6 Agent Patterns From Claude Code's Leaked Source

On March 31, Anthropic accidentally shipped Claude Code's full TypeScript source in an NPM package update. About 1,900 files. Gone public, then yanked — but not before the internet had it. Haseeb Qureshi published a detailed breakdown of what's actually in there. I went through it. Here is what stood out from a builder's perspective — not the drama, but the decisions. These are patterns from a system that runs millions of agentic sessions. The harness, not the model, is where the production expe