To look for weak spots, a learning program was set loose on the economy to find a way to cheat that pays. It was built with LeWorldModel, a tool from AI research that learns to predict what will happen next. Its first job found a real flaw: the test jobs could be told apart from real work by their timing. That was fixed, and afterwards the cheater lost money.
The learned red team was built around LeWorldModel, a world model from AI research (Maes, Le Lidec, Scieur, LeCun and Balestriero, 2026): a model that learns to predict the next state, here adapted to the economy's numbers, given a head that estimates earnings, and used to plan each move. Its first study asked whether planted cases could be told from real work. In the first implementation they could: 99% of plants reached their inspector one tick after delivery. That was corrected in the engine, with no rule moved; on the corrected construction the learned inspector did worse than a careful one.
The tool is LeWorldModel (a JEPA world model with SIGReg, planned by CEM) on stable-worldmodel
Source: HANDOFF.md l.2109
the world model (LeWM's recipe on the vector plus a wealth head) trained on each, a logistic probe for plant-vs-real on the latent, the raw observation, the context alone and the case's fields alone
Source: HANDOFF.md l.2201–2203
The probe found a tell the readers had the sign of wrong: on the first implementation the plant actor's submission ran inside the engine's tick step, after the driver's seating, so 99% of plants reached their reviewer with a seating gap of one tick (raw AUC 0.97, the gap alone 0.85)
Source: HANDOFF.md l.2206–2208
The learned reviewer is a no-win outside noise on the wrong side: −507 ± 143 at round 10
Source: HANDOFF.md l.2210–2211