App: add Use Option as Meta for the integrated terminal on macOS

What variant of Codex are you using?

App (ChatGPT desktop / Codex desktop) on macOS

What feature would you like to see?

Please add a setting so the integrated terminal can treat the Option key as Meta, like Terminal.app’s Use Option as Meta key and iTerm2 / Ghostty / VS Code (terminal.integrated.macOptionIsMeta).

Use case. On macOS, Option is the usual Meta stand-in for readline / Emacs / zsh / fish bindings:

• Option+F / Option+B — forward / backward word
• Option+Backspace / Option+D — kill previous / next word
• Option+. — insert last argument

Those chords are muscle memory in every other terminal I use. In Codex’s integrated terminal they currently type macOS Option characters (ƒ, ∫, …) instead of sending Meta / ESC sequences to the PTY.

Current behavior. The app’s terminal settings only cover:

• default terminal location (bottom / right)
• integrated terminal shell

Settings > Keyboard Shortcuts remaps app commands, not PTY input. There is no Option-as-Meta toggle in the UI or in ~/.codex/config.toml.

The integrated terminal is xterm.js. xterm already has macOptionIsMeta (default false). The app constructs the terminal with font / cursor / theme options and does not pass macOptionIsMeta, so Option stays a third-level shift.

Suggested behavior.

1. Add a macOS-only setting, e.g. Use Option as Meta key, under General / terminal settings.
2. Persist it (same store as defaultTerminalLocation is fine).
3. When creating or updating the xterm instance, set macOptionIsMeta from that setting and apply it to already-open tabs.
4. Document the tradeoff: enabling it disables Option-based special-character input (ø, é, …) in that terminal, same as Terminal.app.

Default can stay off for existing users. A left/right Option split (iTerm-style) would be nice later, but a single toggle is enough.

Additional information

• App: ChatGPT / Codex desktop 26.810.52044 (com.openai.codex)
• OS: macOS 26.5.2 (25F84), Apple Silicon
• Related CLI issues (host terminal, not the app’s xterm): #3298, #4341, #9161
• Related app terminal customization: #25281

The desktop app source is not in this repo, and contributing.md says external PRs are not accepted, so this is a feature request rather than a patch.