What a $900M Bank Error Teaches Us About AI Agents - John Feminella, Two Sigma

In 2020, Citibank accidentally sent about $900 million to Revlon’s lenders instead of an $8 million interest payment, even though the procedure, the warning pop-up and three approvers all did what they were supposed to. John Feminella, who works on AI architecture and engineering at Two Sigma, uses that story to show how to give AI agents real autonomy without locking everything down. He walks through five composable controls: an agent registry, risk-based review, tool access that follows an agent’s declared purpose, shared firm-wide evals, and classifiers that send humans only the approvals that matter. Views are his own, not Two Sigma’s. Chapters: 0:00 Intro 0:43 When controls fail 1:03 The $900M Revlon payment mistake 4:58 What this has to do with AI agents 5:22 Humans aren’t deterministic either 6:07 Approaches that don’t work 7:32 Control 1: An agent registry 9:47 Control 2: Risk-based review 11:47 Control 3: Tools follow purpose 14:42 Control 4: Shared evals 16:17 Control 5: Ending approval fatigue 18:07 Putting it all together 18:32 Why cars have brakes John Feminella https://www.twosigma.com Join us in SF for the second annual AIE CODE summit: https://aie.codes our last flagship summit of 2026. Applications live now!