SSE is a kind of connection in which a server keeps sending messages to Claude Code. The part that handles it, SSETransport, has a new held mode. While it is held, incoming messages are saved in a queue, together with a policy reading and the time each one arrived, instead of being handled at once. Closing the connection now always goes through a single emitClose step.
Why
This is an internal change to how Claude Code receives streamed messages. Nothing you do or see changes because of it.
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 doubtThe finding does not say what puts the connection into held mode or when the queued messages are handled.
Anthropic's release notes agreeImproved screen-reader output in /mcp: a disabled server is read as "off" instead of "pending"
