July 27, 2026
Rust in peace, hype cycle
How is the Bun Rewrite in Rust going?
Bun’s big AI makeover is sparking side-eyes, snark, and a very loud "uh, really?"
TLDR: Bun’s AI-assisted rewrite was sold as a fast, expensive breakthrough, but critics say the real story is the backlog, delays, and cleanup still hanging around weeks later. In the comments, people are split between "this was overhyped" and "it’s finished, just messy" — which matters because it’s becoming a test case for whether AI coding claims match reality.
What was pitched as a shiny 11-day, $165,000 AI-powered rewrite of Bun, a popular developer tool, has turned into a full-on comment-section cage match. In his post, Tom Lockwood basically says: hold the applause. Yes, Bun says it was rewritten from one programming language into another with help from Anthropic’s AI, but weeks later there’s still no new public release, and the pile of open robot-made pull requests has exploded. Translation for non-programmers: the flashy "we did it" announcement may have arrived long before the cleanup crew did.
And the community? Absolutely not calm. One camp is doing the classic tech-world eye roll. The top mood is basically, if you’ve ever worked at a startup, you already know how this movie ends. Others say the hype was wildly premature, accusing AI boosters of declaring victory because the demo looked good before anyone checked the mess backstage. The sharpest criticism is about cost: commenters argue that comparing $165k in AI bills to a team of human engineers misses the point if the result still needs mountains of fixing to look clean and polished.
But not everyone is ready to call it a flop. Some defenders say the rewrite is, technically, done — it’s just buried under old problems and post-launch cleanup. Even the author popped into the comments with a graph correction, which only added to the vibe of live-public-forensics. The overall energy is half detective story, half roast session, with a side of "AI ate the homework and now everyone’s checking the receipts."
Key Points
- •Tom Lockwood analyzes Jarred Sumner’s July 8, 2026 claim that Bun was rewritten in Rust over 11 days at a reported cost of $165,000 in Anthropic API calls.
- •The article states that the reported API cost implies roughly $15,000 per day and argues that this figure appears not to include ongoing CI/CD costs on Buildkite.
- •Lockwood reports that as of July 27, 2026, Bun had no new release tag after the rewrite was merged to main, with the latest tag still bun-v1.3.14 from May 12, 2026.
- •He says open pull requests from robobun increased from 1,277 on July 9 to 2,475 on July 27, using robobun as a proxy for Claude-generated PRs.
- •Based on observed Buildkite merge times of roughly 40 to 90 minutes, the article estimates that merging all open Claude-related PRs continuously would require about 86 days of pipeline time.