# GPT-5.6 Luna vs GPT-6 Astra: Is $1.20 Model Good Enough?

Digest AI · Generative AI & Models · published 2026-09-09T00:00:00Z

Canonical: https://digestai.news/story/gpt-5-6-luna-vs-gpt-6-astra-is-1-20-model-good-enough

## Summary

The article compares the cost and effectiveness of two AI models, GPT-5.6 Luna and GPT-6 Astra, in code review tasks. While Astra is more expensive at $10 per million input tokens and output tokens, it finds significantly more bugs (92 vs 69) across 50 pull requests. Luna costs only $0.20 for the same amount of work but misses more bugs (24 vs 4). The article highlights that Astra is better at identifying security bugs, while Luna performs well on correctness and concurrency issues. Despite these differences, both models cost around $5.86 per run, which is a significant portion of their combined output price. The study also notes the importance of context in AI model performance and suggests running multiple runs to catch all potential bugs.

## Key points

- GPT-5.6 Luna costs $0.20 per million tokens for input and output
- GPT-6 Astra costs $10 per million tokens for input and output
- Luna finds 69 verified bugs, while Astra finds 92

## Why it matters

This comparison is crucial for companies considering which AI model to use in their code review processes. It highlights the trade-offs between cost and effectiveness, especially as models like GPT-6 Astra become more expensive.

## Sources

1. [GPT-5.6 Luna vs. GPT-6 Astra: Is a $1.20 Model Good Enough for Code Review?](https://entelligence.ai/blogs/gpt-5.6-luna-vs-gpt-6-astra-is-a-1.20-model-good-enough-for-code-review) (entelligence.ai, 2026-09-09)

Part of the developing story: [OpenAI Unveils GPT-6 Astra Amid Controversy](https://digestai.news/thread/openais-gpt6-astra-faces-postlaunch-quality-drop-claims) (5 stories)

## Cite

Digest AI, "GPT-5.6 Luna vs GPT-6 Astra: Is $1.20 Model Good Enough?", 9 September 2026, https://digestai.news/story/gpt-5-6-luna-vs-gpt-6-astra-is-1-20-model-good-enough

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