Model Comparison
GPT-5.6 Luna vs Muse Spark 1.1Which is better in 2026?
GPT-5.6 Luna shows notably better performance in the majority of benchmarks. Muse Spark 1.1 is 1.1x cheaper per token.
Verdict: GPT-5.6 Luna vs Muse Spark 1.1 — which is better?
GPT-5.6 Luna (by OpenAI) and Muse Spark 1.1 (by Meta) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.
GPT-5.6 Luna outperforms in 2 benchmarks (SWE-Bench Pro, Terminal-Bench 2.1), while Muse Spark 1.1 is better at 1 benchmark (Toolathlon). GPT-5.6 Luna shows notably better performance in the majority of benchmarks.
On price, Muse Spark 1.1 is roughly 1.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5.6 Luna also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose GPT-5.6 Luna if…
- you want the strongest raw capability — it leads on 2 of 3 shared benchmarks
- you process long inputs — it offers a 1,050,000 token context window
Choose Muse Spark 1.1 if…
- cost matters — it's about 1.1x cheaper per token
Performance Benchmarks
Comparative analysis across standard metrics
GPT-5.6 Luna outperforms in 2 benchmarks (SWE-Bench Pro, Terminal-Bench 2.1), while Muse Spark 1.1 is better at 1 benchmark (Toolathlon).
GPT-5.6 Luna shows notably better performance in the majority of benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5.6 Luna ($1.00/1M tokens) is 1.3x cheaper than Muse Spark 1.1 ($1.25/1M tokens).
For output processing, GPT-5.6 Luna ($6.00/1M tokens) is 1.4x more expensive than Muse Spark 1.1 ($4.25/1M tokens).
In conclusion, GPT-5.6 Luna is more expensive than Muse Spark 1.1.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5.6 Luna accepts 1,050,000 input tokens compared to Muse Spark 1.1's 1,048,576 tokens. Muse Spark 1.1 can generate longer responses up to 131,072 tokens, while GPT-5.6 Luna is limited to 128,000 tokens.
Input Capabilities
Supported data types and modalities
Both GPT-5.6 Luna and Muse Spark 1.1 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5.6 Luna
Muse Spark 1.1
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Both models were released on 2026-07-09.
They likely represent similar generations of model development.
Jul 9, 2026
1 weeks ago
Jul 9, 2026
1 weeks ago
Knowledge Cutoff
When training data ends
GPT-5.6 Luna has a documented knowledge cutoff of 2026-02-16, while Muse Spark 1.1's cutoff date is not specified.
We can confirm GPT-5.6 Luna's training data extends to 2026-02-16, but cannot make a direct comparison without Muse Spark 1.1's cutoff date.
Feb 2026
—
Provider Availability
GPT-5.6 Luna is available from OpenAI. Muse Spark 1.1 is available from Meta Model API.
GPT-5.6 Luna
Muse Spark 1.1
Outputs Comparison
Key Takeaways
GPT-5.6 Luna
View detailsOpenAI
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against GPT-5.6 Luna and Muse Spark 1.1 side-by-side, then vote on the output you prefer.
| Feature | | |
|---|
FAQ
Common questions about GPT-5.6 Luna vs Muse Spark 1.1.