$_PARAM not automatically 'seen'

I need to filter database queries based on the url param.

If I understand this… (taken from here)

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Then this should work:

1. Route is /login:school
   

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2. In server action I set up $_PARAM.school (1)
3. I set it in a vallue with output on so I can see if it’s getting the value. (2)
   

I’m expecting to see the query parameter here but it’s empty:

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