GPT-5.6 Luna vs. GPT-6 Astra: Is a $1.20 Model Good Enough for Code Review?
Entelligence benchmarks GPT-5.6 Luna ($1.20/M output) against GPT-6 Astra for code review: Luna found 69 verified bugs at 3.6% of Astra's cost.
Entelligence compared GPT-5.6 Luna ($0.20/$1.20 per million tokens) against GPT-6 Astra ($10/$50) on 50 benchmark pull requests from Cal.com, Sentry, Discourse, Keycloak, and Grafana. Astra verified 92 bugs versus Luna's 69, with precision of 96% versus 74%, and Astra caught 19 of 24 security bugs while Luna found only 9. Luna cost $0.20 total versus Astra's $5.66 and reviewed faster at 23 seconds versus 36, with the widest quality gap on Keycloak authentication and permission logic (6 vs 14 verified bugs). Running both models would find 82% of the 143 verified bugs for $5.86 total.
- Luna found 75% of Astra's verified bugs for 3.6% of the cost.
- Astra precision 96% vs Luna 74%; one in four Luna findings failed verification.
- Security bug detection gap: Astra 19/24, Luna 9/24.
- Worst gap on Keycloak identity and access management pull requests.
- Authors caution benchmark PRs predate both models' training cutoffs.
From the original article
9 min read at entelligence.ai
GPT-5. 6 Luna costs $0. 20 per million input tokens and $1.
By theanonymousone · entelligence.ai
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