Role-playing Games Stack Exchange is a question and answer site for gamemasters and players of tabletop, paper-and-pencil role-playing games. It only takes a minute to sign up.
Sign up to join this community
The Samurai fighter subclass (Xanathar's Guide to Everything, p. 31) has the level 7 feature Elegant Courtier, part of which states:
Whenever you make a Charisma (Persuasion) check, you gain a bonus to the check equal to your Wisdom modifier.
However, my samurai only has 7 Wisdom (a -2 modifier). There is also no "minimum +1" or "unless it's negative" qualifier specified for this ability. Does this mean he actually gets worse at Persuasion checks once he hits level 7?
This is a great example of an ability score not being helpful based on your build. Unfortunately, you've got all the logic right in your question and without the qualifiers, you add whatever your modifier is (even if it's negative.) In a build optimized for the Samurai, the WIS modifier would be a Bonus. In your case, it's negative modifier, turning that bonus into a penalty.
In your case, I'd probably not try to Persuade people much :)
Player's Handbook makes a distinction between "a bonus" and "a penalty":
A class feature, a spell, a particular circumstance, or some other effect might give a bonus or penalty to the check
"Bonus" is a positive modifier:
His attack bonus is his Strength modifier (+3) plus his proficiency bonus (+2), for a total of +5.
"Penalty" is a negative modifier:
The target takes a -4 penalty to all attack rolls
When a modifier is meant to be positive or negative, the PH doesn't say you "gain a bonus", or "add bonus", it just says you "add modifier". Here's an example where always positive modifier is called "bonus", while a potential negative one is called simply "modifier" (emphasis mine):
When you make an attack with a weapon, you roll a d20 and add your proficiency bonus (but only if you are proficient with the weapon) and the appropriate ability modifier.
The Elegant Courtier explicitly says you get a bonus:
you gain a bonus to the check equal to your Wisdom modifier
If your WIS modifier is negative, it can't be a bonus. This complies with the narrative part:
your discipline and attention to detail allow you to excel in social situations
The other answers take a rules-as-written approach to your question (which is probably what you're looking for), but I think that the following answer is very much in the spirit of 5e, and worth considering:
Ask your DM
As a DM myself, if a player asked, I would allow them to simply ignore the rule (not apply their negative modifier). I really doubt it would create a balance problem. Ask your DM.
