...yeah thatwas the idea. So if teh arm is her primary hand does its Agility rating for that count for the pool when she's using her pistol?
Cyberlimbs inherently rely on GM's whim, so that's a turn-off for some in SRM since there's the potential for a GM you've never played with to view things differently than you/your past GMs.
So the way it works is this:
Cyberlimbs have their own Strength and Agility ratings.
When a particular limb is used for a test (such as
leading an attack with your cyberarm), use the attribute
for that limb (natural or cyber); in any other case, take the
average value of all limbs involved in the task. If a task
requires the careful coordination of several limbs, use the
value of the weakest limb. The attributes of partial limbs
(including cyberhands and –feet) may be enhanced, but
their attributes only apply for tests directly involving
those limbs (such as a Strength Test when gripping something
with an enhanced cyberhand).
There's a good bit to unpack there. The first GM whim is determining whether the task you're doing can be done solely by a single cyberlimb or not. The next whim is "if not", then what limbs are involved (and just as importantly which are not) for the purposes of averaging the attributes across the parts of the body involved in the task.
So taking a break to digest what we have so far: If you go to thwack someone with a Katana, you might have one GM say you can just use the stats of one arm. The next GM might insist katanas are meant to be used two handed, and you have to use two arms. The third GM might say that not only do you use two arms, the two arms can't perform a task together without the foundation of your core, and since the torso is a potential "limb" as recognized by the cyberlimb rules, you average 3 'limbs' in the two arms and core body. Etc.
The next whim is whether or not the task involves "careful coordination of several limbs". If so, then there's no averaging but simply using the worst value of any body part involved.
Then finally another GM whim is triggered in the event you do partial limb replacements as to whether or not the task can be done by a partial limb.
Something I find of interest is how Chummer calculates AGI/STR when you have cyberlimbs. (I bring it up since it appears you're using it, too)
Chummer treats the body as having 6 limb slots (4 limbs, torso, skull) and gives you an augmented AGI/STR value based on averaging across 6 'limbs': 2 arms, 2 legs, torso, skull. Bear in mind the rules don't actually call out an augmented bonus to AGI/STR based on cyberlimbs, so Chummer is kind of reaching. In giving an augmented bonus, what it's really doing is showing you what your average stat is if the task at hand is averaged across all 6 limbs, including the agi/str of
your head!. The GM deciding a task involves all 6 limbs is slim. And if the GM invokes "careful coordination between limbs", you just go with the lowest. If that's your natural stat, it's just that. There technically is no augmented bonus (unless it comes from something other the cyberlimb)
Chummer example: say you have an AGI of 2, but you buy a single cyberarm and end up pushing its AGI to 9. Chummer will show your AGI stat in the attributes block as 2(3), and down in the gear it'll specify your Cyberlimb as 9. If you go to shoot a SMG, and the GM insists you have to use 2 arms, you don't average 9 and 2(3) you average 9 and 2. And if the GM says shooting the SMG with two hands involves careful coordination, you just roll 2 not 2(3).