Zig president says AI coding contributions are ‘invariably garbage,’ so he banned them

• Zig, an open-source programming language, bans contributors from using AI to code, edit, or debug.
• Zig president Andrew Kelley said that the AI-generated contributions have “no value whatsoever.”
• “They have negative value, because they take review time away from the team,” Kelley said.

Zig has put its foot down: No AI code allowed.

The open-source programming language is maintained by a 501(c)(3) and a network of contributors. Any programmer can submit code to its repository — so long as they follow a code of conduct.

One of Zig’s rules bans the submission of AI-assisted code. The policy is clear: They will accept no LLM-generated content, nothing paraphrased from an LLM, and nothing edited, brainstormed, or debugged by an LLM. In short: Keep AI out of it.

On the JetBrains podcast, Zig President Andrew Kelley called AI-assisted contributions “invariably garbage.”

“People are sending us contributions that have no value whatsoever,” Kelley said. “They have negative value, because they take review time away from the team.”

Code contributions are reviewed by a handful of core team members. That’s the “bottleneck,” as Kelley puts it: There are more pull requests than reviewers. At the time of the recording, Kelley said that Zig had 200 open pull requests.

Those AI-generated “slop contributions” slow the whole team down even more, Kelley said. “We’ve wasted everybody’s time.”

While Zig is relatively small, it’s had an outsize impact. The language was used to create Bun, for instance, which was later acquired by Anthropic. The AI ban later stirred drama between Bun and Zig.

AI-assisted code has ripped through Silicon Valley, thanks to tools like Claude Code and OpenAI’s Codex. Some use AI to edit or modify their code; others use it to draft it entirely. Big Tech companies have projected lofty goals for the percentage of code that should be — and already is — written with AI.

Zig doesn’t have a mandate to be maximally efficient like these public companies. Instead, “mentorship” is part of its core mission, Kelley said, making AI contributions counterproductive.

“We’re all trying to get better at programming,” Kelley said. “People who are sending AI pull requests, those people are not helping this goal.”

These AI coders are “drive-by contributors,” those who may submit a pull request or two, but will never join the core team, Kelley said.

The AI ban is also simpler. Kelley said that if he tried to say only “good” AI pull requests would be accepted, the reviewers would have to judge each one.

“If I say none whatsoever, then it’s a very easy policy to enforce,” he said.