Under the hood
Control-protocol requests now fail fast if already cancelled before being sent
What
The internal control-request mechanism used by the Claude Code SDK now checks upfront whether the request's cancellation signal is already triggered. If so, it immediately rejects with a "Control request aborted" error instead of sending the request and only reacting to cancellation afterward.
Why
This avoids sending requests that are already known to be cancelled, saving wasted work and making cancellation behave more predictably.