Opus 5.5 System Card Reveals METR's Undisclosed Info Source

Anthropic's Opus 5.5 system card reveals that safety evaluator METR relied on an undisclosed 'additional source' — an internal team with deep access to Anthropic's AI development data — whose conclusions the public cannot verify.

2026-09-23 ~ 2026-09-24 · 3 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
• METR says it used an undisclosed 'additional source' to understand Anthropic's AI R&D, buried in the Opus 5.5 system card — coherence · 2026-09-24