Just because it’s circulating social media, it doesn’t mean it’s not a spoiler. If you’re reposting reddit content without even looking at Reddit, it would make sense to build respecting spoilers and NSFW markers into the bot. Dunno how your bot operates, but Reddit does provide that information through its API. Since Lemmy does not support spoiler tags, it would be preferable to have a separate preview image link, because marking post as NSFW is not foolproof, as users can disable blur for NSFW posts in the account settings, and NSFW doesn’t indicate that the content is a spoiler. It rather suggests that it’s some +18 content.