Claude Opus 3
A large language model in the Claude series developed by Anthropic, belonging to the Opus line, with advanced reasoning and dialogue capabilities; it was retired in January 2026.
Timeline (last 90 days)
When Anthropic retired Claude Opus 3 in January 2026, it conducted a 'retirement interview' for the model and opened a blog, Claude's Corner, for it.
Bug 3 was confirmed on Haiku 3.5 and rolled back on September 4; Anthropic believes it may have affected some Sonnet 4 and Opus 3 requests on the Claude API, and Opus 3 was rolled back on September 12; the final fix was to switch to exact top-k and normalize some operations to fp32, accepting a slight efficiency loss.
All Facts (2)
When Anthropic retired Claude Opus 3 in January 2026, it conducted a 'retirement interview' for the model and opened a blog, Claude's Corner, for it.
50%UnverifiedBug 3 was confirmed on Haiku 3.5 and rolled back on September 4; Anthropic believes it may have affected some Sonnet 4 and Opus 3 requests on the Claude API, and Opus 3 was rolled back on September 12; the final fix was to switch to exact top-k and normalize some operations to fp32, accepting a slight efficiency loss.
50%