AI-Generated Code Ships Faster, But Crashes Harder

Machine-Written Pull Requests Contain 70% More Bugs Rashmi Ramesh (rashmiramesh_) • December 19, 2025

Artificial intelligence coding assistants write code faster than humans. They also write buggier code, though nobody puts that in the marketing materials.

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Researchers at code review tool CodeRabbit analyzed 470 open-source pull requests on GitHub, analyzing AI-coauthored submissions against human-only contributions for their logic, maintainability, security and performance.

AI-generated pull requests averaged nearly 11 issues each, compared with roughly six in human-generated submissions, resulting in longer review cycles and higher risk of defects reaching production.

Beyond the volume, the severity of the bugs also escalated with AI involvement. CodeRabbit classifies issues as "critical" when they could cause system failures, security breaches or data loss, and "major" when they significantly impact functionality or performance. Both categories appeared substantially more often in machine-written code.

AI-generated code showed ...