GPT-5.6 Luna vs Muse Spark 1.1: Specs & Benchmark Comparison

GPT-5.6 Luna is developed by OpenAI, while Muse Spark 1.1 comes from Meta. Both were released in July 2026.

The two models share 4 published benchmarks. GPT-5.6 Luna leads on 3 of them, Muse Spark 1.1 on 1. The widest gaps are on Toolathlon, where Muse Spark 1.1 scores 75.6% against 53.4%; DeepSWE 1.1, where GPT-5.6 Luna scores 67.0% against 53.0%. Averaged across everything we track, GPT-5.6 Luna sits at 51.5% and Muse Spark 1.1 at 70.7%.

GPT-5.6 Luna is the cheaper API at $0.20 per million input tokens and $1.20 per million output tokens, roughly 6 times cheaper than Muse Spark 1.1 at $1.25 and $4.25. Both accept a context window of about 1M tokens. Both accept text and images as input.

CharacteristicGPT-5.6 LunaMuse Spark 1.1
CompanyOpenAIMeta
Release DateJuly 9, 2026July 9, 2026
Parameters
MultimodalYesYes
Context (input)1.1M1.0M
Context (output)128K131K
Input Price / 1M$0.20$1.25
Output Price / 1M$1.20$4.25
Average Score51.5%70.7%
Benchmarks
Toolathlon53.4%75.6%
DeepSWE 1.167.0%53.0%
Terminal-Bench 2.184.7%80.0%
SWE-Bench Pro62.7%61.5%

Visual Benchmark Comparison

GPT-5.6 Luna
Muse Spark 1.1
Toolathlon0.5 vs 0.8
0.5
0.8
DeepSWE 1.10.7 vs 0.5
0.7
0.5
Terminal-Bench 2.10.8 vs 0.8
0.8
0.8
SWE-Bench Pro0.6 vs 0.6
0.6
0.6

Verdict

GPT-5.6 Luna leads in 2 out of 4 comparison categories.

Overall Performance

Both models show comparable average scores: GPT-5.6 Luna — 0.5, Muse Spark 1.1 — 0.7.

API Cost

GPT-5.6 Luna is 3.9x cheaper: input $0.20/1M vs $1.25/1M tokens.

Context Window

GPT-5.6 Luna supports a larger context: 1M vs 1M tokens.

Recency

Both models were released around the same time: 7/9/2026 and 7/9/2026.

More About These Models

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Frequently Asked Questions

Which is better for coding — GPT-5.6 Luna or Muse Spark 1.1?
Direct comparison on the SWE-Bench benchmark is not available. We recommend reviewing other metrics on the comparison page.
Which model is cheaper — GPT-5.6 Luna or Muse Spark 1.1?
GPT-5.6 Luna is cheaper for input: $0.20 per 1M tokens vs $1.25.
Which has a larger context window — GPT-5.6 Luna or Muse Spark 1.1?
GPT-5.6 Luna supports a larger context: 1,050,000 tokens vs 1,000,000.

The GPT-5.6 Luna and Muse Spark 1.1 comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the GPT-5.6 Luna or Muse Spark 1.1 page. See also the complete list of AI model comparisons.