What is a codex-theme-v1 string?

It is the shareable theme payload used by the Codex desktop app. It includes the App theme colors, fonts, semantic colors, variant, and a base code-theme ID in one copyable string.

Why is the Import button disabled?

Check the codex-theme-v1 prefix, JSON syntax, six-digit hex colors, and codeThemeId. Also confirm the string's variant matches the row you pasted it into — Appearance has separate Light theme and Dark theme rows, and a variant mismatch leaves the Import button disabled even when the rest of the string is valid. Some app versions have also been reported to accept only code-theme IDs already available in their dropdown.

Can I use the same theme in the Codex App and CLI?

Not directly. The desktop App uses a codex-theme-v1 JSON string, while Codex CLI uses a TextMate .tmTheme file. You need a version of the theme in each format.

Guide

How to import and change a Codex theme

Codex App and Codex CLI use different theme formats. Choose your surface below, follow three steps, and apply a new look in a couple of minutes.

Updated Jul 18, 2026 · 2 min read

Codex App themes vs. CLI themes

The two formats solve related problems, but they are not interchangeable.

Codex App

Desktop interface theme

Format: codex-theme-v1 JSON string

Changes interface colors, fonts, semantic colors, and code palette.

Path: Settings → Appearance → Light/Dark theme row → Import

Codex CLI

Terminal syntax theme

Format: TextMate .tmTheme file

Changes terminal syntax highlighting and diff colors.

Path: $CODEX_HOME/themes → /theme

Choose where you use Codex

Select your Codex surface, get the right theme format, and follow its installation steps.

The desktop app imports a complete codex-theme-v1 string from Appearance settings. Appearance has separate Light theme and Dark theme rows, each with its own Import button — copy a ready-made theme first, then follow these three steps.

Before you begin: copy a theme

Pick a ready-made Codex App theme and copy its complete import string.

View all themes

Open Settings

Open the app menu and choose Settings, or press Cmd+, on Mac.

Choose Appearance

Open Appearance, then find the Light theme or Dark theme row that matches your string's variant.

Paste and import

Paste the full string into that row's Import dialog, import it, and check a code diff.

Example: Nord theme for Codex App

codex-theme-v1:{"codeThemeId":"one","theme":{"accent":"#88c0d0","contrast":100,"fonts":{"code":null,"ui":null},"ink":"#d8dee9","opaqueWindows":true,"semanticColors":{"diffAdded":"#a3be8c","diffRemoved":"#bf616a","skill":"#b48ead"},"surface":"#2e3440"},"variant":"dark"}

Import button disabled?

Confirm that the value starts with codex-theme-v1:, contains valid JSON, uses six-digit hex colors, and does not include Markdown code fences. Also check that the string's variant matches the row you pasted it into — a "variant":"dark" string left the Import button disabled in the Light theme row, and only turned it active once pasted into the Dark theme row instead. Some app versions also accept only a codeThemeId already listed in their code-theme dropdown.