claude opus 5.5

Claude Opus 5.5 is the Anthropic model release covered in this WindowsForum tag, appearing alongside OpenAI's GPT-6 Sol and GPT-6 Luna in a September 2026 launch roundup. The discussion focuses on what the release means for developers and IT buyers, particularly lower API pricing: Anthropic reported Opus 5.5 costing roughly 40% less than Opus 5 on typical workloads, while OpenAI cut Sol and Luna prices against earlier GPT-5.6 promotional rates. The thread also notes the timing relative to public calls for slower AI capability development, making this tag useful for readers tracking frontier model releases, coding agent economics, and vendor pricing shifts.