Summary
Developer and creator Theo announces TSC RS, a complete rewrite of the TypeScript compiler, type checker and language server in Rust, built almost entirely by AI agents. The project took five months. About $400,000 in Codex tokens produced roughly 84% compatibility, while around $20,000 of Claude Opus 5.5 usage finished the job in two weeks, with no code read by hand.
The video covers the results. TSC RS is published on npm and runs about 12.5 times faster than TypeScript 6, the last JavaScript-based version, and roughly twice as fast as TSGO, the Go-based TypeScript 7 from Microsoft. Theo also compares it with Bun’s new bun check, which is faster in many cases but less faithful on large codebases such as tRPC, T3 Code and the Effect repository.
Beyond the benchmarks, the discussion covers why Theo took on a task once considered impossible, how the work was verified, what it means for software engineering when models can port entire compilers, and a vibe-coding demo that motivated the project. A sponsor segment on Qdrant’s vector search is included.
📺 Source: Theo – t3․gg · Published October 10, 2026
🏷️ Format: News Analysis
