tengu_ccr_sse_keepalive_max_interval_s
A Claude Code feature flag, read out of the shipped bundle. It has been in the build since v2.1.271, including the newest one read.
Realtime SSE connection now negotiates its keepalive timing with the server instead of using a fixed value
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.271.
In the changelogs
4Releases whose published page names tengu_ccr_sse_keepalive_max_interval_s.
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v2.1.296
Remote sessions drop oversized event messages, and the preview tunnel tracks unanswered pings
Hosted remote sessions now drop event messages with too many fields, and the preview tunnel can reconnect after a run of missed pings
gate cited by this entry
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v2.1.290
Remote sessions can now turn away apps on devices that fall below a trust policy
Remote sessions now check attached apps against a device trust policy and refuse ones that fall below it
gate cited by this entry
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v2.1.271
SSE transport gains a negotiated keepalive interval
Realtime SSE connection now negotiates its keepalive timing with the server instead of using a fixed value
gate cited by this entry, found in this entry's text
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v2.1.271
RemoteIO worker gains hosted-mode diagnostics and metadata plumbing
The RemoteIO worker gains hosted-mode diagnostics, extra startup metadata, and a keepalive setting
gate cited by this entry
Gate readings
3| Release | Resolved | This account | Anonymous | Compiled default |
|---|---|---|---|---|
| v2.1.296 read on another version | Not enough to say | no value returned | no value returned | not a boolean we can read |
| v2.1.290 read on another version | Not enough to say | no value returned | no value returned | not a boolean we can read |
| v2.1.271 read on another version | Not enough to say | no value returned | no value returned | not a boolean we can read |
Two arms, because they disagree: this account is the one account this site reads and anonymous is a baseline with no identity attached. A reading says nothing about your account, and off cannot rule out a rollout both readings sit outside of. What these readings can and cannot show.
First cited
2The earliest release whose published evidence quoted tengu_ccr_sse_keepalive_max_interval_s was v2.1.271, 14 Sep 2026. That is the oldest release this project wrote about it, so it is a floor on the name's age and not the release that introduced it. It is not a presence reading: which builds carried the name is the table below.
Presence across releases
1Build by build
35One row per release since the first build this name was read out of. Absent means the build was read and the name was not in it, never mined means no bundle for that release was ever archived, and a declared type or a default is only ever what that release's own bundle stated.
Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the feature flag does. All feature flags.