How Worlds differs
Stateful copies of business systems are not unique to us; hosted platforms sell them, metered per run. What that category does not claim and Worlds does, with something published behind every line. Checked against their public sites on 2026-09-08. Tell us what changed and we will update it.
| Capability | Hosted, metered twin platforms | Worlds |
|---|---|---|
| Checked against the real API | Fidelity asserted, no record published | A probe battery runs against real Stripe on a schedule, dated and published. |
| Deterministic, replayable | Not claimed | The same seed and script give byte identical worlds. Every failure replays. |
| Failure injection, time travel | Not claimed | Eight failure scenarios and a clock you can advance through renewals, prorations and period end cancellations. |
| Your own account as the world | Not claimed | Import your own account, pseudonymized, and commit it. |
| Where it runs | Hosted; your own environment on an enterprise tier | Your laptop or your CI. |
| Pricing | Metered by the run, the minute or the CI check | Flat price, unlimited runs. |
| What a verdict is | Judging criteria over traces; forbidden effects | Dollars wrong from the world diff, a verdict and a diagnosis per task, and a policy judge that only cites amounts it can see. |
Eval platforms (Braintrust, Langfuse, Arize, Confident AI) grade what the agent said, from traces. The system it acts on is yours to supply. Keep your traces where they are and take the environment and the verdict from Worlds.
Conversation simulators (Coval, Hamming) simulate the customer talking to your agent. Worlds simulates the systems your agent acts on. The other half of the problem.
Environment vendors for labs (Fleet AI, Halluminate) sell environments in which computer use agents are trained. A different buyer and a different product.