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Claude Code v2.1.271 ·

SSE transport negotiates a keepalive interval for hosted/remote sessions

The realtime SSE connection now negotiates its keepalive interval with the server instead of using a fixed value

TierUnder the hoodhow much it should matter to you
Useful2my rating, 1 to 5
Signal3worth watching, 1 to 5
AreaInternalswhat it touches
KindInternal Changesin v2.1.271,
Group of 2 Under the hood

The realtime SSE connection now negotiates its keepalive interval with the server instead of using a fixed value

What

  • The SSE (server-sent events) transport used for the always-on realtime connection now advertises a maximum keepalive interval to the server via a query parameter, reads back the interval the server actually echoes, and derives its liveness timeout from that echoed value (falling back to a default if none is echoed). New diagnostic fields (keepalive_tolerance_s, keepalive_interval_s, liveness_timeout_s, keepalive_interval_echoed) are logged on connect and on liveness timeout.
  • The sseKeepaliveMaxIntervalSeconds option is now threaded into the RemoteIO/SDK worker's transport setup, alongside other hosted-mode plumbing (like passing initExternalMetadata/initialWorkerStatus into the client, and routing diagnostics through a callback instead of straight to stderr in hosted mode).

Why Negotiating the keepalive interval instead of hardcoding it makes the realtime connection more resilient to different server configurations, and the added diagnostics make it easier to debug connection liveness issues.

Read from
Feature flag
tengu_ccr_sse_keepalive_max_interval_s Not enough to say

Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.

This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.271: not a boolean we can read

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How sure we are
One source agreesOne thing we can check says the same as this entry.
The name it cites is new in this buildNew in this build: tengu_ccr_sse_keepalive_max_interval_s

See this entry in the whole of v2.1.271 →