The Sonnet 4.5 model migration now intelligently skips execution for Bedrock and Vertex AI users, preserving their platform-specific model configurations.
What changed:
- Migration checks if you're using Bedrock (
CLAUDE_CODE_USE_BEDROCK) or Vertex AI (CLAUDE_CODE_USE_VERTEX) - Third-party platform users skip the migration entirely, keeping their existing model settings
- Only Anthropic API (firstParty) users have their model preferences reset
Why it matters: Bedrock and Vertex have different model catalogs and naming conventions. This prevents the migration from breaking configurations on those platforms.
Evidence
v4Q() at line 443591 with platform check via k8() at line 351873
Strings lifted out of the shipped bundle, so the claim above can be checked against them.