Hi sorry to bump an old thread but if I added the code suggested:

<?php
$doc = JFactory::getDocument();
$doc->addCustomTag('<meta name="robots" content="noindex" />');
?>

Would it stop all tags from being indexed?

I want only tags that have a menu attached to be indexed.

Thanks

The above code is correct.
You can check the menu item's id - stackoverflow.com/questions/19005478/joomla-3-1-get-active-menu-item-url - and print the snippet you found at will.

Hi Krikor

I don't understand what you mean.

Would that code stop all tags being indexed? even ones as a menu?

Basically I only want menus indexed and most of mine are made from K2 tags. But the rest of the tags I don't want indexed.

This code will tell the search engines not to include these pages.
It is up to the actual search engine to respect this code.
You can always block all bots, spiders etc and submit a sitemap of your own.

works