Rootly gave up on small pull requests

Two years of enforcing stacked pull requests capped at a few hundred lines, and Rootly has dropped the rule. Their reasoning, via CTO Quentin Rousseau and written up by Matt Saunders: agents now produce whole features, and splitting a coherent feature into artificial slices makes it harder to review, not easier.

The line worth keeping is this one:

AI bugs are context bugs. The code works, but it is applied to the wrong thing.

That is the most economical statement of the problem I have read this year. The small-PR rule was never really about size. It was a proxy for reviewability, and it worked because a human writing three hundred lines had to understand them first. Take away that guarantee and the proxy stops measuring anything. You can read every line of a four-hundred-line diff, find nothing wrong with any of them, and still miss that the whole thing is solving a problem the system does not have.

So Rootly replaced size with blast radius: feature flags, progressive rollout, and the ability to undo. They also built an internal reviewer that assesses risk profile and conformance to standards rather than reading the diff the way you would read a colleague's.

I am half-convinced. Moving the safety boundary from review-time to runtime is a genuine answer to a real change, and "can we turn it off quickly" is a better question than "is it under three hundred lines". But it is also a quiet concession that the diff is no longer where the defect lives, and rollback only helps for failures loud enough to notice. The context bugs Rousseau is describing are frequently the quiet kind — right code, wrong assumption, no alarm.

Still: a team saying out loud that a practice they enforced for two years has stopped working is worth more than another vendor post about velocity.