Wikimedia Bugzilla is closed!

When editing a page, I'd like the ability to somehow provide a one sentence
summary of a page. This could be a new kind of tag or a keyword, or even a
separate edit box. Note, I'm not talking about the edit comments; I mean a
summary of the content of the page itself.

I'd like to be able to access this summary in the following ways:

1) It should probably be used as the value of a meta name="description" tag for
the page.
2) There should be some way to get to it with extensions (as a part of a SQL
query, for example).
3) (Optional) There could be a way to append the description after a link.

What I'm interested in doing with my wiki is creating an extension that can
build automatic bullet lists of page links based on categories, where after each
link is a summary of what the page is. I can already get the page of links,
thanks to the DynamicPageList2 extension. I could hack this extension to include
the page summaries, if they existed; however, at present, there does not seem to
be any way to even create such summaries, much less access them.