Thread:Extension talk:TextExtracts/Including text in nutshell box

I run a wiki that uses a summary message box on some articles. (Wikipedia, by contrast, doesn't use such a template on articles.) I want to include the contents of the box following "in a nutshell:" as the first thing in the  that Extension:TwitterCards adds. (TwitterCards builds the Open Graph description from the result of TextExtracts.) However,  by default causes all   and   elements to be ignored. What would be the least-bad way to format a summary message box in such a way that  will not cause its text to be removed?