Claude Opus 5.5 release

Getting the most out of Opus 5.5 in Claude and Claude Code

Claude Opus 5.5 Intelligence, Performance and Price Analysis (Max)

Claude Opus 5.5

Big model release today - I wrote about Claude Opus 5.5, GPT-6 Sol, and GPT-6 Luna - plus comparison grids of pelicans by the different model families at different reasoning levels simonwillison.net/2026/Sep/22/...

Opus 5.5 was a good model in my early use tests, it is the first non-Fable/Astra model to feel like a Fable-class model, and much cheaper, but still hasn't fully solved the dense/weird language issue of the recent Claudes.