Use when designing, building, reviewing, testing, or improving how a terminal program interacts with people - command and subcommand naming, arguments, flags, defaults, prompts and confirmations, help and usage text, error messages and exit codes, stdout vs stderr, piping and structured/JSON output, color and styling, progress indicators and spinners, quiet/verbose/debug/json modes, TTY detection, interactive vs non-interactive/CI behavior, config and environment precedence, shell-completion UX, accessibility, and i18n.
