New Year's Eve 2025. A Claude Code sub-agent entered a loop, retried the same failing command over 300 times across 4.6 hours, and burned roughly 27 million tokens. The user got the bill. GitHub issue #15909 was closed without a fix.
From the orchestrator's vantage, everything looked fine. The agent was running. Running looks like progress when you haven't built anything that measures progress.
Nobody ships a circuit breaker before the first overnight run teaches them why they needed one.
