Zig Creator Calls Spade a Spade, Anthropic Blows Smoke

Zig Creator Calls Spade a Spade, Anthropic Blows Smoke

I harass the sea with my tiny boat and am called a pirate, you do it with a great fleet and are called a king.

Anthropic is actively campaigning to end software engineering. They need you to believe they can do that. Well, maybe it’s not you that they need to convince. Maybe it’s your C-Suite, various world leaders, or the manager of your retirement fund. They’ve raised $132 billion in investment, and are approaching an IPO valued over $1 trillion. Since they cannot show profitability, this depends on selling their hypothetical future impact.

In literary terms, Anthropic is an unreliable narrator.

One of their key narratives is: Coding is going away, then the rest of software engineering, and eventually most other human labor. This kind of money behind this kind of story has an impact, regardless of how true we think the story is.

People will make architecture, product, and staffing decisions based on these events. Many of those decisions will be based on fear - fear of layoffs, rapture-esk warnings of being “Left Behind”, Doom Trolling, etc…

To make good decisions we need to think clearly, which is hard right now. Put on your skeptical hat.

Views are my own. I have no history with Zig. I’ve never spoken to Andrew Kelley, but found his recent JetBrains interview a great watch.

My interest here is in public literacy about AI in software. That’s been my career focus now for 3 years, along with improving the technology itself. During half of that time I was Chief Architect of a coding agent startup - both a customer of Anthropic’s models and competitor to their agent Claude Code. My current project is The Coding Agency.

So where were we?

This week, Anthropic / Bun put out their explanation of the decision to port Bun from Zig to Rust. This explanation came two months after merging the migration to the mainline. Explaining the direction beforehand would have been more traditional in an infrastructure project like this, but meanwhile the delay conveniently allowed the story to be carried by sexy headlines like The Register’s Anthropic’s Bun Rust rewrite merged at speed of AI. Much invest. Very wow.

Zig’s creator Andrew Kelley has now put out a response with his own thoughts. It’s blunt, to an unusual degree. That has questionable optics. As a general rule, you would not want to worry that when you switch programming languages you will wake up the next morning to the old language’s leader unloading on your personal flaws. As Dax hilariously put it:

guys we have a pretty substantial opensource zig codebase and i’m terrified he’s gonna look at it

Still, as I read Andrew’s piece I found myself cheering out loud. I may have briefly jumped around the room. Some called his take a “meltdown”, all I can say is he’s gained a new fan today.

Sometimes things need to be called out.

What is model behavior?

On my best days I’d aspire to something like Buddhist right speech, a high standard that everything we say should meet all five of these criteria.

• Is it true?
• Is it helpful?
• Is it timely?
• Is it kind?
• Is it from kindness?

We’re breaking decorum a little, straying into “true, but unkind” territory. I’m defending someone’s choice to do that. I don’t do that lightly, and I hope it’s helpful.

Background

Just to catch you up…

• Bun is a TypeScript runtime, like a faster NodeJS.
• Zig is a systems programming language, like a modern C.
• Bun was written in Zig until recently - one of the largest Zig codebases.
• Bun claims near 100% AI contributions.
• Zig allows 0% AI contributions.
• Bun was acquired by Anthropic, a leading AI model lab.
• Bun’s founder experimented with a massive agentic rewrite from Zig to unsafe Rust.
• That experiment was merged days later and is now the official version.

This is situation is controversial on a few fronts, though apparently no one involved actually wants Bun to stay in Zig. The drama lives purely in the meta-discussion. The migration process itself is pretty interesting, I would consider doing something similar in the right situation.

Who to believe

When people choose between Zig and Rust for their projects, they will naturally see the Bun situation as a data-point. That fact that one of the biggest Zig users wound up reversing the decision feels relevant, regardless of the reasons. People will try to understand what happened, and decide which is more true:

Anthropic/Bun story: Bun tried everything reasonable, and was still overwhelmed by memory bugs because Zig wasn’t up to the task.

Andrew’s story: The Bun code is a mess because of their engineering decisions, including overusing AI agents to write and review everything.

I’d lean more toward the latter, but I suspect the dominant factor is more boring:

Ray’s story: Faced with a legitimate challenge of memory bugs, there were several viable options. Management eagerly approved the Rust rewrite option because it was a great marketing opportunity to showcase their new Fable model, Anthropic already uses Rust, and Zig is openly against using Anthropic’s products.

That makes fine business sense, it just isn’t a marketing story. The marketing needed to focus on how their AI was powerful enough to do this rewrite (even though it was not powerful enough to catch a use-after-free).

For better or worse, this baggage is now top-of-mind in the Rust vs Zig question. The situation tends to pit Jarred’s judgement against Andrew’s in the eye’s of the community. Any face-saving exaggeration spoken through Anthropic’s megaphone could unintentionally affect Zig’s reputation.

I can understand why rather than leave well enough alone, Andrew would decide to… add some context.

Is this a smear?

From my perspective, Anthropic is the party we need to hold accountable here. That’s what this is all about. Bun founder Jarred Sumner is getting caught in the crossfire in a sense. So is Zig.

It would be nice if this could be discussed strictly on the technical points, and we’ll get to them. However, I don’t think Anthropic is making a technical argument, they are dealing in spectacle.

Anthropic is using Jarred’s credibility to help sell their narrative. In responding to that, we’re commenting on his credibility. That’s messy. I don’t love it.

Still, if reporting the things that someone says and does comes off as a smear, then maybe that behavior was part of the problem too.

The meat grinder

My first impression of the Bun project was the 2022 announcement, including this warning to recruits.

Oven is going to be a grind, especially the first nine months or so. If work-life balance means a lot of time spent not working, it’s probably not a good fit.

When I see a statement like that from a prospective manager, it says a number of things, not the least of which is “this person has no idea what they are doing”. A lot of reasonably good coders have never seen an example of a good manager, and have all kinds of weird ideas about what management is.

Running at “crunch time” all the time is bad for health and bad for productivity. That is a robustly established fact about knowledge work. For some references, see the Human Factors section of Hillel’s Empirical Software Engineering.

My advice? Don’t work for people that brag about 90 hour weeks. Work for people who will defend your ability to sleep at night.

In Andrew’s piece, he summarizes what he’s heard from the grapevine of the Bun team’s experience:

Poor communication, unrealistic expectations, low empathy, no experience. Just a total shit show

I mean… of course it was. The hearsay is essentially repeating what was announced publicly. Their job listing might as well have said, “now seeking applicants for total shit show”. It’s bad form for us to say this out loud. We’re supposed to let the Tech Bros go on about how cutting corners is some genius productivity hack. Then the people that listen to them can eventually call us in to