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
Recent articles
- One-shotting a Raccoon Heist game using Claude Fable 5 - 5th August 2026
- New release of LLM adds support for reasoning traces, OpenAI Responses, server-side tools, and smarter logging - 4th August 2026
- Stateless MCP has recaptured my interest (and inspired mcp-explorer and datasette-mcp) - 31st July 2026