Overuse of rule of three, cliches like "This was not X. It was Y." and similar, obligatory bulleted list, overall overly grandiose. None of these are a smoking gun, but the smell is definitely here. AI detection tools also confirm my suspicions. I don't have a horse in the race in regards to the content, since I'm not a Ruby developer, I would just prefer to not see AI-written comments on HN. If this is so important, you can take the time to type it out yourself.