Keywords for Root theme

Some times, we do write too many keywords or too long.

We could to show just the first 100-150 characters of the section.

We could to have a limitation with the number of keywords or also we could to write something like: Not more than 6 keywords are recomended. Or

These are added to your webbook cover page, and in your ebook metadata. Keywords are used by online book stores and search engines. Between 3 and 6 Keywords are recomended
(in good english)

In order to make to the writers to understand is not necesary and avoid such amound of words.