AI

[massone]

Threatening will set the peace counter to a new value if it is successful, effectively replacing the old peace with a new one, and will do nothing to if it fails, unless it fails so badly it restarts the war.
Extorting gold from the AI isn't really an issue because by the time they are far behind, it isn't likely they have much left or the player is winning anyway.
Spells might be a problem though.
A fairly simple solution would be that after peace, the AI sets the variable that determines if they want to talk to the player very low. Then the player has to wait after peace before they can threaten, trade, or otherwise talk to the AI, the same way he has to after a war declaration or breaking a treaty. It makes little sense though, why wouldn't they talk to a player after a peace treaty. So this is probably not good.
An alternate solution would be to alter threatening to always fail during peace but peace being invisible that might not be a good thing either.
A third possibility is to use the same solution as used for finding spells from banishing the wizard, in the end, threatening and banishing are similar game mechanics in the sense they work against enemies weaker than you. This one even makes sense - if they offered the best they could in the past and it wasn't enough to make the player stop harassing them then why would they do it again? So the logical reaction might be to offer gold instead the next time which is not a problem for game balance - A cornered AI has little gold to spare and the low gold might even make the player angry enough to attack the AI's fortress unprepared and lose significant forces, effectively losing the game to the already defeated enemy anyway.
I think I do like this one.
We could even make this more detailed and add a condition : if you banished the wizard, they won't give you a new spell by threatening either because they know it'll be used against them in the end. Question is, do we want to connect this to the AI offering a spell when they ask the player for a treaty?

I would say that if the AI paid anything at all, and the AI is threatening to attack during a time which would violate the prior treaty, then the AI has no reason to believe the player will not simply violate the second treaty if they pay up a second time, unless they're truly desperate. So in general, they shouldn't pay anything if there is a peace treaty in place--but it's a problem if peace is invisible, so I think if that gets changed in the future versions or CoM 2, then this should be implemented. Otherwise, the third solution works fine. Actually, I haven't seen them offer me spells when I tested it. It's always been gold.

[massone]

Some new observations:

-You can threaten your own allies and get paid, with no obvious consequence, which is somewhat strange. I did have Charismatic though, so it might have halved the penalty such that I couldn't see the visible relations hit. Or is there a hidden relations hit?
-There is a point which overextension causes even allies to make threats about breaking alliance. I think this makes good sense, but I don't think it's documented anywhere in the overextension notes. This happened November 1414 when I had 33 towns on Huge Lunatic. That's 5 over the cap based on the formula. I've broken the cap while having allies on lower difficulties before and never seen this happen.

[Seravy]

There is no hidden penalty but if you miscalculate and land on a "start a war" result you lost your ally. The loss of 1-15 visible relation isn't much but it can hurt if you needed it for other purposes. (such as refusing your ally's requests of declaring wars. )
It also will make them not talk to you for a while so you are missing out on trade opportunities. If we make threaten not give more than one spell, that will be a significant downside.
They can warn you for any reason while you have an alliance with them, but typically the chance of the warning going through the necessary roll is low. It depends on the warning strength, the personality and visible relation. It's the same warning you'd get without an Alliance except the text is different and says "or I will break the alliance" instead of the usual. Likewise if repeated warnings happen, instead of the usual chance to roll a war declaration, they break the treaty instead. While the formula isn't in the document, the fact you lose the treaty is mentioned :

Warning based war
If the AI wants to warn the player for their misdeed, and they recently warned the player, there is a chance to escalate the warning into breaking a treaty or declaring war. This chance increases as warnings accumulate but decreases over time. However if relation is already below -75, a war declaration will be guaranteed.

I believe the reason you started seeing warnings is using Threaten.
Warnings have to pass the "do I really want to send this warning" roll, but if it's not a first warning then it passes automatically. Threaten sets the "warnings counter" to 1. (which is something I've changed in CoM 2 because it makes little sense for an AI to pay for their safety then be more likely to annoy the player and break their treaties.)

[massone]

There is no hidden penalty but if you miscalculate and land on a "start a war" result you lost your ally. The loss of 1-15 visible relation isn't much but it can hurt if you needed it for other purposes. (such as refusing your ally's requests of declaring wars. )
It also will make them not talk to you for a while so you are missing out on trade opportunities. If we make threaten not give more than one spell, that will be a significant downside.
They can warn you for any reason while you have an alliance with them, but typically the chance of the warning going through the necessary roll is low. It depends on the warning strength, the personality and visible relation. It's the same warning you'd get without an Alliance except the text is different and says "or I will break the alliance" instead of the usual. Likewise if repeated warnings happen, instead of the usual chance to roll a war declaration, they break the treaty instead. While the formula isn't in the document, the fact you lose the treaty is mentioned :

Warning based war
If the AI wants to warn the player for their misdeed, and they recently warned the player, there is a chance to escalate the warning into breaking a treaty or declaring war. This chance increases as warnings accumulate but decreases over time. However if relation is already below -75, a war declaration will be guaranteed.

I believe the reason you started seeing warnings is using Threaten.
Warnings have to pass the "do I really want to send this warning" roll, but if it's not a first warning then it passes automatically. Threaten sets the "warnings counter" to 1. (which is something I've changed in CoM 2 because it makes little sense for an AI to pay for their safety then be more likely to annoy the player and break their treaties.)

I might have remembered wrong, but I'm pretty sure I did the threatening as an experiment and immediately reloaded, as it felt cheap to use it. So I got the warning in the un-threatened save. About allies warning, there's this note from 5.28 changelog that specifies the formula, which is why it took me by surprise as I've been using the formula to keep track of overextension in all my games and actively planning to get allies before going over the cap:
Players exceeding this amount will receive a warning from all other nonallied, contacted wizards, that has a strength of (3+difficulty), plus 20% for each additional city they exceed that amount by.

So this isn't actually true then? Allies can warn you for any reason at any time, if you have at least 1 warning counter already?

I have to admit, I can't really tell what other reasons I might have offended them, but typically my allies only stay at "Harmony" for a couple of turns at most, they always go back down to Friendly and I don't know why. Might be a lot of hidden overextension warnings that counted as the first warning.

[Seravy]

Players exceeding this amount will receive a warning from all other nonallied, contacted wizards, that has a strength of (3+difficulty), plus 20% for each additional city they exceed that amount by.

Now that you mention it, yes, I actually remember seeing the "nonallied" condition when I was converting that part to CoM2.
Yes, it's there.

Are you sure it wasn't the warning message you get for banishing other wizards? It uses the same text group code unless the person you banished was an enemy of your ally.
Maybe it should get a new text group, now that I know it's possible to add one. But what should they say?

[massone]

Players exceeding this amount will receive a warning from all other nonallied, contacted wizards, that has a strength of (3+difficulty), plus 20% for each additional city they exceed that amount by.

Now that you mention it, yes, I actually remember seeing the "nonallied" condition when I was converting that part to CoM2.
Yes, it's there.

Are you sure it wasn't the warning message you get for banishing other wizards? It uses the same text group code unless the person you banished was an enemy of your ally.
Maybe it should get a new text group, now that I know it's possible to add one. But what should they say?

That might be it then. I did just banish a wizard and they were not at war with that ally. The text said something like "You are growing far too powerful. If you keep expanding, I shall have to break our alliance." I had another ally who was not at war with the banished wizard either that didn't say anything though.

Maybe this would work better: "You've gone too far! I can't just stand by and watch you banish a fellow wizard so casually! If you continue this aggression, I shall have no choice but to break our alliance."

[massone]

How does the AI determine where to put their new Fortress after casting Spell of Return? They seem to pick some really bad towns sometimes. Like a town that was nuked by Call to Void, fully corrupted squares, 5 pop, far from reinforcements or their other major towns, and right within movement range of my doomstack that destroyed their last fortress. I went away from the center of their empire because I couldn't hold any territory there, but they just moved their new Fortress over to Myrror, where they own half as many towns as they have on Arcanus. And of their towns on Myrror, only 1 hasn't been nuked yet, and for some reason they didn't pick that 24 pop well developed city 5 squares away.

[Seravy]

It picks the city with the strongest garrison.

[massone]

It seems like the AI hasn't been programmed to stop casting Spell Blast and Drain Power when there's a Power Link active. It's not that noticeable in most games because you don't get to see Spell Blast or Drain Power getting cast even when Detect Magic is on, but after I allowed an AI to cast Time Stop twice while I had Power Link active, it gave me the message about my Power Link fizzling their Spell Blast, and I saw that they repeatedly cast Spell Blast over and over until the end of Time Stop, wasting most of their casting skill.

[Seravy]

That's not an AI bug.
What I see written in my AI file is "Power Link has no effect during Time Stop so ignore it".

So it's a bug with Power Link, only the power producing effect is disabled during Time Stop when it should disable the countering as well. The AI works correctly, expecting this feature.