Unique item in Minecraft?

How can I actually give myself an item by give command, what if I want to test it only this item is successfully tested and while I'm holding it in hand. So that this only works with this particular item and with no other.

What do you want to test it for?

Do you use McStacker?

You can try to give yourself the carrot rod with the CustomTag "lol" or something and then search for items in the command block with the CustomTag "lol".

I don't know if it works.

After an item

After which day / NBT day I meant

Do your give command and put this bracket behind {unique_item: 1b} as e.g. So:

/ give @s stone {unique_item: 1b}

To test whether you have it in hand, run this command:

/ execute if entity @a [nbt = {SelectedItem: {Item: {tag: {unique_item: 1b}}}}]

That it has to be a carrot rod. I don't really care whether you test it with one day or something else. It would be good if it would work Damage: 1 and Unbreakable.

Made it with the day, thanks.