Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Claude Code uses Bun written in Rust now

simonwillison.net

Post reply on HN
Print view View original

351–360 of 920 posts

Re: Claude Code uses Bun written in Rust now

#351

Post by jm4 »

weakfish wrote: post #249
johnfn wrote: post #233

Earlier quoted context omitted.

Why would rewriting Claude code, an app which probably has 30-40 (I might be significantly underestimating) extremely active contributors be easier than rewriting Bun, which has fewer contributors and almost certainly also less lines of code?

Because I’ve been told that Fable can do anything :-) My question is moreso “why was it ever JS in the first place” & the cost of a native rewrite would be cheaper than acquiring Bun no matter how you shake it

Probably because it consumes the same APIs originally developed for a web app and the same front end engineers likely created Claude Code. People assume Anthropic set out to create Code as a product and went through a normal design phase. I think it’s more likely it started as an internal tool or someone’s side project and blew up as a product when they released it to the public.

Re: Claude Code uses Bun written in Rust now

#352

Post by nerdix »

Aeveus wrote: post #175

Anecdotal, but I’ve been getting segfaults in Claude Code. I run inside Kitty tabs, and the entire tab becomes unusable when this happens. No response to inputs at all from that point. When this happens, a link shows up to report the issue. It’s not clickable (likely due to the segfault), and perhaps more important: it’s encoded, so you can’t see what you would be sending in your report. Hope it gets better.

I run Ghostty and Claude Code on a work macbook and I haven't seen this yet.

I actually used to have issues with run away memory leaks causing my computer to hang which often required a reboot to recover from. I haven't experienced that in a couple of weeks now. Too early to say just yet but I think its definitely possible that the rust port fixed a bunch of memory leaks that have tangibly improved the experience atleast for me.

Re: Claude Code uses Bun written in Rust now

#353

Post by harrisonjackson »

coldtea wrote: post #295
switz wrote: post #236

Earlier quoted context omitted.

It largely works and it's a massive business success. This is the classic engineer asking the 'why this technology?' to what amounts to a business question. They chose it early on, it works, and it makes obscene amounts of revenue. End of story. That doesn't mean it was the "greatest" choice, or has a perfect technical architecture. Rewrites are never easy, even the bun rewrite. But a non-UI developer tool with a rig…

> It largely works and it's a massive business success. This is the classic engineer asking the 'why this technology?' to what amounts to a business question. Your counter argument would be valid for a 2000 or a 2020 business decision about some tech stack. But the whole point of their product is that it supposedly nullifies such "business" concerns around the use of technology, by making it cheap and fast to build w…

By the same argument, why does it matter from the technology stack side? It doesn't just nullify the business concerns - it largely nullifies the tech stack concerns. Your preference doesn't matter if you aren't touching the code and the product works for your user base.

Re: Claude Code uses Bun written in Rust now

#354

Post by solumunus »

nozzlegear wrote: post #300
anamexis wrote: post #276

Earlier quoted context omitted.

What do you mean in spite of their tech choices? When have the tech choices ever been an issue in the lifespan of Claude Code? From where I sit, it seems like their tech choices enabled them to create an industry-defining product.

> When have the tech choices ever been an issue in the lifespan of Claude Code? This is just blatantly ignoring all of the glaring issues Claude Code has had over its lifespan.

I think the point is that people still continued to use it above everything else regardless.

Re: Claude Code uses Bun written in Rust now

#355

Post by larodi »

Ok, so let me wrap this for everyone:

While everyone here in this forum kept arguing (and fighting and yelling at each other) whether tis moral/right/secure/cheap for ppl to rewrite and ship a major software package with LLMs/agents, one of the main drivers behind AI actually did it, without consulting your opinion, and most same everyone actually slurped this decision without paying a a notice.

Boring is good, but this boring is super massive major thing that happened, and precisely because security is still intact.

Re: Claude Code uses Bun written in Rust now

#356

Post by hyperpape »

pdimitar wrote: post #342
coldtea wrote: post #295

Earlier quoted context omitted.

> It largely works and it's a massive business success. This is the classic engineer asking the 'why this technology?' to what amounts to a business question. Your counter argument would be valid for a 2000 or a 2020 business decision about some tech stack. But the whole point of their product is that it supposedly nullifies such "business" concerns around the use of technology, by making it cheap and fast to build w…

> But the whole point of their product is that it supposedly nullifies such "business" concerns around the use of technology, by making it cheap and fast to build whatever you like automatically. This is a spectrum, it's not just 0% vs 100%. Even Fable frakked up a few things really badly in my professional work (though to its credit after a very detailed 2h chat it self-corrected and fixed all the blunders). I would…

> $168k

Billions of dollars of annual revenue go through Claude Code, and the people who work on it must be a lot of millions in headcount.

The time matters a fair bit, it's probably time someone can't spend breaking things in the name of new features, but if rewriting the stack had even a tiny impact on retention or driving higher usage, it would pay back that $168k.

Re: Claude Code uses Bun written in Rust now

#357

Post by yojo »

switz wrote: post #236
weakfish wrote: post #212

Maybe I’m taking crazy pills, but I’m still stuck on “why the hell does a TUI need to run in terminal React by way of JavaScript” The fact that Anthropic felt the need to buy a runtime so they could make their TUI better speaks more to the quality of engineering than anything else IMO. If rewrites are so easy, why not rewrite CC in a native language? Would’ve been a hell of a lot cheaper.

It largely works and it's a massive business success. This is the classic engineer asking the 'why this technology?' to what amounts to a business question. They chose it early on, it works, and it makes obscene amounts of revenue. End of story. That doesn't mean it was the "greatest" choice, or has a perfect technical architecture. Rewrites are never easy, even the bun rewrite. But a non-UI developer tool with a rig…

I have been working all day every day in Claude. I loathe their bug-ridden UI. Every release is a new crop of bugs, sometimes the old ones get fixed, usually not.

Any kind of scrolling back, copying text, using their menu system - basically anything that isn’t typing characters has had/still has unaddressed bugs.

OpenAI shipped a competitive model and I’m over in Codex now. I have yet to hit a bug.

If you’re holding the SOTA crown, people will put up with your buggy mess. As soon as that crown slips your pile of trash becomes a huge liability.

Re: Claude Code uses Bun written in Rust now

#358

Post by endospore »

daishi55 wrote: post #335
endospore wrote: post #208

Earlier quoted context omitted.

> next step is to make it idiomatic rust You can tell what will happen when they release it before sorting out all the new bugs introduced by the not-exactly-line-by-line port.

Sorry you think they’re not going to continue developing and improving bun and making it more idiomatic? Given the success of the port so far and the fact that CC is now running on rust Bun, that seems highly unlikely to me.

That's a stated goal, so nope. But releasing it before any cleanups is another story.

I'd also like to inform you that

- the current success metrics solely consist of their advertisement, my eyes looking at the code strongly suggest otherwise

- the Bun team lacks knowledge to actually make it more idiomatic: none of the Bun team has written any Rust and relying on model knowledge is already proven insufficient.

The release decision itself is presumably driven by that tbh. It's only LGTM from there when nobody knows how to review unsafe Rust.

Re: Claude Code uses Bun written in Rust now

#360

Post by yojo »

yojo wrote: post #357
switz wrote: post #236

Earlier quoted context omitted.

It largely works and it's a massive business success. This is the classic engineer asking the 'why this technology?' to what amounts to a business question. They chose it early on, it works, and it makes obscene amounts of revenue. End of story. That doesn't mean it was the "greatest" choice, or has a perfect technical architecture. Rewrites are never easy, even the bun rewrite. But a non-UI developer tool with a rig…

I have been working all day every day in Claude. I loathe their bug-ridden UI. Every release is a new crop of bugs, sometimes the old ones get fixed, usually not. Any kind of scrolling back, copying text, using their menu system - basically anything that isn’t typing characters has had/still has unaddressed bugs. OpenAI shipped a competitive model and I’m over in Codex now. I have yet to hit a bug. If you’re holding…

Oh, and the memory use! I run a lot of concurrent sessions. 3 gigs for a terminal window is ludicrous.
Post reply on HN