Unicode, Color, Accessibility, and Non-TUI Fallbacks

Use this skill when terminal output must be visually correct, readable, inclusive, and robust across fonts, locales, themes, and assistive technologies.

Text correctness rules

• Display width is not byte length, code point count, or user-perceived character count.
• Cursor movement and deletion should operate on grapheme clusters.
• Layout should measure printable text after stripping ANSI control sequences.
• Double-width characters, combining marks, emoji sequences, variation selectors, and zero-width joiners must be tested.
• Treat ambiguous East Asian width as narrow by default unless the target environment explicitly differs.

Visual design rules

• Use semantic roles: error, warning, success, info, muted, selected, focused, disabled.
• Do not encode meaning by color alone; pair color with text, shape, icon, or position.
• Provide ASCII fallback for box drawing, braille charts, block elements, emoji, and private-use icons.
• Avoid assuming Nerd Fonts or patched fonts.
• Support light and dark backgrounds, 16-color, 256-color, truecolor, and no-color modes.

Color preferences

Respect user and environment preferences:

• NO_COLOR disables non-essential color.
• CLICOLOR, CLICOLOR_FORCE, and FORCE_COLOR may force color depending on ecosystem conventions.
• TERM=dumb, non-TTY output, and CI usually imply plain output unless overridden.
• Provide explicit flags such as --color=auto|always|never, --plain, and --ascii.

Accessibility requirements

• All functionality must be keyboard-operable.
• Focus indicators must be visible without relying on color alone.
• Avoid flashing more than three times per second.
• Allow spinner, animation, and live-region suppression for reduced motion, logs, and CI.
• Provide screen-reader friendly alternatives: plain prompts, line-oriented commands, --json, --plain, or documented stdin/stdout workflows.
• Use meaningful labels, stable ordering, and visible status messages.

Failure modes

Reference files

• references/text-measurement.md - Unicode width, graphemes, emoji, BiDi, and ANSI measurement.
• references/accessibility-fallbacks.md - Color policy, screen-reader alternatives, and inclusive UX checklist.