GoKawiilBenchmark test finds GPT-5.6 Luna catches fewer bugs than GPT-6 Astra but at 28x lower cost
A new benchmark comparing OpenAI's GPT-5.6 Luna and GPT-6 Astra on code review found Luna verified 69 bugs across 50 pull requests versus Astra's 92, while costing roughly 28 times less per review. Luna also produced more false positives, with 24 of 93 flagged issues failing verification compared to Astra's 4 of 96, and it caught fewer security-related bugs.