Claude Code v2.1.181 Ships with Bun Runtime Version 1.4 Rust Port | Tool Update
Anthropic acquired Bun on December 3, 2025. Claude Code v2.1.181, released June 17 2026, ships with Bun runtime version 1.4 which is the Rust port of Bun.
Published on MyPrivateClaw
Jul 20, 2026, 7:58 AM UTC
Coverage date
Jul 19, 2026
Last updated
Jul 22, 2026, 11:52 PM UTC
News summary
Claude Code v2.1.181, released June 17 2026, ships with Bun runtime version 1.4 which is the Rust port of Bun. Jarred Sumner rewrote Bun from Zig to Rust in 11 days using Anthropic's Claude Code and a pre release version of Claude Fable 5, achieving 100% of the test suite passing on all platforms. Claude Code v2.1.181 using the Rust port of Bun showed a 10% faster startup on Linux (from 517ms in v2.1.179 to 464ms) per production telemetry. Anthropic acquired Bun on December 3, 2025. Claude Code reached $1 billion in run rate revenue in November 2025. Bun v1.4.0 (the first version written in Rust) is available as a canary build via bun upgrade canary.