[Stainless Steel Devil Rat]

I believe I have my mind wrapped around the Astral/Physical planar "barrier" as it exists in the in-universe "metaphysics".

One question I don't feel completely confident on:  Can an astrally projecting security mage/shadowrunner give counterspell/give spell defense to teammates on the Physical plane?  It seems like the way I understand 5th edition is it'd violate the "you have to be ON the plane you're affecting" rule of thumb, but I don't see anything explicit allowing or disallowing it.  Hoping one of the helpful forumites can point out what I've missed, or failing that see some sort of measure of where opinions lie.

[Overbyte]

My thinking would be.. if you wanna protect someone that is dual or astral you could, but not someone who is not.
And you couldn't protect them from an indirect spell in either case.

[Reaver]

It doesn't say outright, which is indeed annoying. But when you look at what is actually happening (the mage is trying to disrupt the mana of a spell before it goes into effect - thus reducing the effects), then I believe you would have to be on the same plane as the target you wish to protect.

OTOH, it does really affect game play as its something the NPCs could do as well...

[ShadowcatX]

Shadowrun is set up in such a way that if you don't have a rule allowing you to do something you can't do it. There is no rule allowing cross planar spell defense.

[Stainless Steel Devil Rat]

Shadowrun is set up in such a way that if you don't have a rule allowing you to do something you can't do it. There is no rule allowing cross planar spell defense.

Of course the flipside to that critique is that the rules for spell defense say you CAN perform spell defense without any caveat about needing to be on the same plane as the target or even whether spell defense "targets" the incoming spell or the targets of said spell for the purposes of determining presence.  It also doesn't say whether you can "sustain" spell defense allocated prior to projecting to the astral plane (as I'm pretty sure you can cast a spell prior to projecting then sustain it from astral space)

That being said, yeah I think the mage does need physical presence to protect physical victims of spells.  In my view there's an argument to be made in spells having an inherent Astral presence by virture of being ephemeral constructs of pure Astral energy... but I'm not sure I like the wider implications of an astral mage doing overwatch for a team while being untouchable from the physical plane.  Absolutely seems to go directly against the intent of the astral presence general rules.

[Overbyte]

Truthfully the first thing I want to know about Spell Defense is how you even do it?
How do you even know you need it? Do you have to make a perception roll first?
Since you really have no clue how "big" the incoming magic how do know how many dice should you use?

NOTE: I generally don't worry about this much in my game, but it is really annoying that it makes so little sense.