You'll noticeTier: how much it should matter to you
3Useful: my rating, 1 to 5
4Signal: worth watching, 1 to 5
ModelsArea: what it touches
ImprovementsKind: in v2.1.310,
What probably matters to youSection of the release
What
When you use Claude Code through Google Vertex or Amazon Bedrock, it checks which default model it can use for each model tier. Before, the fallbacks came only from a list built into Claude Code. Now:
Each tier can take its target model from a published model document.
A model that is too old is treated as unavailable when it was a document default.
A model your administrator has mapped through modelOverrides counts as an accepted fallback.
Claude Code can check document defaults again and record any that turned out not to work.
