So we saw that one coming.
But what if that character buys an Armor Piercing knife? Right now Armor Piercing in JAGS is defined as: if the armor fails a save it does not apply at all. This sounds horrific but statistically it's good but not that good (it turns out that, mostly, you are not failing Armor Saves against at-level attacks). But still: that makes the guy's Armed STR even better. Doesn't it?
Yes: it does.
So how do we handle that?
Well, there are two basic ways:
The Basic Game
We don't care. You don't care. JAGS is too complex already. In this case you will either (a) not worry about it or (b) we will have some table somewhere that converts "armed STR" to "Armed AP" STR. We could do that and, if you cared, you could look it up. But we might not get everything. We might miss ... Ignores Armor Phantom Blade stuff ... or Soul Stealing Strength or whatever.
In fact, it's likely we would: there's going to be a really stunning number of attacks and having conversion tables for all of them isn't likely.
So if you care ...
The Advanced Rule
All these attacks will have a Factor associated with them (a decimal number) and you should be able to multiply your normal STR by the AP Knife's Factor to get the actual damage. This will be done in the case where something like a GAT gives +1 to ranged PEN damage ("Gunslinger") but you are firing something like a Disintegration Ray (in which case each level adds something like +.20 damage).