We had discussed that a bit on slack. A neat way would also be to make the flags return an enum.IntFlags. The class of which might fit into np.dtypes (better repr and reduces the spam in the module)

Another way to solve this without exposing the flags in python would be to add a member hanging off the dtype object that indicates if it's supposed to be pickled for serialization (that internally would do the check against the flags).

It is pretty niche, but the property hanging off the dtype object is also pretty easy to implement - just add a new function that does the flag check and add an entry for it in the arraydescr_getsets array in numpy/_core/src/multiarray/descriptor.c.

Exposing all the flags to python would also work, and I guess we already expose the flags too so exposing the whole enum probably makes sense, just wanted to comment that the property is also not very hard to add.

Yes, a proprety is fine, I would like to not spoil the properties too much with things users will never really need, but overall it is not a big issue.