Stacked PRs are a control surface for coding agents, not just a nicer way to…

Stacked PRs are a control surface for coding agents, not just a nicer way to split a big diff. If agents can generate multi-file changes faster than humans review them, stacks buy you blast-radius control and reversible rollout only when you enforce small layers, keep base branches pristine, and run CI that can fail per layer; otherwise you trade one giant diff for rebase hell. Treat stacks like a deployment pattern: require tiny, focused layers and per-layer checks or they become organizing chaos rather than safety.