I have a demo AppClip which does Passkey registration and assertion in a wizard style page collection. Very often, the assertion would fail with the error "Couldn't communicate with a helper application". Retrying it few times will eventually work.
Full error:
Connection to agent service interrupted with error: Error Domain=NSCocoaErrorDomain Code=4097 "Couldn’t communicate with a helper application."
I don't know exactly what's causing this and how to prevent it? It only seems to happen during assertion, not registration.