[pescetom]

There is some symmetry here
with my previous post, in that I am unfamiliar with inverted minors and guessing a bit. But my 3♣ and GiB's 3♥ both seemed reasonable and coherent with the explanations. Now 3♠ was explained as some preposterous number of spades rather than an ask, so I punted 3NT which did not look unlikely anyway.
WTF (as might say an eminent contributor, now for hire) is 4♥ about?

[a_user]

Your 3NT bid was a little exuberant and now your partner is cueing its way to slam.
After all, if its got 15+ HCP and you've got 15+ HCP, it must be time to break out the Prosecco and invert the bottle over your minors.

[steve2005]

Well the mistake is the explanation of 3♣ is wrong.
Surely 3♣ is passable so it should be 11-13 hcp not 11-21
and 3♥ is essentially game forcing, unless you think you can somehow stop in 4♣
So 3♥ should be showing 14 or 15+ hcp not 10+

3NT should not be showing 15+ hcp it merely shows the 11 you have promised plus stopper in the black suits

[Huibertus]

steve2005, on 2025-December-01, 20:13, said:

Well the mistake is the explanation of 3♣ is wrong.
Surely 3♣ is passable so it should be 11-13 hcp not 11-21
and 3♥ is essentially game forcing, unless you think you can somehow stop in 4♣
So 3♥ should be showing 14 or 15+ hcp not 10+

3NT should not be showing 15+ hcp it merely shows the 11 you have promised plus stopper in the black suits

The actual bidding shows the problem is NOT the explanation of 3NT. If the explanation was wrong and the agreement was right, there would be a pass on 3NT. The actual explanation and sub sequent auction also shows the actuall agreement on 3 ♣ is it can contain more than a minimum, which, yes, is stupid.

The agreements cause North to investigate slam, expecting more from south.

As stupid as these agreements are, it's not unreasonable of North to act upon it, trusting partner.

[pescetom]

 Huibertus, on 2025-December-02, 04:58, said:

The actual bidding shows the problem is NOT the explanation of 3NT. If the explanation was wrong and the agreement was right, there would be a pass on 3NT. The actual explanation and sub sequent auction also shows the actuall agreement on 3 ♣ is it can contain more than a minimum, which, yes, is stupid.

The agreements cause North to investigate slam, expecting more from south.

As stupid as these agreements are, it's not unreasonable of North to act upon it, trusting partner.

Even if the agreement is that 3♣ can contain much more than a minimum (which is illogical, given that it has to be non-forcing and compatible with a minimum), North has no apparent reason to assume it is not a minimum, nor a hand that could be interested in slam opposite a minimum.
After the 3♥ game force showing a stopper (which is quite logical, agreed), at least one of 3♠ and 3NT has to promise no more than a minimum and willingness to stop in 3NT. If it was 3♠ then it was grossly misexplained.