The idea was to make them tools that're just called "x potion" then make a boiling stone reaction that consumes the potion. That way people can drink them even if they aren't thirsty and people don't have to do crazy stuff with burrows to get the right person to drink them, just assign them to that workshop with the manager or disable the alchemy labor for everyone else. The invisibility one would work by giving the creature access to an interaction (using (CE_CAN_DO_INTERACTION]) that gives them the hide ability. The usage hint would be blank, which if I remember right makes the creature use it whenever it's available. Just gotta make the cooldown shorter than the duration of the effect and that's that.
A side effect of doing it that way is that people could burrow their entire fort on the workshop tile and give everyone the potion's effect, but given the negative effects of these that probably isn't the smartest plan anyway.
Boiling stones don't actually work all to reliably without DF Hack do to "breathing ticks" (65-75%?)
http://www.bay12forums.com/smf/index.php?topic=154562.msg6659549#msg6659549.
I actually had a possible solution that's posted in that link, but I can repost it if requested.
I think that his numbers are probably a wee bit off given a comment at the bottom about how often the effect works.
As to this, "The usage hint would be blank, which if I remember right makes the creature use it whenever it's available. Just gotta make the cooldown shorter than the duration of the effect and that's that." What I noticed in arena was that it wasn't used on self as often anymore. If I could make a suggestion? Use two, usage hint "greeting" and usage hint "attack_only(or whatever the actual thing is)." That way they'll be forced to use it in the only 2 situations they'll find themselves in.
Edit: My solution to large groups, which I posted in the thread, is theoretical, but might work.
Found this thread while looking into implementing an alchemy/magic system of some kind.
Now, I'm a novice modder at best, so forgive me if I've misunderstood something, or made incorrect assumptions about something, but I think I have an idea that might work. It's only a theory though.
It seems to me, based on reading this, that the issue with applying a syndrome through inhalation is that due to the breathing tick, the target creature can only inhale a small number of times, as the gas fades before they have another chance to breath it in. Even when generating a large number of boiling stones, the gas still fades away in relatively the same amount of time, correct? And IndigoFenix's work around gives multiple chances for the effect to work, but runs multiple reactions.
My theory, I believe, may work relatively well. If you could extend the amount of time there's gas in the air, it would give the creature more chances to breathe it in and be affected. Containers affect the temperature of their contents, raising or lowering them depending on it's own temperature. What if you had the reaction produce a number of stones and place them in a container with a fixed temperature just over their boiling point? Give each stone a different spec_heat value calibrated so that when the gas of one dissipates, another one boils(would require testing to get the time right). Or better yet, have multiple clones that boil simultaneously so theirs a greater chance of the inhalation happening. This way, the air is full of syndrome-gas for a longer amount of time using one reaction, giving a more reliable(not 100%, unless you do it for a very long time, but close) rate of effectiveness.
There's a mod that covers weapons in adventure mode, if I recall.
Double Edit: The mod escapes me! Nooooooooo... Well... I see 2 possible ways to do it then. Weapons made of a material that melts inside the creature.
Or.... momentarily give an interaction to the user that can target a material, and tell it to fire the poison at it..Or give up.