How Claude Code Is Used in Practice: 80% of Anthropic's Production Code Is Now AI-Authored

My take: Anthropic published an internal analysis today on how Claude Code is used in practice: its engineers now ship eight times as much code per quarter as they did in 2024, and 80% of the code merged into production is authored by Claude. The study analyzed nearly 400,000 real sessions from October 2025 through April 2026.

The most revealing finding is about collaboration: in a typical session, the human makes most of the planning decisions (what to do) and Claude makes most of the execution decisions (how to do it). And the more domain expertise a person brings, the more work Claude does per instruction received.

I use Claude Code every day to build WandaBuilds, and what this research describes matches exactly what I experience: AI does not replace you, it gives you scale. The real question is what you choose to do with that extra capacity.