Auto set light/dark theme variants based on OS preference

[galah92]

What variant of Codex are you using?

v0.105.0

What feature would you like to see?

In continuation to #1618, I would like the Codex CLI to auto detect the MacOS preference (light/dark) and apply the relevant theme accordingly.

Additional information

No response

[etraut-openai]

You're using the CLI, right? Terminal programs generally have their own light/dark settings and color themes that are independent of the OS's.

[galah92]

CLI, yes. And in bat for example I can do:

--theme="auto"
--theme-light="minimal-light"
--theme-dark="minimal-dark"

Also many programs like neovim, ghostty, support that and auto switching when I toggle that option at the OS level.

Edit: This might be helpful.

[davidgilbertson]

After update to 105 I see this, is that the intended default? I'm on Windows Terminal with dark mode.

It seems that the /theme options all change text colour, but because the background colours are close to medium lightness, neither light nor dark text gives particularly good contrast. Changing to the GitHub theme makes diffs just readable, but it's a real squint-fest, and other text becomes unreadable.

This makes 105 unusable for me, unless there's some option for "make it like it used to be"?

[davidgilbertson]

If I do this:

$env:COLORTERM="truecolor"
codex

Then Codex correctly recognises my terminal as truecolor and I get the default dark green/red and can read diffs.

For fellow Terminal users, this can be set as a regular environment variable, or in the settings JSON, as a property of a particular profile in Terminal:

...
"guid": "{574e775e-4f2a-5b96-ac1e-a2962a402436}",
"name": "PowerShell",
"environment": {
  "COLORTERM": "truecolor"
}
...

The underlying issue is that the supports-color crate used to detect color seems to just check environment variables, maybe some other heuristics, not the actual capability. E.g. if I run node then process.stdout.getColorDepth() it returns returns 24 for my terminal, which should be treated as truecolor.

[laffo16]

These background colours are blinding me, please can we do something to get those more natural colours we had in 0.104 or someway of easily configuring these background colours in the diff (including none as an option). I would of much preferred if 0.104 was the default theme after upgrading to 0.105. Completely onboard with everything david has mentioned above.

update:
david's fix with base16-256 theme is ok (i can see again!)

[davidgilbertson]

I think a quick fix in Codex would be logic like: "if a terminal can't do true color, don't use background colors".
Then a more refined step would be to better detect truecolor-able terminals.

[galah92]

@etraut-openai not sure why this issue was closed with a fix PR - the original request was to support light/dark variants based on OS preference.

[etraut-openai]

Sorry, Github automatically closed it because it was referenced in the PR commit notes. Reopening.