https://macworks.dev/tags/bun/Recent content in Bun on MacWorksHugoenhttps://macworks.dev/docs/week/simonwillison/simonwillison-2026-07-19/Mon, 01 Jan 0001 00:00:00 +0000https://macworks.dev/docs/week/simonwillison/simonwillison-2026-07-19/<h1 id="simon-willison--2026-07-19">Simon Willison — 2026-07-19<a class="anchor" href="#simon-willison--2026-07-19">#</a></h1> <h2 id="highlight">Highlight<a class="anchor" href="#highlight">#</a></h2> <p>Simon&rsquo;s quick investigation into Claude Code&rsquo;s internals is a classic example of his &ldquo;poke at it and see&rdquo; ethos, successfully verifying that the new Rust port of Bun is quietly powering the popular AI CLI tool in production.</p> <h2 id="posts">Posts<a class="anchor" href="#posts">#</a></h2> <p><strong><a href="https://simonwillison.net/2026/Jul/19/claude-code-in-bun-in-rust/#atom-everything">Claude Code uses Bun written in Rust now</a></strong> Simon puts his sleuthing hat on to verify Jarred Sumner&rsquo;s claim that Claude Code is now running on a Rust port of Bun. By inspecting his own Claude Code installation, he found it running an unreleased Bun v1.4.0 and discovered hundreds of Rust source filenames. It&rsquo;s a neat bit of validation showing that this major architectural rewrite is already running reliably across millions of devices, proving that &ldquo;boring is good&rdquo;.</p>