What are the contingency spell's limits in D&D 3.5E?

Question

Does a contingent spell's perception extend beyond the subject's perception? For example, can a contingent spell...

1. tell time?
2. read minds?
3. predict the future?
4. penetrate disguises?
5. discern the morality of actions?
6. employ senses the subject lacks?
7. determine other creatures' intents?
8. hear or see things the subject can't?
9. know if the subject's been robbed even if the subject doesn't?
10. otherwise be triggered by information the subject doesn't or even couldn't have?

Further, a contingent spell's trigger can be, "When I say, '[whatever],' activate the contingent spell." What's a good house rule for determining who says, "[whatever]," first when two or more creatures want to say, "[whatever]," simultaneously?

Answer 1

As written, contingency triggers as soon as its condition is true, not as soon as the caster is aware that it is true. Neither caster’s senses, nor anyone else’s senses, are involved: it just happens. The spell changes the fundamental laws of the universe such that the next time X happens, spell Y is cast.

So the question isn’t about who knows, it’s about what is fact. Going down the list:

 1. tell time?

Contingency certainly seems to be capable of responding to certain times (time of day, time since an event); the tricky part here is establishing the condition clearly. Many settings don’t have rigorously-defined times, so it’s not clear that “6 PM” is going to mean anything in-character. On a globe, time zone issues can also be problems. But something like “noon at Town” seems likely to work.

 2. read minds?

The open-ended nature of the spell leaves that conceivable, but I’d go with “no,” largely on the basis that personal thoughts are not “facts of the universe” and detecting another’s thoughts requires a Saving Throw. Contingency does not have a built-in read thoughts.

 3. predict the future?

Similar to how I feel about reading minds: predicting the future requires special, powerful, and uncertain magic. The future is not a fact, not yet, and so contingency cannot be triggered by it.

 4. penetrate disguises?

If the disguise included some form of hiding from magic (nondetection), then no, but a simple mundane disguise would not affect contingency.

 5. discern the morality of actions?

Magic can detect alignment without giving the subject a Saving Throw. Somehow, alignment is an objective observable reality. So things like “a creature of Evil alignment” and an “Evil action” could probably be valid. Whether or not alignment is the same as morality is debatable and beyond the scope of this question.

 6. employ senses the subject lacks?

Contingency doesn’t “sense” per se; it just automatically reacts to facts. So, basically, the subject’s lack of a particular sense doesn’t come into play.

 7. determine other creatures' intents?

Same deal as thoughts; probably not.

 8. hear or see things the subject can't?

Same as 6; it doesn’t “hear” or “see” but can certainly react to facts that the subject cannot hear or see.

 9. know if the subject's been robbed even if the subject doesn't?

Yes.

 10. otherwise be triggered by information the subject doesn't or even couldn't have?

The subject doesn’t come into play; it’s more about what “magic” could have the information. Protected information (e.g. stuff magic would require a failed Saving Throw to get) I’ll call unavailable, but even that might be wishful thinking on my part.

In short, contingency is horribly-broken as written. You can try to rein it in by houseruling in some limitations, but I’m not convinced they’ll be enough. The spell is almost-certainly the most powerful that Wizards ever wrote.

As for the timing of simultaneous events, the rules don’t really handle that well. Presumably you could just use whoever’s player declared the action first, but in the case of purely-reactive contingencies, both could be triggered by the same fact and therefore be “simultaneous.” For creatures’ actions, I’d consider houseruling an expansion of Initiative to use opposed Initiative checks in such cases. But contingency is not a creature and once cast, it doesn’t have anything to do with the creature it’s been cast on until it triggers a spell on that character. I think perhaps the best solution is to use opposed Caster Level checks?

Answer 2

Part 1:

By RAW, contingency (and by extension, Craft Contingent Spell) can do everything you list. The only restrictions placed on the conditions are:

The conditions needed to bring the spell into effect must be clear, although they can be general. ... If complicated or convoluted conditions are prescribed, the whole spell combination (contingency and the companion magic) may fail when called on. The companion spell occurs based solely on the stated conditions, regardless of whether you want it to.

This line does not mention any sort of restriction on what the conditions can actually be. By a strict interpretation of the RAW, contingency can cast a spell under the condition "if my mother will die in one year or less, cast light".

I would be the first to say that RAW in this case is really dumb. The rule I run with is similar to limiting it to the subject's perceptions. I say that you can use any personal condition or effect as a condition, like fire damage, or frightened, or "an attack that gets through my DR". I also allow anything that an unskilled level 1 commoner is likely to notice in the environment. You can have "when someone casts a spell within 20 feet", but not "when someone casts charm person on my allies", since the average commoner can't identify spells. This is all houseruled and judgement-based, of course, so it's best to handle it case-by-case.

Part 2:

Personally, I don't allow people to use their own speech as a contingency trigger. I feel that the intent of the spell is to respond to things in the environment, and not to activate extra spells on command with no action spent.

That said, the easiest way to adjudicate who says their command first is who physically says it first in the real world. If one player says their command a second after their friend, the friend gets the command off first. If the commands are simultaneous, a check would probably be a good idea. I would go with Initiative or Intelligence, but that's really up to you. As long as you're consistent, it shouldn't be a problem.

Answer 3

TBH, I think you're over-complicating the issue. If the problem is people activating contingency by saying something out of turn, and then having to figure out who said what when and how that impacts other actions... the simpler answer is to add a house rule like this:

Contingency can only activate from spoken commands during the player's turn, and not while in the middle of performing another action.

Alternately, just say Contingency never activates as a result of something done as a free action (like talking or blinking). Problem solved. When talking about house rules, I've really found that the keep it simple rule applies: making complicated house rules tends to lead to conflicts over how the rule is meant to work, and there's no large body of discussion on the Internet to help you sort it out (unlike the core rules, which do have that resource).

So a rule like my proposed one has the advantage of being simple and easily also understood. It also makes Contingency a bit weaker, which is a bonus.

IMO, the spirit of Contingency is meant to be reactive. It's "someone does X, so Y happens." It's not "I feel like casting a spell but without the casting part, so I'm going to just say hello instead." As far as I know there are no rules whatsoever to back that up, but it's how I feel they intended it.

If you really wanted to, you could make it function like a Ready Action that you've prepared ahead of time, and nobody would let you get away with a ready action to interrupt another character with the condition "I say something".