One deprecated flag reused in 2012 cost Knight Capital ~$440M in 45 minutes.

They repurposed an old “Power Peg” flag for a new feature. The ancient code was never fully removed, a bad deployment left one server on the old version → millions of erroneous orders, billions in unintended positions, near-bankruptcy.

One tiny flag + tech debt = financial disaster.

Now picture the future: AI-generated code slop becomes the majority. Thousands of inconsistent, barely-tested snippets, forgotten patterns, hidden bugs — all piling up at hyperspeed.

If one flag almost killed a trading giant, what happens when the codebase is mostly AI garbage?

Ruthless testing isn’t a nice-to-have anymore, it’s survival.

Full story: https://specbranch.com/posts/knight-capital/