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Translating a project that includes a good test suite from one language to another is known to be a great case where LLMs work well.

When you’re starting with a complete codebase to use as an example and a test suite to check everything it’s much easier to iterate toward the desired goal. The LLM can already see what the goals are and how they’ve been implemented once already, which is a much easier problem than starting from a spec.

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Great case where rust works well too. I won't cite every famous libs that got rewritten in rust but it wasn't all with LLM.
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I fail to think of a successful Rust rewrite, so far what I've seen is just programmers who aren't sufficiently experienced, who decide to pick Rust and rewrite something in it, and then (this is the bad part) claim it's better for that reason only. It never is. It's always worse, because rewrites fundamentally end up with a worse product first.
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It's not hard to imagine a future where the only things committed to git repos are tests and specs.
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And maybe not even the tests. Just a specification for the tests.
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I can see open source projects as just prompts as well.
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The goal posts are always moving. This would have been an unthinkable task a couple years ago.
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Even last year at this time people wouldn't believe it.
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It's a new era of capital, literally, in software development. Ownership of the means of production is now concentrated.
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You could have said the same thing about steam power or electricity. And it’s not just an analogy: The magic of these things is in being universal information engines. You spend capital to build them, using well-understood, scalable techniques, plug them into electricity, and out comes value.

My point is, there’s no chance of a “haves and have nots” emerging, any more than electricity turned out that way in the modern world.

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Electricity might be a good analogy - but for the other side of this argument.

In the US, (nearly) full electrification wasn't achieved until the late 1940's/early 1950's - a process of nearly a century. (A moment of personal trivia, my great grandfather worked on crews electrifying rural areas of the midwest.)

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We already have SOTA local inference devices in everyone’s pocket, which also provide high bandwidth access to SOTA data center inference at what is rapidly becoming commodity pricing.

What comparable gap is there to bridge?

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>My point is, there’s no chance of a “haves and have nots” emerging, any more than electricity turned out that way in the modern world.

Energy costs vary widely across the world and that has enormous capacity for the economies of different countries and their industrial capacity.

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https://worldpopulationreview.com/country-rankings/cost-of-e...

Electricity looks pretty even. Higher in Europe but they can afford that.

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Due to purchasing power parity, it is actually much hhigher in poorer countries, in that they are absolutely still asking the have nots.
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When something is expensive specifically because a country is poor and everything is harder to buy, that expense isn't making inequality worse.
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I am talking about have nots at a nation scale here. At level of British empire.
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I'm not sure what that means. Every country has electricity and any country can get GPUs if it wants them.

(And the profit from selling GPUs isn't haves versus have nots, it's a couple companies versus the entire world.)

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Unclear. Very good products tend to be about doing one or a few things very well; not about doing tons of stuff. So far, all I see is “Man, Im a 10x engineer now!”, shipping more code but without clear direction and taste. At this point, most of LLM-based work is just noise.
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There are not many companies that live off taking full test suite made over decades and just generating code off it.
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Nah. These agents are getting easier and easier to run local. Have you tried Qwen 3.6 27b? It’s insane what it can do compared to its size. Like 100% vibe small projects if you manage context properly.

These models are a race to the bottom just like compute.

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I don’t think it matters. Local matters becoming better has not stopped demand for SOTA models.
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I can't help but wonder what this cost in USD assuming you paid standard rates from Anthropic. Can someone even ballpark the price?
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Much less than what it’d costs for a team of rust engineers.

This is both amazing and scary; has been for a while now.

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It costs several times what it would cost a small team of engineers, even assuming you gave the engineers more time to do it. I'm guessing (wildly) this was around 0.5M USD in compute time. You do get the result quicker, though.
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> I'm guessing (wildly) this was around 0.5M USD in compute time.

That seems like an especially wild guess. If you take e.g. Opus 4.7 prices, and make the assumption that you are consuming roughly $30 for every million tokens of output (this comes from just summing the $25 per million tokens of output and $5 per million tokens of input and assuming that caching basically makes all that work out), and assume an output rate of 80 tokens per second (which seems like a high estimate based on online searching), it would take you about 2411 days of non-stop Opus 4.7 usage to hit 500k in API spend.

The only way you could possibly run that amount of usage in 6 days is if you were running ~400 instances in parallel. From personal experience, that seems crazy high for this project.

I think you are off by at least an order of magnitude (potentially even 2 depending on how the person is managing agents, but I could see something like dozens of agents 24/7, so I'm way less confident in 2, but I think it's still more likely to be closer to 10-20k in API spend).

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Half a million is pretty damn cheap for a full rewrite into Rust of a million line of code codebase.
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But usually companies are much more careful before even spending that half a million. (And most companies don't have that money sitting around.) They would do small PoCs, do comprehensive benchmarks and evaluations of those PoCs, and decide whether to actually go ahead, and, more importantly, stick to it.

Being able to afford half a million doesn't mean you do it on a whim, or just throw all of that away if things don't go well.

But what do I know. I am nothing compared to our AI overlords like Anthropic.

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> They would do small PoCs, do comprehensive benchmarks and evaluations of those PoCs, and decide whether to actually go ahead

Perfect, $1mil in salaries to spare the company $500k in spend :)

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10k lines ~$250 in OpenAI API calls (no plan)

45 million lines would get to ~$1.125 mil for the linux kernel.

950k lines for Bun would get to $23,750

use whatever math you like ofc.

Does an Anthropic/employee pay that, no. Even if it's at a loss in terms of company revenue, it's worth burning the private capital for all kinds of other reasons.

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With less employees....
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Isn’t just one guy?
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Exactly
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This is exactly how Anthropic will market this rewrite towards companies thinking about doing more layoffs.

1 person did a rust rewrite that took 6 days that would have taken hundreds of engineers more than a year to do.

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> 1 person did a rust rewrite that took 6 days that would have taken hundreds of engineers more than a year to do.

The entire bun team was only about a dozen people and they wrote it from scratch.

It would not take hundreds of engineers to port the existing codebase to another language.

I think this is a cool experiment, but some of these claims are getting absurd.

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The saving grace here is a rewrite of a project with a good test suite is the sweet spot: LLMs are great at translation and do great with verifiable goals.

I agree it’s still mind blowing compared to before times, though.

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> would have taken hundreds of engineers more than a year

This is estimating what, 10 lines per day each? No way translating code is anywhere near that slow.

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It probably wouldn't take a single person who knew what they were doing more than a year to re-implement Bun in basically anything, by hand and from scratch, i.e. not even looking at source. Writing the code for something you already understand and have built before is incredibly fast.

I'm sure they'll market what you said, but it's so ridiculous that I would hope people would see through this stuff.

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And he has zero idea how it works. His capacity for understanding it is tied to his wallet now.
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It's actually tied to his employment at Anthropic.
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> 1 person did a rust rewrite that took 6 days that would have taken hundreds of engineers more than a year to do.

Even cheaper would just be to not do it in the first place. Was there a pressing need to rewrite it?

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The majority of Bun was written by one guy in less than a year. In what world would a rewrite take hundreds of engineers more than a year to do? The hyperbole is getting ridiculous.
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