What
Sessions that disable experimental betas now send the older tool-search-tool-2025-10-19 beta header instead of advanced-tool-use-2025-11-20. Previously the older header was used only on Vertex, Bedrock, Mantle and gateway providers.
Details
- Triggered by the
CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETASenvironment variable or by HIPAA compliance mode. - Provider-based selection of the older header is unchanged.
Evidence
advanced-tool-use-2025-11-20
Strings lifted out of the shipped bundle, so the claim above can be checked against them.