Thank you…rather than use the lengthy list made by others I throughly read the first two DiD stories. Those are the basic rules.
"The Portals were discovered already in situ." It was accidental. Cassandra did not build them.
"There is more than One Hero and Hero Caretaker in operation at all times."
"The rules for the Portals were already in place when discovered. Experimentation was necessary to find out what those rules were/are."
Then I figured that others have restricted or expanded the rules to suit the plot so I could do the same with mine.
Ceiling is the 'replicator.' It's been in use for 1000 years. Get's lonely being smart enough to replicate personal tastes of a thousand years of use…why not be smart enough to ask if it tastes right? There are stories where the receiver of the food needs to improve the taste to match expectations. Lengthy explanations are surely stored in memory…and the replicator must be able to recognize each hero because the replicator gets it right.
Same goes for the Healing Chamber…smart enough to clear out epidemic illnesses. Smart enough to recognize a thousand years of planetary poisons. Smart enough to heal problems the Hero didn't know existed. Smart enough to communicate? Several Heroes and Damsels problems were 'displayed' for the Caretaker to read them off the display. Earth computers are smart enough to read text and translate it into talk.
Metal doesn't pass the Portal. The staff isn't metal. Perhaps the watch isn't metal either.
The rings aren't Cassandra made. "A Sapphire of a certain size." A stone on a chain worn around the neck or carried in a box in a pocket works too. The portal passed the ring…the portal passes the chain. All metal…even rivets, zippers and belt buckles don't pass…but the ring findings do. the sapphire chain does.
If anyone is 'Pure of heart' the Powers that Be are. Attempting to save the earth from self-inflicted folly is a heroic mission.