How to set up no-castling FEN

So, this is the result of an experiment where I tried to have a standard placement, but not able to castle, daily tournament. The first attempt failed, but another has worked.

Only v3 lets you start a tournament from FEN (Forsyth-Edwards Notation). There was a more limited pre-set list of thematic openings in v2.

This is the FEN for the standard position with normal castling:

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

The part which indicates that both black and white are still allowed to castle either K-side or Q-side is the "KQkq". When I set up a tournament using that string of notation, but with that part cut out, it was like this:

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w - 0 1

The chessdotcom server assumed that the missing part had just been forgotten, and inserted it itself in the tournament parameters. Games ended up being completely standard with castling possible:

https://www.chess.com/tournament/no-castling-to-castle-is-not-allowed

The next time, I used 2 dashes, like this:

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w - - 0 1

Those characters acted as "delimiters" to indicate that the space between them actually should be empty, and so this time the tournament worked as intended:

https://www.chess.com/tournament/no-castling-trying-again

This is just the result that I got specifically on chessdotcom's daily tournament setup. Other sites may not work the same  way, and I don't know whether or not there are rules or guidelines to this FEN feature which should apply in all cases.