The error message could be more specific about the issue. Consider clarifying that stdin is a TTY (interactive terminal) and therefore cannot be used for piped input.

[synthable]

The error message could be more specific about the issue. Consider clarifying that stdin is a TTY (interactive terminal) and therefore cannot be used for piped input.

        progress.fail('No persona file specified and stdin is a TTY (interactive terminal); piped input is required');
        console.error(
          formatError({
            command: 'build',
            context: 'input validation',
            issue: 'no persona file specified and stdin is a TTY (interactive terminal); piped input is required',
            suggestion:
              'use --persona <file> to specify a persona file or pipe YAML content to stdin (e.g., cat file.persona.yml | ums build)',

Originally posted by @Copilot in #48 (comment)