The Zig project's rationale for their firm anti-AI contribution policy

The Zig project has implemented a strict policy banning the use of large language models (LLMs) in contributions, including pull requests and comments. While English is encouraged, contributors can use their native languages and rely on their own translation tools. Bun, a prominent project written in Zig and acquired by Anthropic in December 2025, recently achieved a 4x performance improvement by adding parallel semantic analysis and multiple codegen units to the LLVM backend. However, Bun does not plan to upstream this due to Zig's strict ban on AI-assisted contributions.