Comment by ed-is-ai

The big issue I have with Fable is this. From the Anthropic email announcing Fable 5.1. So basically they're giving us a Ferrari, which will point blank refuse to do certain stuff - forcing us to go out in our Mustang. Their choice, not ours

"Safeguards and automatic fallbacks (beta): Fable 5.1’s biology and cybersecurity classifiers block fewer benign requests and now permit vulnerability finding in source code. Blocked requests return an error and are not charged to you. On the Messages API, opt in to fall back to another model so users get a response instead of an error. We recommend Opus 5 for biology and Opus 4.8 for cybersecurity. In Managed Agents, fallback is built in."