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Sweep 22 Oct 2026 · 21:04Z Build v2.1.309 528 read Stable v2.1.308 Latest v2.1.309 Next v2.1.309 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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Claude Code v2.1.299 ·

SSE connection can be opened through a pluggable stream opener

The SSE transport accepts an optional streamOpener to open its stream and tells the server about it in the connect URL

Group of 2 Under the hood Internal Changes
JSON All of v2.1.299
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2Signal: worth watching, 1 to 5
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Internal ChangesKind: in v2.1.299,
Internal ChangesSection of the release

What

SSE (server-sent events) is a way for a server to keep sending updates over one open connection, and Claude Code uses it for remote sessions. Before, the transport always opened that connection itself with a direct fetch inside connect().

  • The SSE transport now takes an optional streamOpener. When it is set, the stream is opened through it. It receives the url, headers, signal and an openSse fallback.
  • A query parameter on the connect URL now lists capabilities, and includes one when a streamOpener is set. Before, the query parameter was used only for the worker-attestation policy.
  • connect() is split into connect() and openStream(e).

No code inside Claude Code that supplies a streamOpener was found.

Why

This lets a program hosting Claude Code route the remote connection through its own transport and let the server know it is doing so. Ordinary use is unchanged unless something supplies an opener.

See this entry in the whole of v2.1.299 →

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