GPT-5.6 Luna vs Muse Spark
GPT-5.6 Luna 
Muse Spark Verdict
- Muse Spark leads on quality: 65.6 vs 59.4.
- GPT-5.6 Luna (xhigh) is stronger in composite, long context.
- Muse Spark is stronger in agents & tools, coding, human preference, knowledge, multimodal, reasoning, instruction following, maths.
| Metric | GPT-5.6 Luna (xhigh) | Muse Spark |
|---|---|---|
| BenchLeader Index | 59.4 | 65.6 |
| Agents & tools score | 50.1 | 66.4 |
| Coding score | 60.0 | 66.2 |
| Composite score | 72.9 | 68.6 |
| Human preference score | 65.0 | 69.3 |
| Knowledge score | 59.0 | 64.6 |
| Long context score | 67.4 | 65.5 |
| Multimodal score | 61.6 | 65.9 |
| Reasoning score | 53.9 | 70.2 |
| Instruction following score | – | 79.7 |
| Maths score | – | 56.4 |
| Blended price $/M | $0.450 | – |
| Output speed | 107 tok/s | – |
| Time to first answer | 55.4 s | – |
| Context window | 1M | 262k |
| GPQA Diamond | – | 89.8% |
| OTIS Mock AIME | – | 88.9% |
| Humanity's Last Exam | – | 40.6% |
| SimpleBench | 46.8% | – |
| SciCode | 50.0% | 51.5% |
| ProofBench | – | 17.0% |
| Epoch Capabilities Index | – | 152.1 |
| LMArena Text | 1453 | 1488 |
| LMArena Hard Prompts | 1473 | 1505 |
| LMArena Coding | 1497 | 1526 |
| LMArena WebDev | 1520 | – |
| LMArena Vision | 1254 | 1306 |
| LMArena Agent | 1.1 | – |
| AA Intelligence Index | 34.8 | 31.3 |
| IFBench | – | 75.9% |
| AA-LCR | 81.7% | 78.0% |
| MMMU-Pro | 78.5% | 80.5% |
| AA-Omniscience | -10.8 | 7.2 |
| Terminal-Bench Hard | – | 45.5% |
| GPQA Diamond (AA) | 89.5% | 88.4% |
| Humanity's Last Exam (AA) | 37.0% | 40.7% |
| SciCode (AA) | 50.5% | – |
| τ²-Bench Telecom (AA) | – | 91.5% |
| AIME (Vals) | – | 96.9% |
| MMLU-Pro | – | 87.3% |
| LegalBench | – | 84.2% |
| CorpFin | – | 65.1% |
| TaxEval | – | 77.7% |
| SWE-bench (Vals) | – | 74.4% |
| GPQA Diamond (Vals) | – | 89.7% |
| SWE-Bench Pro | – | 55.0% |
| MCP Atlas | – | 82.2% |
| MultiChallenge | – | 75.5% |
| PRBench Finance | – | 52.4% |
| PRBench Legal | – | 52.3% |
| MultiNRC | – | 59.0% |
| TutorBench | – | 68.5% |
| ARC-AGI-1 | 87.7% | – |
| ARC-AGI-2 | 47.6% | – |
| ARC-AGI-3 | 0.0% | – |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
GPT-5.6 Luna vs Muse Spark: questions
- Is GPT-5.6 Luna better than Muse Spark?
- Muse Spark leads on quality: 65.6 vs 59.4. The BenchLeader Index combines every independent quality benchmark; Muse Spark is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is GPT-5.6 Luna better than Muse Spark for coding?
- Muse Spark scores higher in coding (66 vs 60 on the category index, where 50 is average).
- Is GPT-5.6 Luna better than Muse Spark for agentic tasks?
- Muse Spark scores higher in agentic tasks (66 vs 50 on the category index, where 50 is average).
- Which has the larger context window?
- GPT-5.6 Luna accepts more context: 1M against 262k tokens.