The system prompt context now mentions Fable 5 when describing available models: "The most recent Claude models are Fable 5 and the Claude 4.X family. Model IDs — Fable 5: '[id]', Opus 4.8: '[id]', Sonnet 4.6: '[id]', Haiku 4.5: '[id]'."
Evidence
Updated system prompt string (search for "The most recent Claude models are Fable 5")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
