Pydantic AI v2.64.0 Adds Sticky Model Fallback for Conversation Continuity
Photo: Forkast
The release of Pydantic AI v2.64.0 on October 30, 2026, introduces an opt-in sticky setting for ModelFallback, as detailed in the official release notes and the associated pull request #11330 . This feature allows a conversation to remain on a fallback model that has successfully answered a request, rather than defaulting back to the primary model at the start of every subsequent request step. By enabling sticky=True, builders can alter the default model selection logic to respect the recent failure history of a specific conversation.
Source: Forkast
