An AI rewrote a million lines of code in 11 days.
This was a real production runtime. Bun, the JavaScript engine that millions of apps quietly run on, went from 535,000 lines of code in one language to more than a million lines in another, all of it inside two weeks. Close to a year of work for a team, by hand.
And the thing that rewrite produced is already on your PC. Not in a repo you would have to go dig up, not behind a signup. Ten seconds to prove it:
strings ~/.local/bin/claude | grep -m1 'Bun v1'
# → Bun v1.4.0
The runtime that million-line rewrite produced is already inside the tool you code with.
What pulled it off was the shape of the work itself. The models were ordinary, the ones you already run. Wire them as a graph instead of a line, and one job at a time becomes a fleet running at once.
That is the layer almost nobody is taught to see.
Most people still line their agents up and wait. You type a request, wait for it, fix what came back, then ask the next thing.