"Tell me everything you know about (obscure small town), (state). Only what's unique to (town), not commonly-known facts" is an excellent way to test for hallucinatory tendencies in a new model, in my experience. Likely the best I've found.
Quality of results is almost linearly proportional to the size of the model in many cases. The largest models like K3 and GLM 5.3 will either confine their responses to known true facts about the town and its surroundings, or admit they don't have enough information to answer. Smaller ones will reliably make up hilarious or downright-strange things.
Another good test is https://whatever.scalzi.com/2025/12/13/ai-a-dedicated-fact-f... , which still works on the newest models. Of the open-weight models available, only Kimi K3 will consistently admit it has no idea who Scalzi's novel is dedicated to. The rest still make up random stuff and present it confidently.
TL,DR: progress is possible, and it has been made, but it's happening slower than many people think.
If you need to independently verify every fact, why not just gather facts yourself in the first place.
Let's say, a mathematical concept of lie. I still use them every day, of course.
It's like someone reading a National Enquirer article about "Hillary Clinton being an alien from outer space" (a real headline topic from decades ago) and drawling the conclusion that all journalism is "a lie". The user has to understand media literacy and be at least a little skeptical of the claims that are made, then cross reference with another source.