Vercel's AI Gateway lets developers specify which model should answer if Anthropic's Fable 5.1 refuses a request. Its release note describes an ordered fallback list: the gateway tries Fable first, then proceeds through the configured alternatives until one succeeds.
The example uses Opus 5 followed by Sonnet 5. Vercel presents this for cases where safety classifiers also reject routine coding or debugging requests. The resulting application has a defined recovery path, but a successful response may come from a different model than the application's first choice.
