LLM Failover in Python: Survive a Model Going Dark

On June 12, 2026 a US export-control directive forced Anthropic to pull Claude Fable 5 and Mythos 5 offline worldwide. Nine days later the endpoint still returns errors. Teams that had wired their product to that one model string woke up to a wall of failed requests and no switch to flip.

The lesson the whole developer community drew from it is blunt: a model can vanish overnight, and hard-coding a single provider is no longer acceptable engineering. Rate limits, regional outages, deprecations, and policy removals are all the same failure from your app's point of view — the call you depend on stops returning text.