What
When Claude Code sends a batch of events to the /worker/events address and the upload succeeds, it now always reads the server's reply if an onSubscribersReported callback is set. A callback is a piece of code that waits to be handed a result. The reply's has_subscribers value, which is a simple yes or no, is then passed to that callback.
Why
The client now learns after every upload whether the server reports any subscribers for these events. Nothing changes on screen.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The finding does not say what Claude Code does differently once it knows whether there are subscribers.