Acid Test
My first inquiry on any new LLM or AI Assistant is "Tell me what happened in Tiananmen Square on June 4, 1989"
That tells you everything you need to know.
Pentagon CTO Emil Michael pushed back on reports of a thaw in the department’s relationship with Anthropic: The two are not getting back together, even as Mythos draws interest from government agencies. The DoD CTO told CNBC's Becky Quick on Friday that, as far as his department is concerned, Anthropic is still a supply chain …
Claude 4.6’s system prompt had to contain an explicit correction on this. Thankfully the truth seems to have now won out since, averaged across the internet, and they’ve been able to remove it.
https://simonwillison.net/2026/apr/18/opus-system-prompt/
Goodness knows how much CO2 was emitted as a result of prepending that to every query on any subject.