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Grok 4.20 Beta
amazon-nova-experimental-chat
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Gemma 4 31B
Step 5 Preview
GPT-5.6 Luna
GPT-5.6 Luna is a proprietary model from OpenAI, released Jul 9, 2026. It ranks #94 of 351 on the LMArena text leaderboard with a rating of 1431. It costs $0.20 per million input tokens and $1.20 per million output tokens, with a 1.1M-token context window.
- Developer
- OpenAI
- Released
- Jul 9, 2026
- Context window
- 1.1M
- Price in / out, per 1M tokens
- $0.20 / $1.20
- Weights
- Proprietary
- Inputs
- Files, Images, Text
- Reasoning
- Yes
- Tool use
- Yes
Benchmarks
| Benchmark | Score bar | Accuracy | Rank | Cost / test |
|---|---|---|---|---|
| Terminal-Bench 4.0Coding | 11.62% | 38 / 55 | $0.73 | |
| SWE-benchCoding | 93.00% | 9 / 85 | $0.04 | |
| Vibe Code BenchCoding | 77.06% | 34 / 115 | $0.73 | |
| Tax Agent BenchFinance | 24.82% | 42 / 76 | $0.47 | |
| Legal Research BenchLaw | 36.54% | 43 / 85 | $0.85 | |
| MedCodeMedicine | 42.39% | 51 / 107 | $0.2 / $1.2 | |
| GPQA DiamondReasoning | 91.67% | 18 / 138 | $0.2 / $1.2 | |
| MMLU-ProReasoning | 86.04% | 50 / 138 | $0.2 / $1.2 | |
| MMMUReasoning | 85.03% | 25 / 93 | $0.2 / $1.2 | |
| Terminal-Bench ScienceReasoning | 0.00% | 40 / 42 | $0.58 |
Vals AI, as of Oct 24, 2026.
LMArena, by category
| Leaderboard | Rating | Rank | Votes |
|---|---|---|---|
| TextLMArena | 1431 | 94 / 351 | 41.4K |
| CodingLMArena | 1467 | 75 / 346 | 11.2K |
| MathLMArena | 1459 | 60 / 339 | 1.9K |
| Creative writingLMArena | 1396 | 107 / 349 | 8.7K |
| Instruction followingLMArena | 1438 | 62 / 351 | 14.7K |
| Hard promptsLMArena | 1452 | 70 / 351 | 27.2K |
| Multi-turnLMArena | 1435 | 94 / 349 | 6.7K |
| Long queriesLMArena | 1436 | 84 / 330 | 19.5K |
| ExpertLMArena | 1478 | 51 / 305 | 4.7K |
| Legal and governmentIndustries | 1446 | 74 / 325 | 3.5K |
| Medicine and healthcareIndustries | 1398 | 159 / 325 | 3.1K |
| Business and financeIndustries | 1439 | 58 / 344 | 7.8K |
| ChineseLanguages | 1470 | 86 / 328 | 3.2K |
| SpanishLanguages | 1445 | 72 / 249 | 1.2K |
| GermanLanguages | 1455 | 46 / 261 | 711 |
| FrenchLanguages | 1457 | 71 / 252 | 1.4K |
| JapaneseLanguages | 1416 | 57 / 236 | 657 |
| WebDevLMArena | 1519 | 57 / 124 | 12.6K |
| VisionLMArena | 1257 | 58 / 146 | 11.1K |
LMArena, CC BY 4.0, as of Oct 22, 2026. Where a model is rated at several effort levels, its best is shown (GPT-5.6 Luna (xHigh), GPT-5.6 Luna (xHigh, Codex Harness)).
Compare GPT-5.6 Luna
OpenAI
The lab behind GPT and ChatGPT, which brought large language models to hundreds of millions of people. Founded 2015, based in San Francisco. openai.com
Questions
Who makes GPT-5.6 Luna?
GPT-5.6 Luna is made by OpenAI, founded 2015 and based in San Francisco.
How much does GPT-5.6 Luna cost?
$0.20 per million input tokens and $1.20 per million output tokens, at its provider’s list price.
What is GPT-5.6 Luna’s context window?
1.1M tokens (1,050,000).
How does GPT-5.6 Luna rank?
#94 of 351 on LMArena’s text leaderboard, rated 1431 (95% interval 1427–1435) from 41,426 votes, as of Oct 22, 2026.
Is GPT-5.6 Luna open source?
No. GPT-5.6 Luna is proprietary and served through its provider’s API.