{
  "id": 7392039,
  "title": "GPT-5.6 Luna vs. GPT-6 Astra: Is a $1.20 Model Good Enough for Code Review?",
  "url": "https://urgent.news/2026/09/14/gpt-5-6-luna-vs-gpt-6-astra-is-a-1-20-model-good-enough-for-code",
  "topic": "ai",
  "section": "AI",
  "published": "2026-09-14T19:56:20.000Z",
  "source": {
    "name": "Hacker News",
    "slug": "hacker-news",
    "url": "https://entelligence.ai/blogs/gpt-5.6-luna-vs-gpt-6-astra-is-a-1.20-model-good-enough-for-code-review"
  },
  "original_language": "en",
  "account": "The post compares the performance of GPT-5.6 Luna and GPT-6 Astra, two AI models used to review pull requests for code correctness and security bugs. The key findings are:\n\n1. Price difference: Luna costs $0.20 per million input/output tokens, while Astra costs $10 for input and $50 for output, totaling $5.66 per review.\n\n2. Bug detection: Astra found 92 verified bugs across 50 pull requests, while Luna found 69. Astra found more security bugs (19 vs. Luna's 9).\n\n3. Cost efficiency: Luna achieved 75% of Astra's bug detection for 3.6% of the cost. Astra's cost was 20x higher per verified bug.\n\n4. Correctness issue: Luna had a 28x higher error rate, with 24 of its 93 findings failing verification, compared to Astra's 4 of 96. However, Luna found 9 security bugs that Astra missed.\n\n5. Bug types: Luna had a higher rate of data and logic bugs (39 vs. Astra's 47). Astra excelled in concurrency issues (13 vs. Luna's 10). Luna found 9 security bugs that Astra did not.\n\n6. Cost comparison: Running both models on every PR would have detected 117 of the 143 verified bugs (82%) for a total cost of $5.86, compared to Luna's $0.20 and Astra's $5.66 for a combined $6.86.\n\n7. Training data: Both models were trained on code that was not recent enough to include fixes to the benchmark bugs, giving them an advantage.",
  "summary": null,
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}