GPT-5.6 Luna vs GPT-6 Astra: 28× Cheaper, but Weaker on Security
Across 50 pull requests, Luna caught 75% of Astra's bugs at just 3.6% of the cost. On security code, it found 9 of 24 vulnerabilities versus Astra's 19.
Across 50 pull requests, GPT-5.6 Luna found 69 real bugs while GPT-6 Astra found 92. Precision: 74% for Luna versus 96% for Astra. A full run cost $0.20 versus $5.66 — a 28× difference.
As a vibe coder, I'd reach for Luna for routine reviews: at a fraction of the cost, it catches 75% of what Astra does. But on security-sensitive code — authorization, access control — it found only 9 of 24 vulnerabilities, while Astra found 19 of 24. That's not a place I'd cut corners on the model.
Source: entelligence.ai
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Author
Evgenii Arsentev
PhD · Chief Executive Officer, digital health
Articles · Latest articles