If I wanted to sneak into someone's covenant it seems very easy. What spells and effects have people used to enhance the security of a covenant beyond just the Aegis.
I keep thinking of big boundary detection spells for corpus but all of those would bounce off of Parma so they wouldn't really be solid security.
There is a mind reading door in MoH that shakes when someone who means to cause harm enters. But that seems like no big thing to bypass.
It would also warp everyone in the covenant, wouldn't it?
There's the usual list of defenses: Post guards, give guards magical items that can apply detective effects, deal with a local spirit or faerie to help watch. An older character of mine enchanted the flagstone of his sanctum entryway to detect creatures, animals, and people standing on it. The intent was to teleport the wrong people outside again, but I never finished it.
The classic anti-Parma device is an enchantment with a linked trigger if it can't detect certain information (for example, a door that tries to read the opener's mind when it's opened to see if they have malicious intentions towards the covenant - if they do, there's a linked effect that triggers, if it can't get a reading, ditto).
Well, doesn't Aegis prevent any magic from entering its area of effect, either through spells or enchanted devices, much the same that Parma does? So if someone were to try robbing the place, they'd have to do it without the use of magic...which is a massive deterrent in itself, right?
"Hey, I'm gonna rob the place tonight."
"Um, you know you are gonna have to do it without that magic lockpick, right?"
"Oh, right. Um, I think maybe I'll just head to the tavern and have a few ales instead."
You need to penetrate if you go across it and you have penalties inside it. But perdoing my self invisible is easy. Teleporting is harder but not hard to cast really if you can teleport to the edge walk across and teleport some more you are good.
If you're planning to take security measures against magi, don't forget that scrying is a crime, for both parties.
I won't go further about it, it's slightly off-topic.
Aegis is quite a good security measure. It keeps creatures with might out of the covenant and causes big problems for any practitioner of magic (provided it penetrates).
For other people and creatures, you have those Rego Corpus impassable rings, mind-reading spells with no penetration (out of your sanctum, don't use intellego spells which react if resisted, it's scrying!), other barriers needing magic to pass (such as some part of covenant with no door at all for instance) and, if needed, traps specifically designed to kill, maim or capture magicians (the trick is to have them cast a Perdo Vim spell, that springs a mundane trap).
You should have a look at the sunken lab of Hermanus in "Hermetic Legends" (or is it (serfs parma) Legends of Hermes ?)
A lot of Anti-wizard measures would be things you set up once a Wizard War is declared. Sanctums you can do what ever you want, they forfeited their rights by coming in.
But in fairness I was probably planning on doing something illegal if I'm trying to think of ways to sneak past security systems.
Ya, I was sort of underselling Aegis. But I think a lot of people underestimate low level magic. I can mine a tunnel under your walls spontaneously through your Aegis because destroying an individual of earth at touch range is a level 4 spell, stone is 5 so unless you have steel walls anyone can dig through. Turning invisible, a little harder at level 10 (might need to actually learn the spell). Flight, two level 5 spells (one to go up one to go sideways). I tend to underestimate teleportation difficulty since I always make good teleporters, but level 15 (50 pace) is still really far (from the middle to the outside of a canonical Aegis as it happens). Basically all of that basically any magus can cast inside an Aegis spontaneously (except the teleport). There aren't really good defense other than you will know they are there by the man-shaped holes in your walls leading to your chamber pots.
I take it "the sunken lab of Hermanus" is something like an Ars Tomb of Horrors. It would be good to look at.
Cleaning up your Arcs is probably one of the best defenses. PeCo (or is it Te at that point) ring spells on your chamber pots (because why wouldn't you). Immaculately Groomed Magus spell to clean up hairs and skin every morning. Having enough Magic Theory to know In Character what things are likely to form connections to you and PeVi'ing the connections. I have worked in a laboratory setting, magically sanitizing your equipment is no more arduous than doing the dishes (especially when you actually did the dishes by passing them over a PeAq(Te) ring spell).
But this did answer my question. the concept of "Detection Spells" that would need to be avoided is basically a myth. Unless you are also legally justified in downing their Aegis and marching (Marching) in with a force of Hoplites.
I do like the keeping Spirits around. My guards are already Intelligent Hounds so an invisibility spell has to hit smell. But Faeries are very good at seeing through illusions. My thought on Undermineing makes me think I should really have out Elementalist Companion make some land sharks to "swim" through the foundations of the covenant to watch for intruders.
Some ideas:
The covenant is in a Regio, making it difficult to access.
For a smaller library, have apprentices fix AC's for all the books, and keep them somewhere outside the library.
The Flambeau in the lab may have a deterrence effect.
Clear anything of value out of a lab before a wizard's war (does not work if entire covenant is decced).
There's an aspect of a daemon familiar watching the items.
Moon duration spontaneous spells using ceremonial casting and props.
The covenant is in a faerie aura. The book you just stole is actually a faerie (contents are actually faerie lore or faerie alinged hedge magic, regardless of what they first seem).
Hedge magic to curse theives.
The covenant is dangerous for those that don't know it's quirks.
The vis is wrapped in a cloth in the store closet. The large locked chest in the council room contains a bunch of deeds and maps.
Spirits, ghosts or physical undead.
A device that teleports all books back to their correct spot in the library at the start of each season.
Bloodhounds.
Magical bloodhounds.
Guards.
The covenant is a fortress.
Contact poisons.
Wealth in the form of land and labor.
Unnatural laws on the site detering theft.
The items are hard to find. For example a small hermetic library mixed in with a large library covering theology and canon law.
Many of those seem like really hard things to control.
My covenant does have something like the Library idea you mentioned. To control copies we have AC's to them and a magic axe that can destroy the books over an AC if they are ever stolen.
Two other possibilities involve looking not at the present, but at the future. Minority Report in Mythic Europe!
The Premonitions Virtue is great, while still being ... Minor, and thus "groggable".
One can use mundane Astrology to find out if, when and how your covenant will come under a sneak attack. See pages 73 and 74 of A&A, and in particular the inception "Who was the cause of the death of N"? Inceptions are expensive timewise (they require seasonal activities) but again, they can be carried out by any grog trained in Artes Liberales, even a perfectly mundane one!
Love of Christ I'll get around to reading that book some day...
Of course, the best security would be placing your covenant somewhere inaccessible to mere mortals. Consider setting up shop in a Regio, or gratuitously underwater, or about a mile high in midair. The Scholomance in Against the Dark is a fine canon example, being atop a mountain and only visible against the flash of lightning.
The traditional sanctum protection has three stages: First, a warning. Second, a nonlethal deterrent. Finally, one or more lethal ones.
In my humble experience, the primary defenses on sanctums are:
But I know players are more creative than me. You may find this NPC helpful; he is a Tytalus whose profession is breaking into sanctums. I gave him a bunch of spells and effects to do this, and you can see from what I gave him the kind of security measures I anticipated.
for a generic thief, one of my favorites is setting out a MuIg(te) spell transforming a bonfire into a gem with a duration ring. Then if they try to steel the gem it turns back into a bonfire in their possession. It does rely on the thief being willing to grab a target of opportunity, but aside from that pretty effective.
I like the failure to detect thought idea. You could then include non-magical attacks, like using that to magically break the ceiling above it, which might have been holding lots of nasty acid in place in a circle, or something like that.
I like silveroak's gem for that, too.
Scrying is a crime, but the Guernicus House book states scrying to detect eg invisible wanderers in a covenant is unlikely to be seen as a crime. Defending yourself against thieves or attackers is reasonable, and unrelated to the reason scrying is banned: to protect the secrecy of a magus's magical projects.
Edit: I add Hroppa beat me to it. Good catch!
According to HoH:S, the use of scrying magic to detect attempts to scry on you is generally permissible under the code. The use of magic to detect attempts to scry on your covenant is also generally acceptable, because it’s hard to mount a legal defense when your hand is in the proverbial cookie jar.
Since the definition of scrying under the code can include any use of magic to spy on other magi, a spell that detects invisible things within your covenant is probably legally defensible. The invisible wizard would have the same challenging legal battle that someone in a bank with a bag full of safecracking equipment would have- even if it’s technically legal, the time and place make it very unlikely you weren’t in the process of breaking the law.
So magic to detect things that are inherently unlikely to be used in your covenant in a legal way, like invisibility or mine reading magic, are probably appropriate defenses.
Also, if this is to protect your sanctum, you are given far more leeway.
My Merinita is considering having the phrase "By entering this sanctum, I promise I shall not take anything not freely given," onto his sanctum door.
You get some nice penetration bonuses for Bargain duration spells.
I'm not sure that would work for bargain duration, since agreement is implied rather than actively given. Such "agreements" are pretty weak even in modern law, and unheard of in Medieval law, and weaker still on the less legalistically inclined.