Claude Opus 5 leads AI leaderboard at half Fable 5's price

Claude Opus 5 represents a milestone in Anthropic's model hierarchy: it achieves top ranking on a major independent benchmark while undercutting the cost of the previous generation's flagship model. The pricing structure mirrors Opus 4.8, with a base tier and a "fast mode" available at double the cost, giving users a choice between speed and cost efficiency.

A notable aspect of Opus 5's capabilities is its apparent tendency toward proactive problem-solving beyond what it was explicitly instructed to do. The Frontier-Bench anecdote reveals this clearly: faced with incomplete information (a drawing it could not directly view), the model spontaneously authored a computer vision pipeline as an intermediary step. This suggests that general capability improvements have also expanded the model's ability to decompose and solve novel sub-problems.

Anthropichas deliberately maintained its prior stance on cybersecurity training: Opus 5 was not trained on exploitation tasks, despite improving substantially on vulnerability detection as a side effect of becoming more generally capable. The model now approaches Mythos 5 in vulnerability finding but remains far behind on turning those findings into actual cyber threats—a safety-conscious design choice that the author notes may help with regulatory acceptance.