I'm not sure what "general anti-magic" is, but that's at least as big as a minor focus. PeVi is "general antimagic," which is bigger than a minor focus by definition. "Destroying magical effects" is a fine minor focus. And your player probably wants to include wards against magic too!
Intangible Tunnel isn't abjuration at all, but what the heck.
Ovara - Abjuration is essentially a subset of Rego Vim, with a generalized countermagic guideline thrown in for fun. The list described above was me mapping the guidelines on RoP:D, pg. 48, to hermetic guidelines. And specifically - yes, Abjuration does have (holy) intangible tunnels. "Open a spiritual portal between you and a supernatural being within range, allowing you to see and hear each other for the duration of the effect." - I've always read that as functionally being an intangible tunnel, with a communication element thrown in. (albeit Voice and sight-based.)
Dispel magic (1 general PeVi effect)
summon supernatural creature (3 separate but really closely related ReVi effects )
Temporarily create a holy connection (Holy Magic's version an arcane connection) (1 General CrVi)
Bind supernatural creature (lvl 5 ReVi effect)
Create a supernatural connection (1 general ReVi)
Ward vs. supernatural creature (General ReVi effect)
Bind mundane creature (lvl 15 ReAn effect)
Bind Human being. (lvl 20 ReMe effect)
So to be technical, that's 10 guidelines; I'm personally fine with dropping the last 2 (they don't especially fit the character) - and the "summon supernatural creature" guideline for Hermetics are all REALLY closely related. So that's essentially 6 guidelines.
In looking at the ReVi guidelines, there are 7 core guidelines, and 12 extended ones (yes, many of the extended guidelines are really similar). The extended can pretty easily be collapsed into 3 or so additional guidelines (summoning, activating an enchantment, and specific magical suppression).
So...yes. Now that I have my books in front of me (the original list was done from memory), it's slightly over 1/2 a TeFo: 6 guidelines in the Focus, vs. 10 in the TeFo.
EDIT - and both "summoning spirits" and "controlling spirits" are both really weak foci - the first is essentially 3 vim guidelines, while the second is 1 vim guildeline. While I'm sure they count, I personally would want something a bit more useful. The upper guideline for a minor is "half a TeFo" - the upper guideline for a Major is "half a Fo". What you are describing as legit minor Foci are nowhere near that. If that's the way you play your game that's fine - I prefer something a bit more substantial.
Oh, and for those who want to know the definition of "Abjuration" (edit - is it Adjuration? That's what it's listed as in my book. I'm guessing that's a typo...huh. No, that's the name):
"Adjuration is the Power to summon, control, and banish supernatural creatures of all kinds, including dispelling their powers and compelling their cooperation....[it's] also the power to enforce and witness oaths..."
Which I totally agree sounds like a lot, until you realize it's essentially half of Rego Vim, plus that countermagic bit.
I'm not at all swayed but I'm not the one you need to convince.
The stuff being asked for is wide. Summon, control and banish anything? Each of those is a full Goetic technique. Maybe better. Oh, wait, and you can bind too. Wee.
Temporarily establish a "holy connection"? Yowsa.
Then you add stuff that's not Vim at all.
Oh, and now dispel magic for some PeVi action.
My inclination is not to allow this even as a major focus. I think it's too wide, I think it's too much, and I think it isn't focused: When someone tells me what their magic focus is, I really like to have a good idea of what is and is not included. To the extent I need an explanation or a list of rules, I go yuck. "Abjuration" goes to great extent and then some. And then I take a breath and remind myself that it's better to say yes when possible, because it is too easy to shut out other perspectives, and isn't that the point of a collaborative game? So, ok, a major focus.
But minor? lol I don't think so.
Again, however, I'm not the one who needs to be convinced. (And fwiw, I consider "ships" to be a minor focus, even though an actual AM book thinks it is major. So mine is hardly the only perspective!)
All of which are already covered under 3 closely-related ReVi guidelines (which has 10 general guidelines) - so I'm really not seeing anything Wide here.
...which from a hermetic standpoint is a closely-related technique to summoning, yes.
Yes, which I pulled out of this MMF, as I don't particularly think it's necessary for the character. Call it "spirit Adjuration", if you like.
shrug - at the end of the day,
it's strongly conceptualized based on an existing, canonical Power,
the actual guidelines used are almost all within a single TeFo,
the number of guidelines used is essentially 1/2 that TeFo, plus a single outside guideline. (which is allowed under the RAW).
That's ultimately the hard rule we've got - "slightly narrower than a single TeFo" (AM5th, pg. 46). That's well within the RAW. As such, yeah - I pretty much disagree with you on that.
But yes - I agree that it sounds broad, until you look at the mechanics, which show that hermetics don't really consider these abilities to be significantly different.
Perhaps that's where the disagreement is: I look at the mechanics as a guideline for how hermetics (and the gameworld) implicitly view things. If things are closely-related in game mechanics, that strongly suggests that they're closely-related in the game world. Of course the opposite isn't necessarily true (sometimes separate elements can be related conceptually - necromancy touches ReCo, PeCo, as well as ReMe for ghosts, for example). But by and large: yes. If something is related conceptually in a Power, AND most of those powers can be described by guidelines in a single, focused TeFo...then yeah. To me, it's probably a MMF.
Note that this wording would tend to weaken the "general anti-magic" item by quite a bit. Under this definition, the focus should be limited to dispelling and warding against the powers of supernatural creatures, but not against those of human practitioners of magic (such as Hermetic magi). The same is true about "general wards" and "intangible tunnel" -- it would apply only to tunnel effects targeted at supernatural creatures, not mundane ones et even magi.
I understand the objective of the focus, but the list of effects you propose need to be limited strictly to target supernatural creatures. Otherwise it turns into something that is much wider and far less thematic, I think.
In general, I think that the thematic aspect of a focus is much more important than its mechanical ones. The extent of the theme simply helps to determine whether the focus is minor or major. The minor vs major nature shouldn't be used to justify including this or that guideline under the focus. (I don't think that is what you are trying to do. I simply think that your mechanical approach is leading you slightly astray.)
So I think you should concentrate on the theme's definition ("summon, control, and banish supernatural creatures of all kinds, including dispelling their powers") rather than consider the number of guidelines. Consider the fact that the proposed focus will affect supernatural creatures from all 4 Realms. That is quite wide, covering significant parts of 2 Te+Fo combinations. Personally, I would consider this acceptable as a minor focus in some sagas, while it might be major in others.
A final comment regarding the applicability of a focus. It can be applied in the lab only to effects that are strictly limited to fall within the focus. So it wouldn't apply when inventing a standard Opening the Intangible Tunnel. However, when casting that same spell against a supernatural creature, the focus would certainly apply to the casting total.
Kinda, yeah. But it's a Divine/Dominion Power - and I trust we all realise the Divine cheats that way.
More importantly, I don't see it fitting under a single concept. And to my understanding, that's the central idea of the Magical Focus.
I would simply not allow this at my table (or rather, vote against it, since we play a fairly pure troupe style).
I don't really care about how many different guidelines it uses, there are too many too different effects here.
Technically, Holy Aduration is a Holy Power - you don't need to learn a single spell, you use the Holy Powers directly.
To quote HoH:MC p102 under the Followers of Pendule "and Pendule Merinitae often learn Spell Improvisation or a Major Magical Focus in counterspells" - so at least one canon source suggest counterspells (which sounds like antimagic to me) is a Major.
Abjuration, as described by the OP, seems so wide I'd be very wary about allowing it as a focus unless everyone's being allowed a lot of slack on Magical Focus, flaws like Restriction or Necessary Condition, or are being allowed Death Prophecies.
The original thought wasn't antimagic, but rather the specific "general dispel effect" guideline that mapped to the Abjuration version. Actual Antimagic covers a number of PeVi guideline - this covered one.
Again - that list up there was me mapping specific guidelines to the Adjuration Power to Hermetic guidelines - not a list of general techniques I wanted in a focus. (so, it was "1 PeVi antimagic" effect, rather than "all the PeVi antimagic effects").
If "countermagic = PeVi antimagic" then that interpretation violates the "slightly less than a TeFo" rule of a MMF. That sounds more like "Countermagic = spontaneous spells cast defensively", which make sense considering the other recommendation that you describe.
Again - all the effects in that list were references to specific ReVi guidelines, plus a single PeVi guideline.
I think Intangible Tunnel is outside the rest of it and shouldn't be part of this category. Holy Abjuration is its own thing and doesn't necessarily map to Hermetic categories. Otherwise, it'd be...essentially a slightly-trimmed focus in Rego Vim (among other things, it'd apply to the Aegis). So it'd be Minor.
That makes me think of using Ars Goetia as a Hermetic Focus...
Though late in the discussion, I'd just point out the fundamental difference between aDjuration and aBjuration. Though they sound almost identical, they are actually almost the opposite. The prefix "ad" means "towards", whereas the prefix "ab" means "away from". So when you adjure spirits, you summon or entreat them (literally, you "oath them forward"). When abjure spirits, you banish or forswear them (literally, you "oath them away").
This said, to me it seems that the proposed focus is not sufficiently narrow, and more importantly not sufficiently coherent, to qualify even as a major focus. Adjuration or abjuration of a particular set of creatures/things (a set large enough to be a major focus if taken in its entirety - say, spirits) would probably constitute a fair minor focus, however.