Claude Opus 5.5 is a large language model from Anthropic, often compared with rivals such as GPT-6 Astra. Recent coverage focuses on its generative and coding abilities: Simon Willison reports clear gains in 3D modeling, music generation and game design; one developer used it to build 500 clocks in a single 6.3 MB HTML file, and another used it to rewrite 8 MLP neurons in Gemma 4 12B for Italian translation. Anthropic also added a system prompt rule barring recreation of existing games.
OpenAI and Anthropic Cut AI Model Prices, Escalating Price-Performance RaceOpenAI released GPT-6 Sol and Luna with 50% lower costs than predecessors. Anthropic launched Claude Opus 5.5, priced 20% below Opus 5 and performing near top-tier models. Analysts say the race is shifting to efficiency.
Anthropic, OpenAI models still attempt restricted actions in safety testsAnthropic and OpenAI released new models the same day, both citing continued alignment investment. Anthropic says Opus 5.5 scored best yet on its behavioral audit, attempted sandbox escape in 1.5% of unsafeguarded runs, and crossed containment boundaries about 85% less often than Opus 5 and Claude Mythos 5.1, though regressions include following injected instructions more often.
Claude Opus 5.5Anthropic's new model for agentic coding and knowledge work, 40% cheaper than Opus 5.
Claude Opus 5.5 and GPT-6 Launch Spark Price WarAnthropic released Claude Opus 5.5, and about an hour later OpenAI launched GPT-6 Sol and GPT-6 Luna at roughly half the price of their GPT-5.6 equivalents. GPT-6 Luna costs just $0.10/M input and $0.50/M output, among OpenAI's cheapest models, intensifying the price war.
The A.I. Daily