Пример robots.txt для MODx
User-agent: *
Disallow: /assets/cache/
Disallow: /assets/docs/
Disallow: /assets/export/
Disallow: /assets/import/
Disallow: /assets/modules/
Disallow: /assets/plugins/
Disallow: /assets/snippets/
Disallow: /install/
Disallow: /manager/Host: site.ru
Sitemap: http://site.ru/sitemap.xml