Curiously can't find much about this online. As a divination wizard, is there any reason you couldn't use a high portent roll to guarantee success on the Arcana check to copy a spell from a scroll into your spellbook?
Just for reference this is the basis for my theory saying that is fair using RAW. As always, check with your DM to make sure!
Portent: "When you finish a long rest, roll two d20s and record the numbers rolled. You can replace any attack roll, saving throw, or ability check made by you or a creature that you can see with one of these foretelling rolls. You must choose to do so before the roll, and you can replace a roll in this way only once per turn."
Copying spells from scrolls/spellbooks: "When a spell is copied from a spell scroll, the copier must succeed on an Intelligence (Arcana) check with a DC equal to 10 + the spell's level. If the check succeeds, the spell is successfully copied."
It appears to me like its fairly clear, portent can replace an ability check and that would include the ability check (Arcana) related to copying a spell scroll into your spellbook!
Copying spells from scrolls/spellbooks: "When a spell is copied from a spell scroll, the copier must succeed on an Intelligence (Arcana) check with a DC equal to 10 + the spell's level. If the check succeeds, the spell is successfully copied."
That's a weirdly hidden rule. You'd think it would be mentioned in the section on "Your spellbook" in the wizard class, rather than just in the description of a spell scroll.
The thing to also keep in mind is that only copying a spell from a spell scroll require an ability check, copying one from another source doesn't unless noted otherwise. It follow the rules for when Learning Spells of 1st Level and Higher instead;
Copying a Spell into the Book. When you find a wizard spell of 1st level or higher, you can add it to your spellbook if it is of a spell level you can prepare and if you can spare the time to decipher and copy it.
Copying that spell into your spellbook involves reproducing the basic form of the spell, then deciphering the unique system of notation used by the wizard who wrote it. You must practice the spell until you understand the sounds or gestures required, then transcribe it into your spellbook using your own notation.
For each level of the spell, the process takes 2 hours and costs 50 gp. The cost represents material components you expend as you experiment with the spell to master it, as well as the fine inks you need to record it. Once you have spent this time and money, you can prepare the spell just like your other spells.
The thing to also keep in mind is that only copying a spell from a spell scroll require an ability check, copying one from another source doesn't unless noted otherwise. It follow the rules for when Learning Spells of 1st Level and Higher instead;
Copying a Spell into the Book. When you find a wizard spell of 1st level or higher, you can add it to your spellbook if it is of a spell level you can prepare and if you can spare the time to decipher and copy it.
Copying that spell into your spellbook involves reproducing the basic form of the spell, then deciphering the unique system of notation used by the wizard who wrote it. You must practice the spell until you understand the sounds or gestures required, then transcribe it into your spellbook using your own notation.
For each level of the spell, the process takes 2 hours and costs 50 gp. The cost represents material components you expend as you experiment with the spell to master it, as well as the fine inks you need to record it. Once you have spent this time and money, you can prepare the spell just like your other spells.
One thing to keep in mind is that when copying spells from a spellbook or other source it has to be "of a spell level you can prepare".
You can't copy spells to your spellbook unless you can prepare them already.
Copying from a scroll has the added constraint of the ability check:
"A wizard spell on a spell scroll can be copied just as spells in spellbooks can be copied. When a spell is copied from a spell scroll, the copier must succeed on an Intelligence (Arcana) check with a DC equal to 10 + the spell's level. If the check succeeds, the spell is successfully copied. Whether the check succeeds or fails, the spell scroll is destroyed."
In this case, the requirement that the spell is of a level you can prepare is also a pre-requisite for copying to the wizard's spellbook.
Curiously can't find much about this online. As a divination wizard, is there any reason you couldn't use a high portent roll to guarantee success on the Arcana check to copy a spell from a scroll into your spellbook?
Yes Portent allow you to replace any ability check you make such as Intelligence (Arcana) check.
Just for reference this is the basis for my theory saying that is fair using RAW. As always, check with your DM to make sure!
Portent: "When you finish a long rest, roll two d20s and record the numbers rolled. You can replace any attack roll, saving throw, or ability check made by you or a creature that you can see with one of these foretelling rolls. You must choose to do so before the roll, and you can replace a roll in this way only once per turn."
Copying spells from scrolls/spellbooks: "When a spell is copied from a spell scroll, the copier must succeed on an Intelligence (Arcana) check with a DC equal to 10 + the spell's level. If the check succeeds, the spell is successfully copied."
It appears to me like its fairly clear, portent can replace an ability check and that would include the ability check (Arcana) related to copying a spell scroll into your spellbook!
That's a weirdly hidden rule. You'd think it would be mentioned in the section on "Your spellbook" in the wizard class, rather than just in the description of a spell scroll.
The thing to also keep in mind is that only copying a spell from a spell scroll require an ability check, copying one from another source doesn't unless noted otherwise. It follow the rules for when Learning Spells of 1st Level and Higher instead;
Yes, portent would work in this situation.
"Not all those who wander are lost"
One thing to keep in mind is that when copying spells from a spellbook or other source it has to be "of a spell level you can prepare".
You can't copy spells to your spellbook unless you can prepare them already.
Copying from a scroll has the added constraint of the ability check:
"A wizard spell on a spell scroll can be copied just as spells in spellbooks can be copied. When a spell is copied from a spell scroll, the copier must succeed on an Intelligence (Arcana) check with a DC equal to 10 + the spell's level. If the check succeeds, the spell is successfully copied. Whether the check succeeds or fails, the spell scroll is destroyed."
In this case, the requirement that the spell is of a level you can prepare is also a pre-requisite for copying to the wizard's spellbook.