Anthropic releases Opus 5.5 with lower prices and Fable-level performance

Anthropic’s newest model, Opus 5.5, was released, setting a new state-of-the-art in coding and knowledge work performance. Opus is the most capable and expensive tier in Anthropic’s three-tier Claude lineup. Notably, the release outpaces the larger Fable model in many benchmarks and succeeded in informal tasks that Fable failed to complete. The new model is significantly cheaper than its predecessor, charging $20 per million tokens for outputs compared to $25 previously, alongside faster execution and lower compute requirements. Communication changes make Opus 5.5 less likely to use jargon and more likely to put important information at the start of its messages. The launch follows Opus 5 released on July 24, with Sonnet 5.5 and Haiku 5.5 slated for release in the coming weeks. Anthropic states that Opus 5.5 is comparable to Mythos in biology and cybersecurity capabilities, subjecting it to the same safety safeguards that limit its use in discovering exploits or developing biological weapons. This marks the first release since CEO Dario Amodei embraced calls to pace capability advancements to match alignment progress.