Quoting Boris Cherny

# A quote from Boris Cherny Source: [https://simonwillison.net/2026/Jul/25/boris-cherny/](https://simonwillison.net/2026/Jul/25/boris-cherny/) 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](https://twitter.com/bcherny/status/2080713091688583312),here's that[System Card section](https://www-cdn.anthropic.com/c5fbac3f0b1280a933ebd26d3cb8bb9f5bdeaf48/Claude%20Opus%205%20System%20Card.pdf#page=73), page 73 Posted[25th July 2026](https://simonwillison.net/2026/Jul/25/)at 12:42 am ## Recent articles - [OpenAI’s accidental cyberattack against Hugging Face is science fiction that happened](https://simonwillison.net/2026/Jul/22/openai-cyberattack/)\- 22nd July 2026 - [A Fireside Chat with Cat and Thariq from the Claude Code team](https://simonwillison.net/2026/Jul/21/cat-and-thariq/)\- 21st July 2026 - [Kimi K3, and what we can still learn from the pelican benchmark](https://simonwillison.net/2026/Jul/16/kimi-k3/)\- 16th July 2026 This is a**quotation**collected by Simon Willison, posted on[25th July 2026](https://simonwillison.net/2026/Jul/25/)\. [ai2,142](https://simonwillison.net/tags/ai/)[prompt\-injection157](https://simonwillison.net/tags/prompt-injection/)[generative\-ai1,894](https://simonwillison.net/tags/generative-ai/)[llms1,861](https://simonwillison.net/tags/llms/)[anthropic315](https://simonwillison.net/tags/anthropic/)[claude294](https://simonwillison.net/tags/claude/)[boris\-cherny3](https://simonwillison.net/tags/boris-cherny/)