{"version":"2.1.267","anchor":"anthropic-betas-values-now-filtered-through-a-new-exclusion","canonical_anchor":"anthropic-betas-values-now-filtered-through-a-new-exclusion","heading":"ANTHROPIC_BETAS values now filtered through a new exclusion list before being applied","tier":"internal","area":"Elsewhere","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.267\/e\/anthropic-betas-values-now-filtered-through-a-new-exclusion","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.267","markdown":"### ANTHROPIC_BETAS values now filtered through a new exclusion list before being applied\n\nANTHROPIC_BETAS entries are now filtered against a new exclusion list before being applied\n\n**Unclear.** The finding doesn't say which beta names are on the new exclusion list or why they're excluded.\n\n**What**\n\nWhen Claude Code builds its list of beta headers from the `ANTHROPIC_BETAS` environment variable (used to opt into experimental Anthropic API features), each entry is now also checked against a new exclusion list. Entries that match are dropped, on top of the existing trimming of blank entries.\n\n**Why**\n\nSome beta names can now be blocked outright from being applied via `ANTHROPIC_BETAS`, regardless of what the user sets, beyond the earlier org-compliance-based blocking of the whole variable.\n\n- Area: Elsewhere\n- Names: `ANTHROPIC_BETAS`\n- Tier: Under the hood\n- Useful: 1\/5\n- Signal: 2\/5"}