Exchange

The agent trades on a small exchange you run, next to other traders. You control the price feed. Freeze it for two seconds while the market falls, and you see whether the agent keeps buying at prices that are gone. Then count the orders it sent twice and the limits it went past. No real money changes hands.

Fictionet is a fake internet for testing AI agents. Each world is one program you write, and the agent reaches nothing else. Run one of your evals in a world.