Zig's Creator Torches Bun's AI Rewrite as Anthropic Sells the Hype

Ray Myers uses the Bun runtime’s port from Zig to Rust as a lens on how AI vendors shape industry narratives. Bun, acquired by Anthropic, was rewritten from Zig to unsafe Rust in a largely agentic process claiming near-100% AI authorship, merged days after the experiment began. Anthropic published its rationale only two months later — a delay Myers argues let sensational coverage frame the migration as proof of AI’s raw power rather than an engineering decision. His broader thesis: with $132 billion raised, no profitability, and a trillion-dollar IPO in view, Anthropic has strong incentive to sell a story that AI is about to end software engineering, and that story drives fear-based architecture and staffing choices regardless of its truth.

The piece defends Zig creator Andrew Kelley’s unusually blunt public response, which blamed Bun’s problems on over-reliance on AI agents to write and review code rather than on Zig’s limitations. Myers lays out three competing explanations for what happened — Anthropic’s (Zig couldn’t handle the memory bugs), Kelley’s (Bun’s codebase is a mess of its own making), and his own, which he finds most plausible: management approved the Rust rewrite mainly as marketing, to showcase Anthropic’s Fable model, align with Anthropic’s existing Rust stack, and distance from a Zig ecosystem that bans AI contributions.

Myers also targets Bun’s engineering culture, citing the project’s 2022 recruiting pitch that warned of a nine-month ‘grind’ as a red flag, and reiterating that sustained crunch is well-documented to harm both health and productivity. His stated concern is public literacy about AI in software: he wants the Rust-versus-Zig question judged on technical merit rather than distorted by a vendor’s promotional spectacle, and holds Anthropic — not Bun’s founder or Zig — as the party accountable for the framing.