[Dead Eddie]

You'll likely want to use hook vbcms_article_save_start

I did the following proof of concept (yeah, I hate the code):

PHP Code:

if(empty($_POST['description']))
{
     $_REQUEST['description'] = "hello world!";
} 


If you want to use the first few lines of the article, you'll have to do some text processing to get the markup out of it first. It's certainly doable, just not something I'm in the mood to look at.

Oh, and this'll only works on future articles, not current ones.