asyncio.run (Runner) replaces SIGINT with its own handler when the
current one is signal.default_int_handler: the first Ctrl+C silently
cancels the main task (invisible at the REPL prompt, leaving the task
marked cancelled) and the second raises KeyboardInterrupt, so a Ctrl+D
exit after a cancel was cancelled mid-memory.close() (SQLAlchemy
CancelledError traceback) and the CLI died with "Aborted!".
Install a distinct KeyboardInterrupt-raising handler before asyncio.run
so Runner leaves SIGINT alone, and have run_cancellable restore the
previous handler after each turn (remove_signal_handler leaves SIG_DFL,
which would kill the process on a stray Ctrl+C between turns).
asyncio signal handlers freeze ContextVars at install time; reinstalling
while allow_task_cancel was still False left cancel permanently disabled.
Use a process-level prompt depth counter and reinstall only after depth=0.
Max-rounds and destructive-tool prompts use asyncio.to_thread with
cancel paused on the main thread so multi-tool turns no longer look
like user cancel. Hooks may be sync or async.
NCBM