Opus 5.5 System Card Reveals METR's Private Access to Anthropic Data

Anthropic's Opus 5.5 system card reveals that METR used an undisclosed information source, with an internal team given deep access to Anthropic's AI R&D data—leaving the public unable to verify the evaluation.

2026-09-23 ~ 2026-09-23 · 2 related posts

• Claude system card reveals METR's internal-access team shared conclusions, not evidence — rohanpaul_ai · 2026-09-23
• Buried in the Opus 5.5 system card: METR used an undisclosed 'additional source of information' — burny_tech · 2026-09-23