Model comparison

GPT-5.6 Luna vs Muse Spark 1.1

GPT-5.6 Luna is the stronger model overall, scoring 54.6 to 49.9 on the Noometry Index.

Last verified . 35 shared benchmarks.

GPT-5.6 Luna OpenAI

54.6

Rank #30 Confirmed

Muse Spark 1.1 Meta

49.9

Rank #51 Confirmed

Summary

  • They share 35 benchmarks with published results for both. GPT-5.6 Luna scores higher in 6 categories and Muse Spark 1.1 in 4 categories; 6 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-5.6 Luna leads 77.7 to 45.5.
  • The biggest single-benchmark swing is ProofBench: 60% for GPT-5.6 Luna and 39% for Muse Spark 1.1.
  • GPT-5.6 Luna is cheaper at $0.20 / $1.20 per million input/output tokens, against $1.25 / $4.25 for Muse Spark 1.1.
  • GPT-5.6 Luna accepts more context: 1.05M tokens versus 1.05M.

Side by side

GPT-5.6 Luna and Muse Spark 1.1 specifications
GPT-5.6 LunaMuse Spark 1.1
ProviderOpenAIMeta
Noometry Index54.649.9
Released2026-07-092026-04-08
WeightsProprietaryProprietary
Context window1.05M1.05M
Max output128K131K
Input $ / M tokens$0.20$1.25
Output $ / M tokens$1.20$4.25
Results tracked5237

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Category by category

Coding GPT-5.6 Luna leads

GPT-5.6 Luna: 54.5 (#28), Muse Spark 1.1: 51.3 (#40)

Coding benchmarks
BenchmarkGPT-5.6 LunaMuse Spark 1.1
DeepSWE67.2%53.3%
LMArena WebDev15191542
SciCode53.6%58.8%
LMArena Coding14661498
FrontierCode39.8%—
CursorBench35.9%—
WeirdML60.9%—
ALE-Bench1,667—

Agentic & Tool Use GPT-5.6 Luna leads

GPT-5.6 Luna: 34.4 (#45), Muse Spark 1.1: 30.8 (#73)

Agentic & Tool Use benchmarks
BenchmarkGPT-5.6 LunaMuse Spark 1.1
APEX-Agents43%31.8%
GDP.pdf22.7%15%
Vending-Bench 24,0956,520
τ²-bench Banking—40.5%
BALROG45.6%—
GBAEval—7.9%

Reasoning Too close to call

GPT-5.6 Luna: 47.6 (#43), Muse Spark 1.1: 47.1 (#44)

Reasoning benchmarks
BenchmarkGPT-5.6 LunaMuse Spark 1.1
NYT Connections (extended)69.4%84.9%
CritPt20.6%15.1%
LMArena Hard Prompts14511486
DTBench89.1%94.4%
LMCA48.5%49.9%
Surface Evolver Bench61.9%52.5%
Epoch Capabilities Index156.39154.21
ARC-AGI-259.5%—
SimpleBench46.8%—
Kagi LLM Benchmark49.1%—
ARC-AGI-188%—
Chess Puzzles40%—
Mystery Game Puzzles21%—

Math GPT-5.6 Luna leads

GPT-5.6 Luna: 77.7 (#14), Muse Spark 1.1: 45.5 (#76)

Math benchmarks
BenchmarkGPT-5.6 LunaMuse Spark 1.1
ProofBench60%39%
LMArena Math14581483
FrontierMath (Tiers 1-3)82.1%—
FrontierMath Tier 461%—
OTIS Mock AIME 2024-202598.3%—

Knowledge GPT-5.6 Luna leads

GPT-5.6 Luna: 58.5 (#34), Muse Spark 1.1: 53.1 (#59)

Knowledge benchmarks
BenchmarkGPT-5.6 LunaMuse Spark 1.1
SimpleQA Verified41%57.8%
LMArena Expert14781478
GPQA Diamond91.6%—

Multimodal Too close to call

GPT-5.6 Luna: 42.7 (#28), Muse Spark 1.1: 42.6 (#29)

Multimodal benchmarks
BenchmarkGPT-5.6 LunaMuse Spark 1.1
LMArena Vision12581293
LMArena Document14571465
Blueprint-Bench 222.6%—
Furniture Assembly42.5%—

Multilingual Muse Spark 1.1 leads

GPT-5.6 Luna: 52.8 (#78), Muse Spark 1.1: 56.7 (#17)

Multilingual benchmarks
BenchmarkGPT-5.6 LunaMuse Spark 1.1
LMArena Non-English14171472
LMArena Chinese14701518
LMArena French14561494
LMArena German14541466
LMArena Japanese14111451
LMArena Korean14151458
LMArena Russian14281483
LMArena Spanish14481464

Instruction Following Too close to call

GPT-5.6 Luna: 75.6 (#57), Muse Spark 1.1: 76.5 (#39)

Instruction Following benchmarks
BenchmarkGPT-5.6 LunaMuse Spark 1.1
LMArena Instruction Following14371457

Long Context Too close to call

GPT-5.6 Luna: 43.9 (#82), Muse Spark 1.1: 44.8 (#58)

Long Context benchmarks
BenchmarkGPT-5.6 LunaMuse Spark 1.1
LMArena Longer Query14361462

Writing & Preference Muse Spark 1.1 leads

GPT-5.6 Luna: 68.0 (#29), Muse Spark 1.1: 73.4 (#11)

Writing & Preference benchmarks
BenchmarkGPT-5.6 LunaMuse Spark 1.1
LMArena Text14311479
LMArena Creative Writing13961437
EQ-Bench Creative Writing18291927
EQ-Bench 411561260
LMArena Multi-Turn14341485

Frequently asked questions

Is GPT-5.6 Luna better than Muse Spark 1.1?

GPT-5.6 Luna is the stronger model overall, scoring 54.6 to 49.9 on the Noometry Index.

Which is cheaper, GPT-5.6 Luna or Muse Spark 1.1?

GPT-5.6 Luna is cheaper. It lists at $0.20 per million input tokens and $1.20 per million output tokens; Muse Spark 1.1 lists at $1.25 and $4.25.

Is GPT-5.6 Luna or Muse Spark 1.1 better for coding?

GPT-5.6 Luna scores higher on coding benchmarks: 54.5 versus 51.3 in the Noometry coding category.

Which has the bigger context window?

GPT-5.6 Luna does, with 1.05M tokens against 1.05M.

How many benchmarks do GPT-5.6 Luna and Muse Spark 1.1 share?

35 benchmarks have published results for both models. GPT-5.6 Luna has 52 scored results on Noometry and Muse Spark 1.1 has 37.

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