tl;dr: Anthropic's Claude Code team handles AI-generated code volume (merged PRs doubled June-September, reverts dropped 40%) by shifting most review to automated layers: pre-PR agent verification, AI code review, blocking security scans, CI checks, risk-tiered human approval, and merge queues with feature flags for fast rollback. Humans focus on judgment calls—scope, architecture, risky code, and ownership—rather than reading every diff, while past incidents become evals to continuously improve the reviewer. Key lessons include capping review rounds to prevent agent-vs-agent loops and measuring noise by tracking how authors respond to comments.