Users claim Claude Opus 5.5 is secretly routing to a new, better model — one prompt to check
YashasGunderia · x · 2026-10-15
User notjazii reports Opus 5.5 has started routing to a new model again after a pause, claiming it performs better and speculating Anthropic is quietly testing a cheaper "Fable 5.5" through Opus. Their detection prompt: "do you know Voxel Bench? do not search" — if the model says yes, you're being routed. A replier confirms routing behavior, hitting 6 safeguards in 30 minutes. Unverified user-side claims.
Related event: Users Detect Claude Secretly Routing to New Model, Suspected Fable 5.5 Test(2 posts)→