40 cents a day, three weeks of corrupted writes, zero alerts fired

The cron had been running for three weeks when they noticed it. Forty cents a day. Nothing in the cost dashboard looked wrong — spend was flat, well below any alert threshold. What the dashboard couldn't see: the cron had been corrupting writes the whole time. The cleanup took longer than three weeks. The cleanup cost more than the compute bill ever would have. That's not a budget problem. The money wasn't the damage. The damage was invisible because the tooling could only answer one question —