These are the spells few games if any have ever implemented except for the most basic like detect magic (that nwn itself did away with)
They're supposed to be the weakest spells, and the truth is nearly ALL the information the spells could give you, the GUI itself gives you. So to implement a lot of these spells you have to BLIND the general player so to speak so you can reveal the information only to those who should be recieving it.
Theres also a few of the hardest if not most impossible to implement spells on any CRPG. Thats what I call a challenge so i'll TRY to bring up some possible solutions. ALL of these solutions require a HUGE amount of work and probably wouldnt be worth the time or effort, though I'll put the ideas up anyway just incase you're feeling like a challenge.
Section 1: Languages The arcane spell comprehend languages, toungues make big use of this. This is massive can of worms, you have written languages and spoken languages. Spoken languages: To do this you need to be able to store on the character the languages they know, then give them a way to change to speaking in that, or give them a pre-command like: [e] Hello friend. What the code would have to do would be to then substitute the letters afterwards with some sort of substitution cypher. For elven you might make a passable conversion by turning the letters into lots of vowels. orcish might look ok with lots of k's apostrophe's s's, h's, r's etc. After you do this conversion you need to make that said in public. Then send the original text to the people in audible radius that KNOW the language (maybe as a tell or in the yellow dm text) As you can see this is non-trivial. written languages: Involves the same routines but this would need to be done in the examine code and then convert the text to gobbledegook if the reader could not READ the language. You could have a hidden [e] on the beginning of the text to say that's the language (elven in this case) it will turn it into if the reader doesnt know the language. You can have texts with multiple languages on them, the hidden [d] or [o] etc would turn it into dwarven or orcish etc.
Part 2: Location spells Locate person, Find the path, location object, Discern Location (and scrying) all need to find things. These spells have a distance radius. An interesting implementation would be to make a scripted creature that actually travells invisibily through exits etc and LOOKS for the object in the map. It could possibly just go 2 or 3 steps away before it backtracks and tries other avenues. Once it's found it, it can return the data to the caster (and in the case of scrying it can turn of a possession visual mode of the scrying device) Arcane eye would be using the same scrying code with the possession of an invisible "eye" by the caster. Prying eyes would be the same though there is multiple eyes in motion that you must be able to cycle through somehow.
Part 3: Blinding the user for effects By this I mean turning OFF gui elements so you can REVEAL that information for those in the 'know'. Already the examine person on EFU does not show statuses. So the spell STATUS would turn this on when you look at party members. You could also have spells for getting information on creatures as well. Like level 6 cleric spell Analyse dwellomer. Level 5 arcane: Telepathic bond this spell is actually just /p.. party speak.. so you'd have to disable /p (or erase the outputs) except when somebody in the party had this in operation.
Part 4: the almost impossible spells Discern Lies, Detect thoughts you can have these working on NPC's you can put certain special character mnemonics in their written text or something to show other information for when these spells are active. <lie> I didnt do that believe me {he's lieing}> etc. The only way to have this work for players is for the players to be complicit in it, so the game would annouce to people around that this person is "discerning lies" or "detecting thoughs" so the player could add extra information to their written texts. This needs good and BRAVE roleplayers to have it work, knowing that lieing to the wrong person could get your character killed ;)
The other 'impossible' spells are Contact other plane, Augury and Commune. These would NORMALLY require a d.m for it to work at all. You'd need maybe an item called "augury" in your inventory that you cast any level 2 cleric spell on and it would either fail for being no d.m or send a special message to the d.m's that requires a result. If theres no d.m's on then it cant be done. With PRESCIENT spells the only way to implement them is to randomly determine the result of the action before then FORCE the result when the time comes. "Will I die when I try to disarm this trap?" <roll 5% death chance> <result WEAL> So the trap becomes TAGGED to be disarmed because it's already done the roll. So when the ASKER goes to disarm it, it does. If the result was WOE then if the asker does try and disarm it, it will go off. (what a fool :) )
To do this sort of thing in scripts, because they're open ended question unless it's d.m run you need SPECIFIC sub questions that you can ask. 1) Is it safe to disarm object Y? 2) Is it safe to walk to X,Y? 3) Is <insert common question>? 4) Open ended question <NO DM ONLINE>.
A lot of these options for augury, commune etc can lead to code in the earlier parts i've talked about. (like using location object code) To determine if it is safe to walk to x,y, the script needs to make an invisible ghost copy of the caster, then walk it to X,Y, determine any traps set off etc. Then answer based on that. And also preset the results on those traps (but only for the caster) Augury JUST returns WEAL and WOE (but also has to SET the future) Commune and contact can return extra information about what traps they are etc. (again all the divination spells have to SET the future when they give a result for that foretold result to be true)