Hi all, first post here. I'm currently trying to make a homebrew magic item. It is a hat that gives a +2 bonus to Constitution saving throws, as well as Constitution ability checks. The saving throw portion seems to be working fine, but no matter what I do, the +2 bonus for Constitution ability checks never applies to any character wielding the item. Is there a reason why the ability check bonus wouldn't be reflected on rolls by the character?  The item in question is linked below as well.

https://www.dndbeyond.com/homebrew/creations/magic-items/3432780-sunset-hat/edit

There are no skills associated with Constitution. When DDB programmed it they programmed it to reflect the bonuses to Ability checks under the Skills section. I assume you were expecting it to appear on the Ability itself, but that reflects your raw ability score and the modifier it provides. If it reflected there it would mess up everything else that draws from those numbers, like HP for instance.

Since there is no skill to reflect the bonus, you cannot see it. Add a custom skill to the character sheet and name it “Constitution Checks.” Designate Con as the associated ability and list it as Not Proficient. Thatt should reflect that bonus as long as DDB didn’t skip Con in the programming since they didn’t need it.

Just thought I'd mention, while you can use a custom skill like this to note fixed-value bonuses to an ability check, it won't work for noting Advantage/Disadvantage. Which is a bummer.

Edit after further testing: However, if you customize an existing skill to use a different ability, then the advantage/disadvantage will show up!

Unfortunately, I tried a Luckstone, which is supposed to give +1 to ability checks and saving throws, and that doesn't seem to apply to custom skills either. Sorry, Sposta.

But as I thought I mentioned in an edit to my post (which got removed somehow?) you can customize an existing skill that you never use, and do a Skill Stat Override to CON, and that will apply modifiers that give a bonus or advantage to Constitution checks.

Oh well, it may not add the bonus automatically (like I said, they didn’t need it to do that; so they might just not have bothered) but they still don’t have to give up an existing skill display, a Custom Skill is one other way to go. Like I said, it may not automatically add the bonus, but setting various bonuses, & degrees of proficiency are all available for custom skills. (I use them for Tools all the time, even drop excerpts from Xanathar’s for quick reference, like suggested DCs and skill interactions.) And I know that Con (Athletics) is a Commonly enough used houserule that if it weren’t possible you and I would have been answering that along with all the other stuff we end uprepeating every week. 🤷‍♂️

I see, so using the Custom Skills is more or less bypassing anything to do with modifiers from items and such, you just have to add Magic/Misc bonuses to account for that sort of thing. But you still don't get to indicate Advantage/Disadvantage.

I usually use “[Name] (A)” / “[Name] (D)” or something along those lines.