YesNoMystery
Lateral thinking puzzles with an AI answering yes or no
About YesNoMystery
YesNoMystery is the classic lateral thinking format, sometimes called situation puzzles, with a language model playing the part that normally needs a friend who already knows the answer. You pick a mystery, ask only questions that can be answered yes or no, and the AI responds and offers hints when you stall.
The format is a genuinely good fit for a language model, which is worth saying because most AI games are not. The host's job is narrow and well defined: understand an arbitrary question about a fixed scenario and answer it truthfully in one word. That is a task a model does well, and it removes the thing that always limited these puzzles, which is needing a second person who has read the solution and will not give it away.
The library is the other half. Over a thousand curated puzzles means the format survives past the four or five everyone already knows, which is where this usually stops being playable.
You choose a mystery from the library. Each is a short, deliberately incomplete scenario with an explanation you are trying to reconstruct.
You ask yes-or-no questions. The AI answers from the hidden solution, which is the whole mechanic, and it holds the constraint rather than drifting into telling you.
When you are stuck it offers soft hints, calibrated to nudge rather than solve. That is the part a human host usually gets wrong.
Play is metered in credits, with paid tiers adding bonus credits and a fast mode with roughly five-second responses, which matters more than it sounds in a game built on rapid back-and-forth questioning.
- •Over 1,000 curated puzzles - enough that the format does not exhaust itself.
- •AI host answering yes or no - holds the solution without leaking it, which is what the game needs.
- •Soft hints on request - graduated help rather than the answer.
- •Fast mode on paid tiers - about five-second responses, which suits the rapid questioning the format encourages.
- •Runs in the browser - nothing to install, no account needed to start.
- •Free to begin - credits govern how long you play rather than gating the format itself.
Anyone who liked these puzzles and ran out of them, which is the usual fate. Also groups: the format works read aloud with several people questioning, and the AI removes the need for one person to sit out knowing the answer.
Teachers and facilitators use situation puzzles for reasoning practice, and a thousand-puzzle library with a host that never spoils the answer is a better version of that than a printed list.
It is a game rather than a tool, and priced accordingly. The free entry is the right way to judge whether the AI holds the format well on the kind of question you naturally ask.
