Codex++

Codex++ lets you install local tweaks into the OpenAI Codex desktop app. Tweaks can change UI, add settings pages, run main-process code, and use native OS-level features through the Codex++ bridge. Join the Discord community.

Unofficial project. Not affiliated with OpenAI. Use at your own risk.

TL;DR

Codex++ patches your local Codex app so Codex loads a small Codex++ runtime on startup.

That runtime lives in your user data directory, not inside Codex. It finds tweaks in a local tweaks/ folder and loads them when Codex opens.

The app patch is tiny. Your tweaks, config, logs, backups, and runtime files stay outside the app bundle, so you can edit tweaks without rebuilding Codex.

When Codex updates, the patch is usually removed. Codex++ installs a watcher that notices this and re-applies the patch.

1.0.0 adds cleaner patching, better debug output, Owl runtime detection, browser-host debugging, and native bridge support for AppKit, Metal, helper processes, and tweak-owned native modules.

Table Of Contents

• Install
• What Codex++ Is
• How It Works
• Common Commands
• Where Files Live
• Writing Tweaks
• Owl And Native Bridge
• Browser Host Mode
• Updates And Recovery
• Security
• More Docs

Install

Agentic install, from Codex:

Inspect and install this for me: https://github.com/b-nnett/codex-plusplus
Tell me where you install it and send me the local path for adding new tweaks.

Homebrew:

brew install b-nnett/codex-plusplus/codexplusplus
codexplusplus install

GitHub source installer:

curl -fsSL https://raw.githubusercontent.com/b-nnett/codex-plusplus/main/install.sh | bash

Windows PowerShell:

irm https://raw.githubusercontent.com/b-nnett/codex-plusplus/main/install.ps1 | iex

Bun:

bun install -g github:b-nnett/codex-plusplus
codexplusplus install

After install, launch Codex normally. Open Settings and look for the Codex++ section.

What Codex++ Is

Codex++ is a tweak loader for Codex Desktop.

It gives you:

• A local tweaks/ folder.
• A runtime that loads renderer and main-process tweaks.
• A Codex++ Settings section inside Codex.
• CLI tools for install, repair, update, debug, and tweak development.
• A watcher that repairs Codex++ after Codex updates.
• A public SDK for tweak authors.
• Native bridge APIs for advanced macOS tweaks.

It does not replace Codex, proxy your account, or run a separate Codex clone. It modifies your installed app so it can load local code.

How It Works

Install flow:

1. Codex++ finds your Codex app.
2. It backs up the unpatched app files.
3. It patches Codex app.asar so a Codex++ loader runs first.
4. It stages the Codex++ runtime in your user data directory.
5. It re-signs the app when needed.
6. It installs a watcher for future Codex updates.

Runtime flow:

1. You launch Codex.
2. The Codex++ loader starts.
3. The loader starts the Codex++ runtime from disk.
4. Codex starts normally.
5. Codex++ discovers enabled tweaks.
6. Renderer tweaks run in Codex windows.
7. Main-process tweaks run in the Codex main process.
8. The Settings UI shows Codex++ pages and tweak controls.

Common Commands

Tweak development commands:

Source checkout commands:

npm run build
npm test
node packages/installer/dist/cli.js install
node packages/installer/dist/cli.js debug

Where Files Live

Codex++ keeps almost everything outside Codex.

Default user data paths:

On Windows Store installs, Codex++ also creates a writable managed app copy under %LOCALAPPDATA%/codex-plusplus/store-apps/. Use the Codex++ shortcut for that copy.

Writing Tweaks

A tweak is a folder with a manifest and an entry file:

my-tweak/
  manifest.json
  index.js

Minimal manifest.json:

{
  "id": "com.you.my-tweak",
  "name": "My Tweak",
  "version": "0.1.0",
  "githubRepo": "you/my-tweak",
  "description": "Adds a Codex++ settings page.",
  "scope": "renderer",
  "main": "index.js"
}

Minimal index.js:

module.exports = {
  start(api) {
    api.settings.registerPage({
      id: "main",
      title: api.manifest.name,
      render(root) {
        root.textContent = "Hello from Codex++.";
      },
    });
  },
  stop() {},
};

Local dev loop:

codexplusplus create-tweak ./my-tweak --id com.you.my-tweak --name "My Tweak"
codexplusplus validate-tweak ./my-tweak
codexplusplus dev ./my-tweak

Full docs are in Writing Tweaks.

Owl And Native Bridge

Current macOS Codex builds use Owl: a native app shell with Chromium and an Electron-compatible JavaScript runtime.

Codex++ 1.0.0 detects Owl and reports capability status through:

codexplusplus debug

Tweak authors should use the Codex++ SDK, not raw Owl internals:

• api.codex.runtime.getInfo()
• api.codex.runtime.getCapabilities()
• api.codex.windows.*
• api.codex.cdp.*
• api.codex.native.*

Native bridge support includes:

• Tweak-owned .node modules.
• Objective-C++/N-API shims for Swift, AppKit, Metal, and MetalKit.
• Native child panels.
• Metal-backed child-window overlays.
• Helper processes.

Start with Native Bridge.

Browser Host Mode

Browser host mode opens the Codex React UI in a normal browser tab while a hidden Codex window provides the private app bridge:

codexplusplus browser --port 8765

Then open:

http://127.0.0.1:8765/

This is useful for debugging and browser automation. It is experimental. The in-app browser uses iframe shims in this mode, so some websites may block embedding.

Updates And Recovery

Update Codex++:

codexplusplus update

Run the official Codex updater on macOS:

codexplusplus update-codex

Repair Codex++:

codexplusplus repair --force

Disable tweaks temporarily:

codexplusplus safe-mode

Re-enable normal tweak loading:

codexplusplus safe-mode --off

Uninstall:

codexplusplus uninstall

Clean uninstall, including tweaks/config/logs/backups:

codexplusplus uninstall --purge

Security

Codex++ runs local code inside your Codex desktop app. Install tweaks only from sources you trust.

Important details:

• Codex++ does not silently update tweak files.
• Tweak update checks link to GitHub Releases for review.
• Native tweaks can run native code and need extra review.
• Native bridge paths are restricted to files inside the tweak directory.
• Tweak data APIs default to Codex++'s user data directory.

See Security.

More Docs

• Architecture
• Troubleshooting
• Writing Tweaks
• Tweak API Reference
• Manifest Reference
• Runtime And Lifecycle
• UI And DOM Patterns
• MCP Servers
• Owl Runtime Surface
• Owl Bridge Roadmap

Contributors

• Alex Naidis (@TheCrazyLex) - macOS permission hardening and sudo install handling.

License

MIT.