Muse Spark 1.3 vs GPT-6 Luna vs Gemini 3.8 Flash
GPT-6 Luna comes out ahead, 83 to 73 and 73 on our weighted score, and it is the cheaper option too.
MetaMuse Spark 1.3
73/100- ECI156.9
- Price$1.25 / $4.25
- Context1.05M
- Our pick
OpenAIGPT-6 Luna
83/100- ECI—
- Price$0.10 / $0.50
- Context1.05M
GoogleGemini 3.8 Flash
73/100- ECI156.9
- Price$0.75 / $3.75
- Context1.05M
GPT-6 Luna is our pick
GPT-6 Luna is the better all-round choice, scoring 83/100 against Muse Spark 1.3 (73) and Gemini 3.8 Flash (73). It leads on capability and price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%. Capability uses the average of shared benchmarks (FrontierMath Tiers 1–3 and OTIS Mock AIME 2024–2025), because GPT-6 Luna has no Capabilities Index score yet.
- CapabilityGPT-6 LunaShared benchmarks: GPT-6 Luna 88.9% · Muse Spark 1.3 86.8% · Gemini 3.8 Flash 83.7%
- Lowest priceGPT-6 LunaGPT-6 Luna $0.20 · Gemini 3.8 Flash $1.50 · Muse Spark 1.3 $2.00 per 1M tokens (3:1 blend)
- Longest contextAbout the sameGPT-6 Luna 1,050,000 · Muse Spark 1.3 1,048,576 · Gemini 3.8 Flash 1,048,576 tokens
- Widest inputsMuse Spark 1.3 and Gemini 3.8 FlashMuse Spark 1.3: Text, Images, PDFs, Audio, Video · GPT-6 Luna: Text, Images, PDFs · Gemini 3.8 Flash: Text, Images, PDFs, Audio, Video
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | Muse Spark 1.3 | GPT-6 Luna | Gemini 3.8 Flash |
|---|---|---|---|---|
| CapabilityShared benchmarks | 50% | 87 | 89 | 84 |
| Price | 25% | 36 | 83 | 42 |
| Inputs & features | 15% | 100 | 80 | 100 |
| Context window | 10% | 61 | 61 | 61 |
| Overall | 100% | 73/100 | 83/100 | 73/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Muse Spark 1.3Meta | GPT-6 LunaOpenAI | Gemini 3.8 FlashGoogle |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 156.9 | — | 156.9 (best) |
| ECI rank | #17 of 148 | — | #15 of 148 (best) |
| GPQA DiamondGraduate-level science questions | — | 90.5% | 95.4% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | 74.4% | 79.0% (best) | 68.4% |
| OTIS Mock AIME 2024–2025Competition mathematics | 99.2% (best) | 98.9% | 98.9% |
| SimpleQA VerifiedShort factual questions | — | 41.4% | 69.7% (best) |
| Price per million tokens | |||
| Input | $1.25 | $0.10 (best) | $0.75 |
| Output | $4.25 | $0.50 (best) | $3.75 |
| Cached input | $0.15 | $0.01 (best) | $0.075 |
| Blended (3:1) | $2.00 | $0.20 (best) | $1.50 |
| Long-context rate | Same rate | Over 272K: $0.20 / $0.75 | Same rate |
| Price source | Official Meta API | Official OpenAI API | Official Google API |
| Limits | |||
| Context window | 1,048,576 tokens | 1,050,000 tokens (best) | 1,048,576 tokens |
| Max output | 131,072 tokens (best) | 128,000 tokens | 65,536 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | Yes |
| Audio | Yes | No | Yes |
| Video | Yes | No | Yes |
| Reasoning | Yesminimal · low · medium · high · xhigh · max | Yeslow · medium · high · xhigh · max | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | muse-spark-1.3 | gpt-6-luna | gemini-3.8-flash |
| API providers | 12 | 24 (best) | 21 |
| Released | Sep 2, 2026 | Sep 22, 2026 | Sep 2, 2026 |
| Knowledge cutoff | — | May 18, 2026 | — |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Muse Spark 1.3$21.00
- GPT-6 Luna$2.00
- Gemini 3.8 Flash$15.00
Which should you choose?
Which is better: Muse Spark 1.3, GPT-6 Luna or Gemini 3.8 Flash?
GPT-6 Luna is the better all-round choice, scoring 83/100 against Muse Spark 1.3 (73) and Gemini 3.8 Flash (73). It leads on capability and price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%. Capability uses the average of shared benchmarks (FrontierMath Tiers 1–3 and OTIS Mock AIME 2024–2025), because GPT-6 Luna has no Capabilities Index score yet.
Which is cheaper, Muse Spark 1.3, GPT-6 Luna or Gemini 3.8 Flash?
GPT-6 Luna is cheaper at $0.10 input / $0.50 output per million tokens (official OpenAI API price). Gemini 3.8 Flash costs $0.75 input / $3.75 output per million tokens (official Google API price); Muse Spark 1.3 costs $1.25 input / $4.25 output per million tokens (official Meta API price). At a typical mix of three input tokens to one output token, that is $0.20 per million tokens for GPT-6 Luna versus $1.50 for Gemini 3.8 Flash (7.5× as much) and $2.00 for Muse Spark 1.3 (10× as much).
Which scores higher on benchmarks?
Not every model here has a Capabilities Index score, so we compare the average of shared benchmarks (FrontierMath Tiers 1–3 and OTIS Mock AIME 2024–2025): GPT-6 Luna 88.9%, Muse Spark 1.3 86.8% and Gemini 3.8 Flash 83.7%. On individual benchmarks: FrontierMath Tiers 1–3 — GPT-6 Luna 79.0%, Muse Spark 1.3 74.4%, Gemini 3.8 Flash 68.4%; OTIS Mock AIME 2024–2025 — Muse Spark 1.3 99.2%, GPT-6 Luna 98.9%, Gemini 3.8 Flash 98.9%.
Which is better for coding?
There are no published SWE-bench Verified results for Muse Spark 1.3, GPT-6 Luna and Gemini 3.8 Flash yet, so there is no like-for-like coding score. On overall capability, GPT-6 Luna leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.
Which has the bigger context window?
Their context windows are effectively the same size: Muse Spark 1.3 1,048,576, GPT-6 Luna 1,050,000 and Gemini 3.8 Flash 1,048,576 tokens. Maximum output per response: Muse Spark 1.3 up to 131,072, GPT-6 Luna up to 128,000, Gemini 3.8 Flash up to 65,536 tokens.
Which can read images, PDFs, audio or video?
Muse Spark 1.3 accepts text, images, PDFs, audio and video; GPT-6 Luna accepts text, images and PDFs; Gemini 3.8 Flash accepts text, images, PDFs, audio and video. Muse Spark 1.3 handles the widest range of inputs.
Are any of these open source?
No. Muse Spark 1.3, GPT-6 Luna and Gemini 3.8 Flash are proprietary and only available through APIs and apps.
Which is newer?
GPT-6 Luna is the newest, released Sep 22, 2026. Muse Spark 1.3 came out Sep 2, 2026; Gemini 3.8 Flash came out Sep 2, 2026. Knowledge cutoff: GPT-6 Luna May 18, 2026.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.
