A refund bug, a four-minute fix
How a support team at Halcyon found the prompt that broke refunds, and what it replaced.
T
Ines Carvalho
5 min
Halcyon's support agent started refusing valid refunds on a Tuesday. The first report came from a customer, not from a dashboard.
Four minutes
The team opened the failing run, saw the eval case refund-edge-12 at 0.41, and opened the prompt diff from the previous version. The change was a single sentence about policy limits.
The fix
They rolled back, rewrote the sentence, added two cases and shipped the next version through the gate.
