How to just connect a switch to a sensor so the switch state matches the sensor?

I just want to connect a switch and a window sensor so that the switch state reflects the window sensor. I've successfully created a conditional rule like:

IF
sensor CLOSED
THEN
switch ON
ELSE
switch OFF
ENDIF

but with all of the conditions and options, even this is rather complex to set up for something so basic. Is there a simpler way I've missed?

Not really. That's a fairly simple rule, and it's probably the easiest built-in way to do it now (but keep an eye out for something I mentioned in your other thread on this subject).

Also note that triggers are an important part of a rule, so it's a good idea to share the whole rule and not just its actions. Yours needs to be "changed" for this to work.

How about Simple Automation?

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