# bun

Jarred Sumner rewrote 535K lines of Zig into Rust with 64 Claude agents in parallel, adversarial code review, and mechanical porting. 11 days later: all tests green, memory leaks fixed, binary 20% smaller.

Mitchell Hashimoto's point about Bun moving from Zig to Rust is not that Rust won and Zig lost. The more useful lesson is that programming languages are becoming more replaceable, and developer-tool companies need to manage technical narratives before the internet turns them into faction wars.

The author spent a week tearing apart Claude Code's 213MB binary and discovered it's essentially a massive prompt delivery system built on Bun, packed with unreleased features and telemetry.