Tedi
Should just work.

When will the mod be updated to 1.18.15 or 1.19? OmegaHaxors

Neitronus
Any object can be given sharpness but right now the whetstone is hard coded to only allow sharpening of pickaxes (for dig speed) knives (for skinning speed) and falx (for attack damage) Yes this means you can apply sharpness to any item you can carry in your inventory, even ones where it makes no sense to have it (such as berries or a stick)

If you want to be able to sharpen a mod tool you should either create your own whetstone capable of doing so, or patching the existing one to be compatible.
How it works internally is basically the mod checks the item in your hand and if you're holding an itemstack with a sharpness attribute, if you have it gives you bonuses to the three stats then deducts one point of sharpness for each 'use' of the tool. It's -1 sharpness for each stone dug, -1 sharpness for each attack done, and -1 sharpness for each carcass skinned. Obviously this process will not happen if the sharpness is 0 because if it went below that you would start having to deal with imaginary numbers, and those don't produce anything of value. Another little fun fact is that these three stats are possible because of the preexisting class attributes, as the sharpness system plugs into those to give you the bonuses. That's why you can't sharpen shovels: the mine speed increase only increases the speed of breaking stone blocks as it was intended for use with the blackguard.

Does this work with modded items or they should include sharpness field in their definition first in order for whetstone to be able to access it via ingame interaction?

Zeorik
Yeah it's something I wanted but isn't something I know how to do.
Due to the nonlinear nature of sharpness you should notice when your tool is dull, at least.
It will maintain its edge for most of the time but then suddenly start dropping off hard.

There's also always the debug menu which shows you all attributes, including sharpness.

The only complaint/ request I could make is a tooltip addition perhaps? So that you can tell how 'sharp' any givewn tool is, instead of guesswork.

Omega, you've been on a grind lately. Good you're adding these awesome and useful things to the game via mods.

Yes, that's good too. So great what you are doing for us. You can think of a lot of things. I wish you success .

znatik I was actually going to make that effect stronger but I heard they were going to buff tiered knives so I kept it to 2x.

Oh, how cool the atoms are tired of sawing the carcasses of animals for half an hour. Very useful mod. Thank you.

Thanks NESHK0
I'll put it in the next update

ru.json 

{
"whetstone:block-whetstone": "Точильный камень",
"blockdesc-whetstone": "Позволяет затачивать ваши инструменты за счет прочности (максимум 100 раз). Инструмент теряет 1 значение заточки после каждого использования. Бонус (в %) к скорости инструмента равен корню (Очки заточки) * 10. <br><br> Не все инструменты могут быть заточены, а так же, если прочность ниже текущего значения заточки."
}