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DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

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Claude Code v2.1.220

Auto-mode classifier requests now send a new beta header

Under the hood
Useful2 Signal0
Permissions

Auto mode's permission classifier now tags its requests with a beta marker on Anthropic-hosted sessions.

CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS
What

The permission classifier used by auto mode attaches a beta descriptor to its API requests, where the previous build sent none. Both classifier stages now carry it.

Details
  • Registers WA("auto_mode_classifier", "auto-mode-classifier-2026-07-16") and adds it to the frozen known-betas list, so it is also reachable through the header lookup map.
  • In 2.1.219 the classifier's request builder was a stub that unconditionally returned an empty extraBetas array; it now returns this beta.
  • Gated on provider being "firstParty" and the base URL being api.anthropic.com. Suppressed by CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS or hipaa mode, in which case the list stays empty.
Evidence

auto-mode-classifier-2026-07-16

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Related

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

See this entry in the whole of v2.1.220 →