[Bug] Alt+T(option+T) not enabling thinking mode on macOS

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Found 3 possible duplicate issues:

1. https://github.com/anthropics/claude-code/issues/14284
2. https://github.com/anthropics/claude-code/issues/13854
3. https://github.com/anthropics/claude-code/issues/14322

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If you're on iTerm, go to the iTerm preferences -> Profiles -> Keys -> set the Left/Right Option key to Esc+.

Same for me on Kitty.

Setting the macos_option_as_alt option to yes in kitty.conf did the trick.

https://sw.kovidgoyal.net/kitty/conf/#opt-kitty.macos_option_as_alt

Setting the macos_option_as_alt option to yes in kitty.conf did the trick.

Unfortunately that particular fix makes it so you can't use macOS diacritic input. Using alt as a mod key for a macOS terminal app is generally undesirable behavior, so IMO the default should be changed to something else.

> Setting the macos_option_as_alt option to yes in kitty.conf did the trick. Unfortunately that particular fix makes it so you can't use macOS diacritic input. Using alt as a mod key for a macOS terminal app is generally undesirable behavior, so IMO the default should be changed to something else.

Correct, there are some consequences to this setting, well explained in the link. Proceed with caution. Just in case anyone really wanted to work around it. I guess it'd be cool to be able to customize the shortcut, if not possible already.

On macOS, the Option key types special characters by default (Option+T = †). Terminals need to be configured to send Option as Meta/Escape for Alt shortcuts to work.

We've added a fix in the upcoming release - you'll see a notification guiding you to run /terminal-setup.

How to fix

| Terminal | Setting |
|----------|---------|
| Terminal.app | Run /terminal-setup in Claude Code, or: Settings → Profiles → Keyboard → ✓ "Use Option as Meta key" |
| iTerm2 | Settings → Profiles → Keys → General → Left Option Key → Esc+ |
| VS Code / Cursor / Windsurf | Add "terminal.integrated.macOptionIsMeta": true to settings.json |
| Ghostty | Add macos-option-as-alt = true to config |
| Kitty | Add macos_option_as_alt yes to kitty.conf |

Note: This disables special character input (é, ñ, ü) via Option. Use /config to toggle thinking if you need both.

Great, no international keyboard support anymore (no not everyone in the world is using US keyboard layout...) on MacOS if you want to quickly toggle thinking mode.

@bogini I'm completely lost on what to expect even if I toggle thinking mode in config, because previously this would have a hint (blue color) in the prompt box indicating thinking is on. Now there's no visual cue when it's on or off.

Right now, with this issue, I need to use the ultrathink keyword in all prompts

Adding "terminal.integrated.macOptionIsMeta": true, to my VS Code settings.json worked for me!

in Zed

```setting.json
{
"terminal": {
"option_as_meta": true
}
}

Adding "terminal.integrated.macOptionIsMeta": true, to my VS Code settings.json worked for me!

can not use opt+l for @ symbol then.

For lost souls using Ghostty - I'll hint that this also works - in ~/.config/ghostty/config

macos-option-as-alt = right

I have opt+t as a designated shortcut to spawn terminal with skhd, being able to change the shortcut back to Tab would be great.

I don't really understand this change, the tab for switching thinking mode was super intuitive. Now we're stuck with a clunky shortcut requiring two steps to enable or disable.

This is a massive regression in UX. Please reverse requiring such special configurations to enable core features.

Requiring a Terminal setting change to break international natural language inputs and to make a feature work is a poor choice.

The power of Claude Code is to build by using one's own natural language. This makes software development accessible to many more people. Thinking Mode is an essential feature but with the change to opt+t it removes the accessibility of Claude Code once gained.

opt+t doesn't work for me as it's bound to a global keyboard shortcut.

Please add back the option to use Tab!!!

I dont have a "meta" key - so I can't use thinking mode anymore.

please return this keymapping reworking to something more universally standard.

mapping option (alt) to "meta" in iterm would impact all other uses of the alt key - so its not a fix.

you can't have your cake and eat it too - there are only so many key combinations, not everything should have key combos - OR you should make it user configurable.

This is an insane UX choice. Up there with removing the images from the text input.

Right now I can't use thinking mode LOL

anthropic doing anthropic things... what a BULL*HIT @ThariqS revert this or fix it for fucks sake!

Pure greed!

My current "workaround" => curl -fsSL https://claude.ai/install.sh | bash -s 2.0.65 and "DISABLE_AUTOUPDATER": 1 in ~/.claude/settings.json.

The changelog says this change is included in 2.0.72, but I had to revert as far back as 2.0.65.

Same problem here. Why in the .... you will select something like "Meta+t", when that shortcut is widely used by thousand other apps. And when a simple tab was working....

what the fuck did the dev smoke when the make this decision? thats the worst shit I have seen in months from claude.. Imagine just setting a combination for thinking mode international users cant even use and now I have to some sketchy shit in config files to change your shit? what the fuck man

and im talking about standard windows mode with a german keyboard layout

@Alexander96f although the issue is unpleasant, keep your tone appropriate to the situation. It is resolved anyways since the thinking is applied automatically. Ultrathink also does not work anymore.
Anger never helps.

@xu-chris agree on the tone, but this is not actually resolved. Any Option-* hotkey is affected with standard ABC extended layout, like Model selector Opt+P.

@Alexander96f although the issue is unpleasant, keep your tone appropriate to the situation. It is resolved anyways since the thinking is applied automatically. Ultrathink also does not work anymore. Anger never helps.

Well sorry for my tone. Was just really pissed because I spend like 30 minutes to try to figure out how to use the thinking modus. So there is no option any longer to manually switch into thinking modus like think think hard or ultrathink??? Either way its horrible comunicated or I am just too stupid to find any proper actuall informations on this.

Still unresolved on Ghostty. macos-option-as-alt = true set and confirmed, Option+T still outputs †. See #32087 for the broader Ghostty compatibility issue.

If you're on iTerm, go to the iTerm preferences -> Profiles -> Keys -> set the Left/Right Option key to Esc+.

Doesn't work for me. What am I missing? Any Mac + iTerm2 user who has figured it out?

This is a macOS-specific issue: Option+T produces the † character instead of sending Alt+T to Claude Code.
Fix — remap Option key behavior in your terminal:
iTerm2:

1. Go to Preferences → Profiles → Keys → General
2. Set "Left Option key" to Esc+ (instead of "Normal")
3. This makes Option+T send \eT (Escape + T) which Claude Code interprets as Alt+T

Terminal.app:

1. Go to Preferences → Profiles → Keyboard
2. Check "Use Option as Meta key"

Alacritty (alacritty.toml):

[keyboard]
bindings = [
  { key = "T", mods = "Alt", chars = "\^[t" }
]

Ghostty:

macos-option-as-alt = true

Why this happens: macOS treats Option as a character modifier by default (producing special characters like †, ∑, ƒ). Most TUI applications expect Option to act as the Meta/Alt key, sending escape sequences. The terminal needs to be configured to change this behavior.
This affects all Alt-based shortcuts in Claude Code, not just Alt+T.

except that it used to work, and then it stopped. @yurukusa - this was a _regression_ - not something that never worked. changing the terminal only for one product is just bad software practice.

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