specs at a glance
| Leaderboard rank | #8 of 29 |
|---|---|
| SWE-bench Verified | 93.0% |
| SWE-bench Pro | — |
| Terminal-Bench | — |
| Input price / 1M | $0.20 |
| Output price / 1M | $1.20 |
| Context window | — |
| Open weights | No |
| Access | API |
| Maker | OpenAI |
how good is GPT-5.6 Luna at coding?
GPT-5.6 Luna sits at #8 of 29 ranked models, posting 93.0% on SWE-bench Verified — 4 points behind #1 Claude Opus 5.
Score provenance: Independent (vals.ai, eval listed Jul 17 2026, mini-swe-agent bash-only harness): SWE-bench Verified 93.00% ±1.14. Added Jul 21, 2026 — this row was missing from the board even though vals.ai had already evaluated Luna, and our Kimi K3 note referenced its 93.0% score without ever listing it; adding it moves every row below it down one rank. Treat 3rd and 4th as a tie: Kimi K3's 93.40% ±1.11 is 0.4 points higher, well inside the combined margin of error (~0.25 sigma), so the ordering between them is not significant. Like the rest of the GPT-5.6 family, OpenAI has published no SWE-bench Verified figure of its own, so we rank on the independent number per our standing rule. The striking number is cost: vals.ai measured $0.21 per test against $1.15 for GPT-5.6 Sol, $1.92 for Claude Opus 4.8 and $2.05 for Claude Fable 5, at 201s median latency. Pricing added Aug 1, 2026: OpenAI cut Luna 80% on Jul 30, 2026, from $1/$6 to $0.20/$1.20 per 1M, making it the cheapest ranked model on this board per token. Vendor-announced (OpenAI, via its own post and consistent reporting from BleepingComputer and VentureBeat); openai.com/api/pricing returns 403 to our fetcher, so this is a vendor figure rather than one we read off the pricing page ourselves. It had been left blank since Jul 21 for exactly that reason.
what does GPT-5.6 Luna cost?
$0.20 per 1M input tokens and $1.20 per 1M output — #2 cheapest of the 27 models we track. Coding workloads are output-heavy, so weight the output rate when budgeting. Run your own volume through the AI API cost calculator for a monthly estimate.
where can you use it?
Available via API. As a proprietary model, you're on the maker's infrastructure and release schedule.
More coverageAI coding models on GENZ TECH
Ranked on our AI Coding Leaderboard — scores confirmed against primary sources only, updated 2026-09-03.