Claude Codeは現在Rustで書かれたBunを使用

Simon Willison’s Weblog Subscribe Sponsored by: Atlassian — Give your agents a plan. Not a prompt. New Jira capabilities unlock full-context for AI-native software development. Assign tasks to Claude, Cursor, or GitHub Copilot, now directly from Jira. Learn more 19th July 2026 In Rewriting Bun in Rust Jarred Sumner made the following claim: Claude Code v2.1.181 (released June 17th) and later use the Rust port of Bun. Startup got 10% faster on Linux but otherwise, barely anyone noticed. Boring is good. I decided to have a poke at my own Claude Code installation to see if I could find evidence that it was using Bun written in Rust. I found these two commands convincing: strings ~/.local/bin/claude | grep -m1 'Bun v1' For me this outputs Bun v1.4.0 (macOS arm64). The most recent release of Bun on GitHub is currently v1.3.14 from May 12th, so that v1.4.0 version number in Claude supports them shipping a preview of a not-yet-released Bun version. strings ~/.local/bin/claude | grep -Eo 'src/[[:alnum:]_./-]+\.rs' This outputs a list of 563 filenames, starting with these: src/runtime/bake/dev_server/mod.rs src/runtime/bake/production.rs src/bundler/bundle_v2.rs It looks like Bun in Rust is indeed being run in production across millions of different devices. Like Jarred said, "Boring is good". Posted 19th July 2026 at 3:54 am Recent articles Kimi K3, and what we can still learn from the pelican benchmark - 16th July 2026 The new GPT-5.6 family: Luna, Terra, Sol - 9th July 2026 sqlite-utils 4.0, now with database schema migrations - 7th July 2026 This is a note by Simon Willison, posted on 19th July 2026. rust 112 anthropic 311 claude-code 122 bun 7 jarred-sumner 3 Monthly briefing Sponsor me for $10/month and get a curated email digest of the month's most important LLM developments. Pay me to send you less! Sponsor & subscribe Disclosures Colophon © 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026