Meh, the option to trigger "silent downgrades" seems to be gone, they will now get exposed as real downgrades, apparently.
See here ->
fry69
Update: Anthropic came to their senses and walked back their policy of dumbing down Fable 5 and hiding this behavior.
-> simonwillison.net/2026/Jun/11/...
h/t @simonwillison.net