Reddit crossposts hide details in the poster's profile post

A subreddit post can have almost empty selftext (e.g. just "^^") and a url pointing to the original at /r/u_<user>/comments/<id>/, or to /gallery/<id> for an image post. Details such as building, price and terms live only there, so follow url and fetch that id too. Also pull the author's submitted.json, because reposts can reveal different terms, price drops or a separate listing. In this session, skipping this step led a subagent to merge two different rooms from one poster into one wrong listing; the user caught it.