● Covered by 1 source · 1 reportMedium impact1 neutral
Claude Opus 5.5 Released, Offering Improved Performance and Reduced Cost
Key points
- Claude Opus 5.5 released, first in 5.5 family.
- Performs like Claude Fable 5.1, costs 40% less than Opus 5.
- Improved performance in complex tasks, including code migration.
- Achieves best scores on automated behavioral audit for safety.
Introduction of Claude Opus 5.5
Claude Opus 5.5 has been introduced as the initial model within the new Claude 5.5 family. This release marks the first model since the company's call for pacing the frontier of AI development. External evaluators, including Frontier Design and METR, tested the model prior to its public release.
Performance Enhancements
Opus 5.5 shows a performance increase over Opus 5, becoming the new leading model. Early testers reported significant performance gains on complex tasks; one tester completed a 680,000-line code migration in under a day. The model also demonstrated effectiveness in identifying and correcting software inefficiencies, succeeding in 39 out of 40 attempts to reduce web app load times without altering behavior, compared to Opus 5's smaller improvements that sometimes affected app behavior. Another test showed Opus 5.5 scoring higher than other Claude models in graphics and polish when building a game from a single prompt.
Safety and Alignment
Opus 5.5 achieved the highest scores to date on the automated behavioral audit, an alignment test suite that simulates thousands of scenarios. The model is less prone to irreversible actions and acting outside defined boundaries, and it exhibits increased resistance to prompt injection compared to Opus 5. Alignment testing has been expanded to include longer and impossible tasks, as well as scenarios based on real incidents. The full evaluation details are available in the Opus 5.5 System Card.
Cost Efficiency and Access
Opus 5.5 requires less computational power than Opus 5, which is reflected in its pricing. The model's performance is comparable to Claude Mythos 5.1 in biology and cybersecurity, leading to similar safeguards. Vetted organizations can apply to the Life Sciences Verification Program to use Opus 5.5 for biology research. Access to the Cyber Verification Program for verified cybersecurity practitioners will also be expanded in the coming weeks.
✨ This summary was generated by AI from the outlets' reporting listed below. It is not independently verified and may contain errors — check the original sources. How BrevFeed works →
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Reporting from
Claude Opus 5.5, the first model in the Claude 5.5 family, has been released, performing at the level of Claude Fable 5.1 on most tasks while costing 40% less than Opus 5. This new model demonstrates significant performance improvements in complex tasks like code migration and software optimization, alongside enhanced safety features.