Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
ModelsArea: what it touches
Internal ChangesKind: in v2.1.277,
Internal ChangesSection of the release
What
Claude Code now has a helper that decides which model ID counts as the 'canonical' representative for each of the Opus, Sonnet, and Haiku model families: an ID qualifies if it starts with claude- and either matches the family's base name exactly, or matches the base name plus a date, or the base name plus @date. When building the map of canonical IDs per family, this canonical form is now preferred over any other ID seen for that family. The code that builds the model list also now loops over a shared list of the three family names instead of writing them out separately each time.
Why
This makes model selection more consistent when multiple IDs for the same model family exist (for example, dated snapshot versions), ensuring the same canonical ID is chosen rather than an arbitrary one.