Bun creator says he rewrote Bun from Zig to Rust using a pre-release version of Claude Fable 5 in 11 days; the task would've taken three engineers about a year (Jarred Sumner/bun.com)

Techmeme ·

Bun’s creator says a pre-release Claude Fable 5 completed a major runtime rewrite, signaling stronger long-horizon coding capability.

Categories: Model Releases

Excerpt

<a href="https://bun.com/blog/bun-in-rust"><img align="RIGHT" border="0" hspace="4" src="http://www.techmeme.com/260709/i24.jpg" vspace="4" /></a> <p><a href="https://www.techmeme.com/260709/p24#a260709p24" title="Techmeme permalink"><img height="12" src="http://www.techmeme.com/img/pml.png" style="border: none; padding: 0; margin: 0;" width="11" /></a> Jarred Sumner / <a href="https://bun.com/">bun.com</a>:<br /> <span style="font-size: 1.3em;"><b><a href="https://bun.com/blog/bun-in-rust">Bun creator says he rewrote Bun from Zig to Rust using a pre-release version of Claude Fable 5 in 11 days; the task would've taken three engineers about a year</a></b></span>&nbsp; &mdash;&nbsp; Disclosure: Bun was acquired by Anthropic in December 2025.&nbsp; I and others on the Bun team work at Anthropic.</p>