Buried in the Opus 5.5 system card: METR used an undisclosed 'additional source of information'
burny_tech · x · 2026-09-23
A curious line buried in Anthropic's Opus 5.5 system card is drawing attention: METR, the organization evaluating dangerous AI capabilities, states it made use of "an additional source of information which we are not able to disclose at this time" to understand AI research and development at Anthropic.
The wording hints METR had some undisclosed channel into Anthropic's internal R&D process, prompting speculation about what that access involves and how it shapes their evaluations. The system card is linked in the original post.
Related event: Opus 5.5 System Card Reveals METR's Undisclosed Info Source(3 posts)→
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