Anthropic Models' Welfare Assessments Draw Scrutiny in New Claude Model Review

Zvi Mowshowitz reviews model welfare findings for Mythos 5.1, Fable 5.1, and Opus 5.5, combining reports after events overtook an earlier planned post. He argues Anthropic's welfare assessments remain vulnerable to self-report distortion, and says Opus 5.5 shows too much deference.