ts-rust, an AI-written Rust port of tsc, passes all 181,711 tests
Theo Browne released an experimental, MIT-licensed Rust rewrite of the TypeScript 7 compiler, written almost entirely by Claude Opus 5.5 in two weeks.
Theo Browne, creator of the T3 stack, has published ts-rust (also called tsc-rs): an experimental, MIT-licensed Rust port of the TypeScript 7 compiler, type checker and language server, built as a drop-in replacement for tsc.
The port passes all 181,711 tests carried over from TypeScript’s own Go-based test suite, and the README reports identical diagnostics to the official compiler on real projects including TanStack Query and Hono. Browne says it type-checks about 1.61 times faster than tsc 7 on average, and 2.22 times faster on his own T3 Code project (7.25 seconds versus 16.10 seconds). The code was written almost entirely by Claude Opus 5.5, which produced a working version in around ten hours and a finished port in two weeks for roughly $24,000 in API spend, after an earlier attempt with other models burned through more than $400,000 without reaching usable compatibility. Browne states in the README that he has never read a line of the generated code.
npm i -g tsc-rs
tsc-rs --versionWhy it matters: if the benchmarks hold up outside Browne’s own tests, large TypeScript codebases get a faster alternative to the official Go compiler that claims to need no build config changes. It’s also a concrete data point on what an unsupervised coding agent can now produce: a full, passing compiler port, not a demo.
The caveat: it’s pinned to an early TypeScript 7.1 development revision, has known issues with memory growth in long editor sessions and monorepo edge cases, and no one, including its author, has reviewed the code by hand.