Claude Fable 5.1 & GPT-6 Astra packages are live

hydration

Frontend

Hydration correctness — why server and client HTML must match, the values that reliably break it, and how to handle genuinely client-only content.

Choose your model

Available for 11 model families. The engineering substance is the same in each; the structure, checklist phrasing and constraint ordering are tuned per family.