Anthropic releases Claude Opus 5.5 and OpenAI counters with two cheaper GPT-6 models

Anthropic introduced Claude Opus 5.5 and reduced its price by 20%, whereas OpenAI announced two new GPT-6 models, Sol and Luna, priced at half the cost of their predecessors. Opus 5.5 cost $4 per million tokens and $20 for output, resulting in a 40% decrease in cost compared to Opus 5. Cache reads dropped by 60%, to $0.20, and faster serving mode was priced at $8 for input and $40 for output.

OpenAI halved the price of both new models, with Sol at $2 per million input tokens and $10 per million output, and Luna at $0.10 and $0.50. Anthropic claimed Opus 5.5 matched its Fable 5.1 model on most tasks, and the new model showed 40% faster output generation and 40% higher task completion in AutomationBench. On scientific research, Opus 5.5 scored 58.7% compared to Opus 5's 29%, and on GDPval-AA v2.1, it achieved 1846 Elo points, 46 points ahead of Opus 5.

Both models are accessible through various platforms, with Opus 5.5 also available as claude-opus-5-5 on the Claude Developer Platform and through AWS, Google Cloud, and Azure.