Source Intelligence

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

All of v2.1.248 Home All releases olderv2.1.247 v2.1.250newer
Claude Code v2.1.248

Cloud sessions batch stream events and hold them back when nobody is watching

You'll notice
Useful1 Signal3
Cloud Sessions

Cloud sessions batch stream events and can hold them back when nobody is watching.

The no-subscriber hold is wired but its interval defaults to 0, so it does nothing.

Feature flag
tengu_ccr_no_subscriber_flush_ms 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 v2.1.248: not a boolean we can read

Read once, for one account on one subscription tier, against v2.1.248. It isn't a statement about your account. What a flag value here can and cannot tell you

What

The client that ships events for remote and cloud sessions gained a batch upload path and an awareness of whether anyone is subscribed to the stream. When the last server report said there were no subscribers, ephemeral stream events are buffered for the longer of the no-subscriber interval and the normal flush interval, and flushed immediately once a subscriber shows up. The extra delay comes from tengu_ccr_no_subscriber_flush_ms, default 0, which disables it.

Details
  • Single-event writes now go through the batch path.
  • Values are clamped to 0 through 60000; a non-finite value is logged and ignored.
  • Delivery reports of "received" mark subscribers as present, ending the delay early.
  • Consecutive thinking_tokens system events in the buffer are merged, summing their estimated token deltas.
Evidence

setNoSubscriberStreamEventFlushIntervalMs

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.248 →