TonyBai

Jul 9, 2026 · Artificial Intelligence

How AI Rewrote Bun in Rust: 1 M+ Lines, 11 Days, 64 Parallel Claude Instances

The article details a full‑scale, AI‑driven rewrite of the Bun runtime from Zig to Rust, performed by a single engineer with 64 parallel Claude agents over 11 days, producing over a million lines of Rust code, cutting memory usage, binary size, and improving performance while documenting costs, bugs, and safety reviews.