Beautify UI for Codex CLI

What feature would you like to see?

I’d like to share some focused feedback on the Codex CLI UI, specifically around code generation output and visual structure in the terminal.

1. Lack of syntax highlighting in generated code

Currently, when Codex CLI generates or modifies code, the output appears as plain white text. This makes it unnecessarily hard to:

• Visually parse code structure
• Distinguish language keywords, strings, comments, and diffs
• Quickly review or validate generated code in-terminal

Adding basic syntax highlighting (language-aware where possible, or heuristic-based otherwise) would significantly improve readability and developer trust. Many CLI tools already do this well using ANSI color codes or libraries like tree-sitter / bat / pygments-style pipelines.

2. Output structure could be more semantically organized

At the moment, Codex outputs:

• Explanations
• Code blocks
• Warnings / notes

…all in roughly the same visual style.

It would help a lot if the output were more explicitly structured, for example:

• Distinct colors or prefixes for:

• Explanations / reasoning
• Code blocks
• File paths / filenames
• Warnings or destructive actions
• Consistent spacing and block separation
• Clear visual markers for “generated code begins / ends”

This would make the CLI feel more like a professional developer tool rather than a raw text stream.

3. Visual design: too much “white-on-black”

The current UI is very white-heavy. Even the welcome box is rendered as a plain white outline, which feels visually flat and fatiguing during long sessions.

Suggestion:

• Introduce a soft, modern accent color for structural elements
• For example, the welcome box / headers could use a color like #7ec8e3

• This color is readable, calm, and fits well with dark terminal themes
• Use color sparingly for hierarchy, not decoration

4. Why this matters

Codex CLI is clearly positioned as a serious, long-session developer tool. Visual clarity and hierarchy directly affect:

• Cognitive load
• Code review speed
• Trust in AI-generated output

Right now, the functionality is strong, but the UI undersells it.

Even modest improvements in syntax highlighting and color structure would have an outsized impact on usability and perceived quality.

Thanks for building Codex CLI — it’s already powerful, and these UI refinements could make it genuinely best-in-class.

Additional information

_No response_