[FEATURE] Feature request: Support NO_COLOR environment variable to disable ANSI color output

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Claude Code does not respect the https://no-color.org/ environment variable, which is a widely adopted convention for disabling ANSI color output in terminal applications.

Setting NO_COLOR=1 (or any non-empty value) in the environment has no effect on Claude Code's color output.

Proposed Solution

Claude Code should honor NO_COLOR as specified by https://no-color.org/ — when set to any non-empty value, suppress all ANSI color escape codes in output.

Alternative Solutions

The current workaround is to set syntaxHighlightingDisabled: true in ~/.claude/settings.json, but even when this is set, claude renders colors for some reason. At least let me customize the theme like most applications do, or provide a monochrome theme.

Priority

Whatever you consider

Feature Category

CLI commands and flags

Use Case Example

• Some terminal emulators don't render colors correctly.
• Some people can't easily read code when syntax highlighting is enabled.

Additional Context

_No response_