Stephen Toub ports GitHub Copilot runtime to Rust

Microsoft Distinguished Engineer Stephen Toub discusses why and how he rewrote the 400,000-line GitHub Copilot runtime from TypeScript into Rust by himself. In an interview, Toub explains that the migration was motivated by the need for better embeddability, lower resource usage, and higher throughput as AI agentic loops evolved, choosing an incremental replacement strategy over a complete system rewrite. Open article →