crash-test
Oct 2026Can you trick an AI agent into paying a scammer?
Yes, often. Spending caps didn't save the money. An allowlist or Brake did.
The setup
Eleven scams taken from real 2026 incidents (poisoned memory, fake gateway errors, look-alike pages and addresses, fake refunds and a few more), each with an innocent twin, so honest payments the agent refused get counted too. They run against four kinds of wallet on a local chain. The chain decides what got stolen, not the model and not the person running it. The predictions were written down and frozen before the main run.
Results · Claude Haiku 4.5, 352 runs, pre-registered
- With a plain private key the agent got fooled in 27 of 44 attacks, and lost money every one of those times.
- Spending caps barely helped: 22 of 24 fooled runs still leaked.
- An allowlist, or Brake with a watcher, stopped all of it (0 of 44). The price: about 9% of honest payments didn't go through, vs 3% with the plain key.
- Side test across seven models (one seed only, so treat it as a hint): Claude Haiku 5.5, Claude Opus 4.5 and DeepSeek V4.1 Flash were never fooled. GPT-5 mini was fooled 61% of the time.
Solo project, not peer-reviewed. Claude Code was the implementation tool; the design and every decision were mine.