Experiment 001 · model jev-1.13.0
A city of a thousand people. Nobody scripted them.
One small AI model, Jev by TypeSafe, decides what every one of them does next. All thousand, about once a second, for a cent and a half. This page is a recording of it thinking. The city itself is live.
- 1,000
- minds a tick
- 0.98 s
- median, all of them
- $0.015
- per tick, measured
What one second buys
Code runs the world: time, hunger, fire, gossip, injury, death. Jev is a “System One” model: it supplies only judgment. It never writes a word and never sees a number, only plain phrases that code wrote: “starving”, “was robbed by Cora”, “wolves, right here”.
One mind, in full
This is everything Jev knew. This is what it said.
A real decision from the recording above, chosen by a rule, not by taste: the first person with danger on top of them about whom Jev was unsure.
Code rolls dice against those odds. Try it.
Twelve minds, one verdict
A thief is caught. The city decides.
Code seats twelve citizens, friends and rivals first. Jev judges each one once: would this person vote guilty? Visitors call the verdict before the votes turn over. This one really happened.
The number on each juror is the probability Jev gave a guilty vote; the vote is drawn from it. Gold: tied to the accused. Blue: tied to the victim. Tested before it was built, with pass marks committed in advance: what held and what failed.
Citizens of X
A thousand citizens. One owner each.
Sign in with X inside the city and the citizen you were given becomes yours alone. Owners score by calling what citizens do before it happens. This board is live.
- Loading the live board…
Failures first
None of these raised an error. All of them were wrong.
Confident, well-formed, wrong behaviour, visible only in what a whole population did. Each was found by replaying the exact moment and changing one field.
- 80 of 80
The frozen village
We told Jev what each villager was already doing. Every one of them chose it again, at 0.92 confidence.
- day 3
The chapel
We described what the crowd nearby was doing. 73 of 78 joined in. By day three the whole village was praying, starving.
- 34.6
The famine
Starving farmers answered “eat” when there was no food, never “farm”. That needs a “therefore”, and Jev takes one step. 34.6 of 80 died, per run, until code closed the gap.
- −0.03
The alibi
All that a witness for the defence moved a jury. Jev under-weights evidence of innocence, so the game does not rely on it.
The expensive one: villagers[37]
Jev cannot count, and an array index is a count. Past about the twentieth item in a list it answered, confidently, about nobody in particular. We had run a whole pre-registered evaluation that way. We re-ran it keyed by name and published both.
gap between greedy and loyal villagers, by position in the list
keyed by name by array index
Every dollar
$14.20 for all of it.
Seven rounds of evaluation against baselines, twenty benchmarks, and the live city: 17,713 requests, 338 million tokens, each one a line in a ledger. Our own waste is in it, on purpose.
Live, the city costs about $3.50 an hour whether one person is watching or ten thousand, and nothing when nobody is. Ledger as of 19 September 2026; the full table is in the study.
It is running right now.
You will be given one citizen the moment you arrive. Follow them. Call what they do. Claim them with X, and nobody else can: there are only a thousand.
Enter JevtownFree. No account needed. Works on a phone.
An experiment by elberacasa