In short
How they differ.
Worked out from the figures below. Prices and specs are the makers' own, read Oct 20, 2026.
- GPT-6 Luna reads more at once: a context window of 1M tokens against 1M.
- Muse Spark Open can be downloaded and run on your own machine; GPT-6 Luna can't.
- No independent board we follow ranks both models yet.
Side by side
The specs.
| GPT-6 Luna | Muse Spark Open | |
|---|---|---|
| Made by | OpenAI · US | Meta · US |
| Released | Sep 22, 2026 | Oct 15, 2026 |
| Price per 1M tokens | $0.10 in / $0.50 out | Free to download; hosts set prices |
| Context window | 1M | 1M |
| Takes in | text, image | text, image, video, audio |
| Download and run it yourself | No | Yes (Muse Model License) |
| Size | Not published | 816B parameters, 42B active |
| Maker says | “Our most efficient model for focused, high-volume tasks.” | “The most capable US open-weight model to date. Build your way, anywhere.” |
| Sources | Prices, Oct 20, 2026 · Description | Prices, Oct 20, 2026 · Description |
Independent tests
Where they place.
Position on each board we follow (1 is best). Epoch AI's and Vectara's scores are shown; the other boards are linked for their own figures.
More comparisons