : path.join(os.homedir(), 'Library', 'Application Support', 'HeiGeCodexSkin');

const statePath = path.join(stateDir, 'skin-state.json');
const state = JSON.parse(fs.readFileSync(statePath, 'utf-8'));

console.log('Current theme:', state.currentTheme);
console.log('Persistence enabled:', state.persistenceEnabled);

Toggle Reading Enhancement

// In injected context (via CDP Runtime.evaluate)
window.heigeReadingEnhancement = !window.heigeReadingEnhancement;

// Reload theme to apply
const themeId = document.documentElement.dataset.heigeTheme;
window.heigeApplyTheme(themeId);

Environment Variables

• HEIGE_CODEX_CDP_PORT — Override CDP port (default: 9341)
• HEIGE_CODEX_THEME_DIR — Custom theme directory (default: ./themes)
• HEIGE_LOG_LEVEL — debug | info | warn | error (default: info)

Example:

export HEIGE_CODEX_CDP_PORT=9342
export HEIGE_LOG_LEVEL=debug
./scripts/apply.command

Troubleshooting

Skin not appearing after restart

1. Check persistence is enabled: 🎨 menu → "Persistent Skin" should be green
2. Verify launch agent exists:
   • macOS: ls ~/Library/LaunchAgents/com.heigeai.codex-skin-controller.plist
   • Windows: schtasks /Query /TN HeiGeAI_CodexSkinController
3. Re-run install script

Codex window becomes sluggish (low FPS, input lag)

# macOS
./scripts/apply.command --restart

# Windows
.\scripts\windows\apply.ps1 -Restart

Force-quit and relaunch Codex with fresh CDP session.

Custom image theme not saving

• Ensure image is PNG/JPG/JPEG/WebP, <10MB
• Check user theme directory exists and is writable:
  • macOS: ~/Library/Application Support/HeiGeCodexSkin/user-themes/
  • Windows: %APPDATA%\HeiGeCodexSkin\user-themes\
• Review logs: tail -f ~/.heige-codex-skin.log (macOS) or %TEMP%\heige-codex-skin.log (Windows)

CDP connection refused

• Codex must be launched with --remote-debugging-port=9341
• Check Codex is running: ps aux | grep Codex (macOS) or tasklist | findstr Codex (Windows)
• Firewall/antivirus may block loopback port — whitelist 127.0.0.1:9341

"Persistent Skin" toggle stuck on "Waiting..."

• macOS: Check LaunchAgent plist syntax: plutil -lint ~/Library/LaunchAgents/com.heigeai.codex-skin-controller.plist
• Windows: Run schtasks /Query /TN HeiGeAI_CodexSkinController /V /FO LIST to verify task exists and is enabled
• Re-run install script to repair

Theme colors not matching preview

• Verify theme.json color keys are correct (primary, secondary, accent, background, surface, text, textSecondary, border)
• Check Codex's native appearance setting — theme applies codexAppearance.light or codexAppearance.dark to the app
• Some UI elements may use Codex's built-in styles — skin only overrides injected CSS

Uninstall doesn't remove all files

# macOS
rm -rf ~/Library/Application\ Support/HeiGeCodexSkin
rm ~/Library/LaunchAgents/com.heigeai.codex-skin-controller.plist
launchctl remove com.heigeai.codex-skin-controller

# Windows
schtasks /Delete /TN HeiGeAI_CodexSkinController /F
rd /s /q "%APPDATA%\HeiGeCodexSkin"
rd /s /q "%LOCALAPPDATA%\Programs\HeiGeCodexSkin"

Security Notes

• CDP on loopback (127.0.0.1:9341) has no authentication — any local process with same user privileges can connect
• Injection only occurs during local debugging session; native Codex signature is not modified
• Full security policy: SECURITY.md in project root
• Asset provenance (themes, images): ASSET_PROVENANCE.md

Real-World Example: AI-Driven Theme Pipeline

// Install the .skill file in Codex Desktop first:
// output/heige-codex-skin-studio.skill

// Then in Codex chat, prompt:
// "Generate a pastel sakura landscape, 1920x1080, then create a Codex theme"

// Codex will execute (simplified):
const { generateImage } = require('./src/ai/image-generator.js');
const { generateThemeFromImage } = require('./src/utils/theme-generator.js');
const ThemeManager = require('./src/injector/theme-manager.js');

async function aiThemePipeline(prompt) {
  // 1. Generate image via Codex's internal DALL-E
  const imagePath = await generateImage(prompt, {
    size: '1920x1080',
    outputPath: './output/ai-generated.png'
  });

  // 2. Extract palette and generate theme
  const themeDir = './output/sakura-theme';
  await generateThemeFromImage(imagePath, themeDir, {
    themeName: 'AI Sakura',
    author: 'Codex AI'
  });

  // 3. Apply theme
  const tm = new ThemeManager();
  await tm.applyTheme(themeDir);

  console.log('✅ AI-generated theme applied!');
}

aiThemePipeline('pastel sakura landscape with cherry blossoms at sunset');

License & Attribution

• Code: MIT License
• Assets: See ASSET_PROVENANCE.md for per-file sources and licensing
• Trademarks: Character/franchise assets (Miku, Genshin, etc.) are property of their respective owners; this project does not claim rights or grant licenses for redistribution

Tip: After installing, use the 🎨 menu in Codex Desktop for all theme operations. For programmatic control, import src/injector/theme-manager.js and call applyTheme(themeId).