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Sweep 02 Oct 2026 · 18:55Z Build v2.1.288 509 read Stable v2.1.285 Latest v2.1.287 Next v2.1.288 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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Claude Code v2.1.287 ·

Claude Code recognizes rejected beta headers by the API's error text

Claude Code now spots a rejected beta header from the API's own error wording rather than from the header name alone

Under the hood Internal Changes
JSON All of v2.1.287
Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
APIArea: what it touches
Internal ChangesKind: in v2.1.287,
Internal ChangesSection of the release
What

Claude Code sometimes sends an anthropic-beta header, a request label that asks the API for preview features. When the API refuses one, Claude Code now spots this from the error text:

  • The error says there is an unexpected value for the anthropic-beta header.
  • The error contains beta_header: followed by the header's name.

It no longer treats an error as a rejection just because it mentions the header name. An error that mentions both evict_on_complete and beta is still treated as a rejection.

Why

This affects how Claude Code falls back when the server rejects a beta header.

How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtIt is not clear what Claude Code does differently once it detects a rejection.

See this entry in the whole of v2.1.287 →

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