What should smart glasses do when a request fails?
They should show the stage that failed and give the wearer a clear next action. A disconnected phone, unavailable service and completed request are different states. An old answer should never quietly stand in for a new one.
Keep the response tied to the request
Our design recommendation is to give each request an identifier and discard responses that no longer belong to the active interaction. That avoids a common asynchronous problem: the first request finishes after the second and replaces the newer result. A retry should create an understandable state change instead of leaving the wearer wondering whether anything happened.
Imagine asking for your next meeting, then changing to directions. If the calendar request finishes late, it should not replace the route. A small indication that the calendar request was canceled or superseded is enough; the wearer should not have to diagnose the network to understand the screen.