Bast L. wrote:
Since trip is an attack action (page 243), the check is an attack roll. Since it's a trip weapon you're using to make the trip, you're using the weapon. Since it's finesse, you can use your dex mod instead of strength on attack rolls with the weapon.
You kind of have to go all over the book to put it together, but it seems straightforward once you get all the pieces:
Trip weapon lets you use trip action with the weapon, trip is an attack action, which calls for an attack roll, weapon is also finesse, which lets you use dex on attack rolls with the weapon.
Same applies to disarm.
Syllogistically, for Rysky :) :
1:
Trip weapons allow trip actions with the weapon.
Trip actions call for attack rolls.
Therefore, trip actions using a trip weapon call for attack rolls with the weapon.
2:
Finesse weapons allow for attack rolls with the weapon to use str or dex mod.
From 1, a trip action with a trip weapon calls for an attack roll with the weapon.
Therefore, a trip action with a trip and finesse weapon calls for an attack roll using str or dex mod.
So I'm going to disagree (and this is going to be a long post, warning up front).
First, the Athletics skill has strength as its key ability. https://2e.aonprd.com/Skills.aspx?ID=3. Per the CRB, you “add your modifier for this ability to checks and DCs when using that skill. https://2e.aonprd.com/Rules.aspx?ID=171. This ability is referring to the key ability. Although the CRB indicates that a GM “might have you use a different ability modifier for a skill check,” it is up to the GM to deem it appropriate for a certain situation (so no set rules for substituting ability scores).
Second, the Athletic skill includes several activities that you can perform that have the “attack” trait, such as Force Open, Grapple, Shove, Trip, and Disarm. https://2e.aonprd.com/Skills.aspx?ID=3. The Attack trait indicates that “an ability with this trait involves an attack” and that “For each attack you make beyond the first on your turn, you take a multiple attack penalty.”
So far we know that Athletics allows you to perform several tasks that have the attack trait (e.g., involve an attack) and that you roll an Athletics check with your modifier being your proficiency plus your strength. Now, looking at weapons with the finesses trait, we see that finesse provides the following: “You can use your Dexterity modifier instead of your strength modifier on attack rolls using this melee weapon. You still use your Strength modifier when calculating damage.” So, two important pieces of information here. First, Dexterity is substituted for strength only for “attack rolls” and second, even if you use Dexterity for an “Attack roll” you still apply strength as normal for damage. The second part is important because it implies that Dex does not get automatically substituted for all instances that use Strength when using a finesse weapon. Instead, Dex is used only when you make an “attack roll.”
So, what is an attack roll? The CRB at page 446 states that “When you use a Strike action or any other attack action, you attempt a check called an attack roll.” Ok, so not really helpful, as now the question moves to what is an “attack action”? This term is not defined in the CRB, so we have to do a little digging. First, we know that a “Strike” action is one type of attack action. Second, the multiple attack penalty applies any time you make more than one attack action during the course of your turn. So far, nothing definitive on whether an “attack action” includes Athletics tasks.
However, when reading the section on Armor class, the CRB states that “Attack rolls are compared to a special difficulty class called an Armor Class (AC), which measures how hard it is for your foes to hit you with Strikes and other attack actions.” So now we see that an attack action includes an attack roll that is compared to AC. Going back to the Athletics tasks that have the “attack” trait, each of those tasks are compared to a fortitude DC (Grapple, Shove) or a reflex DC (Trip, Disarm). None of the Athletics tasks are compared to the target’s AC. Therefore, athletics tasks do not include attack rolls, and therefore the language of the finesse weapon, which only applies dexterity to attack rolls, would not apply.
Finally, the traits that allow you to perform an athletics task with the weapon, such as the "trip" trait, only indicate that "You can use this weapon to Trip with the Athletics skill even if you don’t have a free hand" and that you can "add the weapon’s item bonus to attack rolls as an item bonus to the Athletics check." So again, this differentiates attack rolls and Athletics check for these athletics tasks. If the Athletics check was an attack roll, the weapon's item bonus to attack rolls would automatically be added and it wouldn't need to be specified.
Therefore, you cannot use your dex modifier in place of your strength modifier when attempting an athletics task, even if you are using a finesse weapon with the corresponding trait.
*TL;DR: Athletics tasks (trip, disarm, etc.) are performed by rolling an Athletics check, which is not an attack roll, and therefore you cannot substitute Dex for Strength even when using a finesse weapon.
So to take your Syllogistical approach:
1)
Attack Actions include an attack roll
Attack rolls target AC
Trip attempts are Athletics checks that target reflex DC
Thus, trip attempts do not include an attack roll and are not attack actions.
2)
Trip trait allows you "use this weapon to Trip with the Athletics skill even if you don’t have a free hand"
Trip requires an Athletics Check (not modified by trip trait)
From 1, Trip attempt is not an attack action.
Thus, trip trait does not allow you to use Dexterity for the Athletics check
