We're on Call for Code Nobody Wrote
LeadDev, Wednesday, September 9th, 2026
Runtime behavior is the only truth when the person paged never wrote, and may never have read, the failing code.
On-call has a new shape when a large share of production code was generated rather than authored.
The engineer paged at 3am may have reviewed the change but has no mental model built from writing it, so the usual debugging shortcut of remembering intent is unavailable.
The article's conclusion is that runtime behavior becomes the only reliable truth, which raises the value of observability, structured logging and reproducible environments relative to code familiarity. It also raises uncomfortable questions about what review was actually verifying.