In a Support discussion titled “Insert link of post does not generate preview,” MarcP reports that while topic links generate previews on their Discourse board, direct links to individual posts (e.g., https://meta.discourse.org/t/discourse-new-user-guide/96331/21) do not — unlike on Meta. MarcP suspects this is because the topic resides in a non-public category (minimum trust level 0). JimPas suggests adjusting the “post excerpt maxlength” setting under Settings > Posting to increase preview length, though notes it’s meant to be brief. MarcP clarifies the core issue: previews don’t generate for non-public categories (e.g., TL1-only), which michaeld explains is intentional to prevent leaking private content. MarcP proposes a compromise: show rich previews for authorized users and a polite “you don’t have permission” message for others — a feature request for future consideration.
Hi there all,
On my board when I link in a post to a topic, it will generate a nice preview like this:
It doesn’t do the same for direct links to posts/replies, like it does on Meta.
https://meta.discourse.org/t/discourse-new-user-guide/96331/21?u=marcp
Do I need to change something for this?
I think the issue here was that the topic was not in a public category (min. TL0). Is there a workaround to get nice links for topics in non-public categories?
The first link you show looks to be to the faq category, while the 2nd link is to an actual post within the category. If you wish to expand the amount of text shown in a summary of a linked post, in your Dashboard go to Settings/Posting and scroll down to post excerpt maxlength and change it from the default “300” to what you feel is necessary. But keep in mind this is supposed to be a brief “summary.” 
The point here is that these nice previews/summary don’t generate for non-public forums, for example if only TL1 can see the posts in that specific category. I guess that’s how it is, and should be.
@JimPas I meant, lol.
Have to run, but will respond when I get back. (Wife’s BD… going out for dinner )
That would open up a possibility to leak information out of such a non-public topic to the public.
I know. But maybe it’s possible for the team to look into an option to show a nice url for the users who are allowed to see the content, and for users who don’t have the correct rights maybe they can see a ‘nice’ you don’t have the rights to see this?