Claude Fable 5 feels good so far, but I don’t see it as a huge leap over GPT-5.5 or Opus 4.8 yet.
My biggest complaint: old AI research papers/blogs + basic questions often trigger an auto-downgrade to Opus 4.8.
Anthropic said last night there would be no more silent model switches (good), but please don’t nerf basic AI research or bio questions.