Claude Opus 5 Is Highly Capable, But Is No Mythos

Anthropic released Claude Opus 5, a more affordable AI model designed to match the performance of its predecessor Fable 5 on many tasks but without Mythos-level capabilities. Opus 5 excels at local reasoning and as a subagent but struggles with complex global tasks and requires guidance to follow instructions effectively. User reception is mixed, with some disliking its conversational style and negativity.