Can someone let me know how to disable page description for simple users, but let the know to post topics and reply to them?
Topic on Extension talk:StructuredDiscussions
It seems like Flow almost not providing any hooks, so I guess there is no way to extend its logic without code modifications.
But look here https://www.mediawiki.org/wiki/Talk:MediaWiki There is a lock sign at page description and only administrator is allowed to edit it
The whole page is protected, not only the description. And Vedmaka is right: there is no way to protect the description only, except by changing the code itself. A task exists for that feature.