Don't sell in-context learning short. Right now I'm waiting on Claude to wrap up the latest of a half-dozen extensive changes to XML files for a fairly-obscure (and obsolete) closed-source electronics CAD program. I am pretty sure it doesn't know anything about these files besides what's in the XML .DTD file (which I also gave it.)

This is a very novel, reasonably-poorly-documented problem, and so far it has batted 1.000.