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GPT-6 Luna vs Muse Spark 1.2

Updated October 21, 2026. 78 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace GPT-6 Luna Replace Muse Spark 1.2
GPT-6 LunaOpenAI
Coding
71.4
Overall
38.1
Output $/M
$0.50
20
Muse Spark 1.2Meta
Coding
65.1
Overall
39.6
Output $/M
$4.25
57
vs boards won of 78 shared, 1 tied

Decision reading

Pick GPT-6 Luna for coding: it scores 71.4 on the Vibe Coding Index against 65.1 for Muse Spark 1.2.

Pick Muse Spark 1.2 when what matters is SciCode or LMArena Text: coding, where it leads.

Model AGPT-6 LunaOpenAI71.4/1002 independent benchmarksNo cost per solved taskModel BMuse Spark 1.2Meta65.1/1002 independent benchmarks$0.64 per solved task
Shared results
78
GPT-6 Luna only
24
Muse Spark 1.2 only
19
Like-for-like categories
8 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

Which one for your work

Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.

At a glance

Coding index
GPT-6 Luna 71.4 from 2 benchmarks, Muse Spark 1.2 65.1 from 2 benchmarks.
Widest category
Knowledge, 17.0 points apart on average over 6 shared benchmarks.
Widest single gap
LiveBench browser: GPT-6 Luna 72.0% against Muse Spark 1.2 36.0%, 36.0 points apart on a 0 to 100 scale.
Output price
GPT-6 Luna $0.50 against Muse Spark 1.2 $4.25 per million output tokens, 8.5x apart.
Context window
GPT-6 Luna takes 1.05M tokens, Muse Spark 1.2 1.05M.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
CategoryGPT-6 LunaBarsMuse Spark 1.2Ties
Coding1031 tie
Intelligence11
Agentic work49
Reasoning16
Math12
Knowledge06
Web design18
General222
All shared boards20571 tie
CodingLike-for-likeFour of these boards feed the Vibe Coding Index103
Coding benchmarks for GPT-6 Luna and Muse Spark 1.2
BenchmarkGPT-6 LunaMuse Spark 1.2Leader
LiveBench coding84.5%78.2%GPT-6 Luna
LMArena WebDev15781534GPT-6 Luna
AA Coding IndexNot measured72.2Only Muse Spark 1.2 measured
SWE-bench Verified (Vals AI)Not measured86.6%Only Muse Spark 1.2 measured
Terminal-Bench 4 (Vals AI)13.6%6.1%GPT-6 Luna
Vibe Code Bench (Vals AI)81.7%79.1%GPT-6 Luna
Code migration (Vals AI)42.5%29.9%GPT-6 Luna
ProgramBench (Vals AI)0.5%0.5%Tie
IOI (Vals AI)55.6%21.8%GPT-6 Luna
Terminal-Bench 2.1 (Vals AI)73.0%69.7%GPT-6 Luna
SWE-bench Multimodal (Vals AI)37.5%Not measuredOnly GPT-6 Luna measured
SkillsBench (Vals AI)Not measured53.0%Only Muse Spark 1.2 measured
CyberBench (Vals AI)76.3%69.5%GPT-6 Luna
SciCode54.6%57.4%Muse Spark 1.2
FrontierCode42.4%Not measuredOnly GPT-6 Luna measured
FrontierSWENot measured12.0%Only Muse Spark 1.2 measured
WeirdMLNot measured60.3%Only Muse Spark 1.2 measured
ALE-Bench1576.9Not measuredOnly GPT-6 Luna measured
LMArena Text: coding14371505Muse Spark 1.2
LMArena Text: software and IT14231505Muse Spark 1.2
LMArena WebDev: React15731526GPT-6 Luna
LMArena WebDev: HTML15951543GPT-6 Luna
LMArena WebDev: from an image1571Not measuredOnly GPT-6 Luna measured
Neither model has a result on the other 15 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index11
Intelligence benchmarks for GPT-6 Luna and Muse Spark 1.2
BenchmarkGPT-6 LunaMuse Spark 1.2Leader
AA Intelligence Index38.139.6Muse Spark 1.2
Epoch Capabilities Index156.8155.1GPT-6 Luna
Agentic workLike-for-likePublic boards, shown as published, kept out of the index49
Agentic work benchmarks for GPT-6 Luna and Muse Spark 1.2
BenchmarkGPT-6 LunaMuse Spark 1.2Leader
AA Agentic IndexNot measured43.2Only Muse Spark 1.2 measured
Design Arena: agents building web apps11891222Muse Spark 1.2
Design Arena: agents building full-stack apps11581210Muse Spark 1.2
Design Arena: agents building mobile apps11331182Muse Spark 1.2
Design Arena: agents building Android appsNot measured1228Only Muse Spark 1.2 measured
Design Arena: agents building gamesNot measured1179Only Muse Spark 1.2 measured
Design Arena: HTML slidesNot measured1135Only Muse Spark 1.2 measured
Design Arena: PowerPoint slidesNot measured1198Only Muse Spark 1.2 measured
LiveBench research43.5%67.7%Muse Spark 1.2
LiveBench browser72.0%36.0%GPT-6 Luna
LiveBench long agentic48.1%21.3%GPT-6 Luna
SREBench (Vals AI)2.7%0.0%GPT-6 Luna
Finance Agent (Vals AI)49.9%60.6%Muse Spark 1.2
Tax Agent Bench (Vals AI)19.9%32.8%Muse Spark 1.2
Legal Research Bench (Vals AI)30.3%43.8%Muse Spark 1.2
Harvey's Legal Agent Benchmark (Vals AI)4.2%Not measuredOnly GPT-6 Luna measured
Excel Modeling Benchmark (Vals AI)68.5%57.0%GPT-6 Luna
BioMysteryBench (Vals AI)61.5%64.8%Muse Spark 1.2
Terminal-Bench-Science (Vals AI)4.3%Not measuredOnly GPT-6 Luna measured
Vals Science Index28.4%Not measuredOnly GPT-6 Luna measured
APEX-Agents44.3%45.4%Muse Spark 1.2
SpireClimb0.0%Not measuredOnly GPT-6 Luna measured
Neither model has a result on the other 17 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index16
Reasoning benchmarks for GPT-6 Luna and Muse Spark 1.2
BenchmarkGPT-6 LunaMuse Spark 1.2Leader
LiveBench reasoning81.8%90.0%Muse Spark 1.2
MysteryMechanism (Vals AI)19.4%Not measuredOnly GPT-6 Luna measured
MMMU Pro (Vals AI)Not measured86.1%Only Muse Spark 1.2 measured
GPQA Diamond (Artificial Analysis run)Not measured90.4%Only Muse Spark 1.2 measured
Humanity's Last Exam (Artificial Analysis run)38.5%45.5%Muse Spark 1.2
GPQA Diamond (Epoch AI run)90.5%Not measuredOnly GPT-6 Luna measured
ARC-AGI86.7%Not measuredOnly GPT-6 Luna measured
ARC-AGI-259.3%Not measuredOnly GPT-6 Luna measured
SimpleBenchNot measured74.5%Only Muse Spark 1.2 measured
Chess puzzles36.0%27.0%GPT-6 Luna
Mystery game puzzles7.0%Not measuredOnly GPT-6 Luna measured
LMArena Text: hard prompts14101489Muse Spark 1.2
LMArena Text: expert14421475Muse Spark 1.2
LMArena Text: hard prompts in English14101487Muse Spark 1.2
LMArena Vision: diagrams12451317Muse Spark 1.2
LMArena Vision: homework1261Not measuredOnly GPT-6 Luna measured
Neither model has a result on the other 5 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index12
Math benchmarks for GPT-6 Luna and Muse Spark 1.2
BenchmarkGPT-6 LunaMuse Spark 1.2Leader
OTIS Mock AIME98.9%Not measuredOnly GPT-6 Luna measured
FrontierMath, tiers 1 to 378.9%Not measuredOnly GPT-6 Luna measured
FrontierMath, tier 456.1%Not measuredOnly GPT-6 Luna measured
ProofBench64.0%43.0%GPT-6 Luna
LMArena Text: math14091484Muse Spark 1.2
LMArena Text: mathematical work14271480Muse Spark 1.2
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index06
Knowledge benchmarks for GPT-6 Luna and Muse Spark 1.2
BenchmarkGPT-6 LunaMuse Spark 1.2Leader
MMLU ProNot measured88.3%Only Muse Spark 1.2 measured
LegalBench (Vals AI)Not measured85.3%Only Muse Spark 1.2 measured
CorpFin (Vals AI)Not measured70.9%Only Muse Spark 1.2 measured
TaxEval (Vals AI)Not measured80.4%Only Muse Spark 1.2 measured
MortgageTax (Vals AI)Not measured65.4%Only Muse Spark 1.2 measured
MedCode (Vals AI)44.7%49.4%Muse Spark 1.2
SimpleQA Verified41.4%60.3%Muse Spark 1.2
LMArena Text: science13861500Muse Spark 1.2
LMArena Text: medicine and healthcare13521496Muse Spark 1.2
LMArena Text: legal and government14001517Muse Spark 1.2
LMArena Text: business and finance13881484Muse Spark 1.2
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index18
Web design benchmarks for GPT-6 Luna and Muse Spark 1.2
BenchmarkGPT-6 LunaMuse Spark 1.2Leader
Design Arena: websites12721313Muse Spark 1.2
Design Arena: UI components12971300Muse Spark 1.2
Design Arena: game dev12591302Muse Spark 1.2
Design Arena: data viz12151334Muse Spark 1.2
Design Arena: 3D12171301Muse Spark 1.2
Design Arena: all code categories12711313Muse Spark 1.2
Design Arena: SVG12531285Muse Spark 1.2
Design Arena: ASCII art11561284Muse Spark 1.2
LiveBench design82.5%67.1%GPT-6 Luna
GeneralLike-for-likePublic boards, shown as published, kept out of the index222
General benchmarks for GPT-6 Luna and Muse Spark 1.2
BenchmarkGPT-6 LunaMuse Spark 1.2Leader
Vals Index52.3%Not measuredOnly GPT-6 Luna measured
LiveBench data analysis73.4%76.5%Muse Spark 1.2
Public Benefits Bench (Vals AI)57.6%68.5%Muse Spark 1.2
SAGE (Vals AI)48.1%47.7%GPT-6 Luna
MedScribe (Vals AI)83.7%90.1%Muse Spark 1.2
Vals Multimodal IndexNot measured69.8%Only Muse Spark 1.2 measured
Long context reasoning (AA-LCR)83.3%79.0%GPT-6 Luna
DTBench90.1%94.7%Muse Spark 1.2
LMCA44.5%48.4%Muse Spark 1.2
Furniture assembly44.2%Not measuredOnly GPT-6 Luna measured
LMArena Text13891482Muse Spark 1.2
LMArena Text: instruction following14081462Muse Spark 1.2
LMArena Text: creative writing13631436Muse Spark 1.2
LMArena Vision12161304Muse Spark 1.2
LMArena Text: English13931483Muse Spark 1.2
LMArena Text: non-English13811476Muse Spark 1.2
LMArena Text: Chinese14271509Muse Spark 1.2
LMArena Text: German1376Not measuredOnly GPT-6 Luna measured
LMArena Text: Japanese1369Not measuredOnly GPT-6 Luna measured
LMArena Text: Korean13591462Muse Spark 1.2
LMArena Text: French14081495Muse Spark 1.2
LMArena Text: Spanish13911484Muse Spark 1.2
LMArena Text: Russian13921483Muse Spark 1.2
LMArena Text: Polish1383Not measuredOnly GPT-6 Luna measured
LMArena Text: multi-turn13921502Muse Spark 1.2
LMArena Text: longer queries14081473Muse Spark 1.2
LMArena Text: writing and language13841453Muse Spark 1.2
LMArena Text: entertainment and media13641443Muse Spark 1.2
LMArena Vision: English12041291Muse Spark 1.2
LMArena Vision: Chinese1266Not measuredOnly GPT-6 Luna measured
LMArena Vision: reading text12251313Muse Spark 1.2
LMArena Vision: creative writing1205Not measuredOnly GPT-6 Luna measured
Neither model has a result on the other 14 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for GPT-6 Luna and Muse Spark 1.2
BenchmarkGPT-6 LunaMuse Spark 1.2Leader
Neither model has a result on 5 boards here

What each workload costs

Three fixed token mixes at each model's listed price, so per-token rates become a bill.

Chat turn

1K input + 500 output tokens

GPT-6 Luna$0.0003Fits in one request
Muse Spark 1.2$0.0034Fits in one request

GPT-6 Luna costs less

Repository review

50K input + 3K output tokens

GPT-6 Luna$0.0065Fits in one request
Muse Spark 1.2$0.075Fits in one request

GPT-6 Luna costs less

Agent loop

200K input + 10K output tokens

GPT-6 Luna$0.025Fits in one request
Muse Spark 1.2$0.292Fits in one request

GPT-6 Luna costs less

Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.

Specification differences

The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.

Specifications of GPT-6 Luna and Muse Spark 1.2
SpecificationOpenAI GPT-6 LunaMeta Muse Spark 1.2
MakerOpenAIMeta
WeightsNo public weights listedNo public weights listed
ReleasedSeptember 22, 2026August 5, 2026
Context window1.05M1.05M
Input $/Mtok$0.10$1.25
Output $/Mtok$0.50$4.25
Coding index71.465.1
Independent measurements behind it22
Cost per solved taskNot computable$0.64
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-6 Luna better than Muse Spark 1.2 for coding?

Pick GPT-6 Luna for coding: it scores 71.4 on the Vibe Coding Index against 65.1 for Muse Spark 1.2. Pick Muse Spark 1.2 when what matters is SciCode or LMArena Text: coding, where it leads.

Which is cheaper, GPT-6 Luna or Muse Spark 1.2?

GPT-6 Luna costs $0.10 per million input tokens and $0.50 per million output tokens; Muse Spark 1.2 costs $1.25 and $4.25. Cost per solved task is known for Muse Spark 1.2 only.

Which has the bigger context window, GPT-6 Luna or Muse Spark 1.2?

GPT-6 Luna, with 1.05M tokens against 1.05M.

How many benchmarks is the GPT-6 Luna vs Muse Spark 1.2 comparison based on?

78 benchmarks have a result for both models as of October 21, 2026. GPT-6 Luna's coding index rests on 2 independent benchmarks and Muse Spark 1.2's on 2. Where only one model has a result, the page says so instead of naming a winner.

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<iframe src="https://llmbenchmark.ai/embed/compare/gpt-6-luna-vs-meta-muse-spark-1-2" title="GPT-6 Luna vs Muse Spark 1.2, LLMBenchmark.ai" width="100%" height="360" style="border:0;max-width:100%" loading="lazy"></iframe>
<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/gpt-6-luna-vs-meta-muse-spark-1-2">LLMBenchmark.ai, GPT-6 Luna vs Muse Spark 1.2</a></p>