Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
ElsewhereArea: what it touches
Internal ChangesKind: in v2.1.296,
Internal ChangesSection of the release
Unclear Which headers the new source actually adds is not stated.
What
When Claude Code sets up the connection it uses to talk to the API, it now waits for a separate source to supply extra headers before finishing. Headers are small labelled pieces of information sent along with each request. Before, all headers were put together at once, without waiting on anything.
The extra headers depend on which part of Claude Code is sending the request and on the current permission settings, meaning the rules about what Claude is allowed to do. They are merged into the headers for every kind of connection Claude Code makes:
a connection through a gateway (a server that sits between Claude Code and the API)
a connection that does not sign in with OAuth (the browser-based login)
the default connection
The base set of headers that goes with every request is now also set explicitly.
Why
This can change which headers your requests carry. That matters if you add your own headers with ANTHROPIC_CUSTOM_HEADERS, or if a proxy or gateway in your setup inspects incoming headers.
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 doubtWhich headers the new source actually adds is not stated.
Anthropic's release notes agreeFixed $.http.fetch in mods refusing a HEAD request when the response declares a Content-Length over the 4 MiB body limit
