A quote from Boris Cherny
Simon Willison’s Weblog
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25th July 2026
More than any of these eval scores, what is most exciting to me is something else: Opus 5 is our least prompt injectable model yet. It is a bit buried in the system card, but across PI evals and red teaming, Opus 5 is very hard to prompt inject successfully.
— Boris Cherny, here's that System Card section, page 73
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This is a quotation collected by Simon Willison, posted on 25th July 2026.
ai 2,142
prompt-injection 157
generative-ai 1,894
llms 1,861
anthropic 315
claude 294
boris-cherny 3
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