{"version":"2.1.227","anchor":"tool-search-beta-header-falls-back-when-experimental-betas-a","canonical_anchor":"tool-search-beta-header-falls-back-when-experimental-betas-a","heading":"Tool-search beta header falls back when experimental betas are turned off","tier":"notice","area":"Tool Search","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.227\/e\/tool-search-beta-header-falls-back-when-experimental-betas-a","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.227","markdown":"### Tool-search beta header falls back when experimental betas are turned off\n\nTurning off experimental betas now falls back to the older tool-search beta header everywhere.\n\n**What**\n\nSessions 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.\n\n**Details**\n\n- Triggered by the `CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS` environment variable or by HIPAA compliance mode.\n- Provider-based selection of the older header is unchanged.\n\n**Evidence**\n\n`advanced-tool-use-2025-11-20`\n\n- Area: Tool Search\n- Tier: You'll notice\n- Useful: 2\/5\n- Signal: 3\/5"}