Muse Spark 1.2 vs Muse Spark Open
Updated October 21, 2026. 25 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Pick Muse Spark 1.2 for coding: it scores 65.1 on the Vibe Coding Index against 62.1 for Muse Spark Open.
Pick Muse Spark Open when what matters is Terminal-Bench 4 (Vals AI) or SciCode, where it leads.
- Shared results
- 25
- Muse Spark 1.2 only
- 72
- Muse Spark Open only
- 1
- Like-for-like categories
- 6 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.
Coding
Vibe Coding Index, four public coding benchmarks
Muse Spark 1.2
Muse Spark 1.2 scores 65.1 against 62.1.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
No call
Only Muse Spark 1.2 has a AA Intelligence Index result, 39.6.
Directional only
Agentic work
AA Agentic Index
No call
Only Muse Spark 1.2 has a AA Agentic Index result, 43.2.
Directional only
Knowledge
MMLU Pro
No call
Only Muse Spark 1.2 has a MMLU Pro result, 88.3%.
Directional only
Web design
Design Arena: websites
Muse Spark 1.2
Muse Spark 1.2 leads, 1313 against 1311.
Same board, both measured
Long documents
Listed context window
No call
Both take 1.05M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
No call
Muse Spark 1.2 $0.0034, Muse Spark Open $0.0034 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Muse Spark 1.2 has the number, $0.64.
Directional only
At a glance
- Coding index
- Muse Spark 1.2 65.1 from 2 benchmarks, Muse Spark Open 62.1 from 2 benchmarks.
- Widest category
- General, 8.5 points apart on average over 2 shared benchmarks.
- Widest single gap
- LiveBench data analysis: Muse Spark 1.2 76.5% against Muse Spark Open 60.2%, 16.3 points apart on a 0 to 100 scale.
- Output price
- Both cost $4.25 per million output tokens.
- Context window
- Both take 1.05M tokens.
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.
| Category | Muse Spark 1.2 | Bars | Muse Spark Open | Ties |
|---|---|---|---|---|
| Coding | 5 | 3 | ||
| Intelligence | 0 | 1 | ||
| Agentic work | 5 | 2 | 1 tie | |
| Reasoning | 3 | 0 | ||
| Web design | 3 | 0 | ||
| General | 2 | 0 | ||
| All shared boards | 18 | 6 | 1 tie |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index53
| Benchmark | Muse Spark 1.2 | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench coding | 78.2% | 73.6% | Muse Spark 1.2 |
| LMArena WebDev | 1534 | 1528 | Muse Spark 1.2 |
| AA Coding Index | 72.2 | Not measured | Only Muse Spark 1.2 measured |
| SWE-bench Verified (Vals AI) | 86.6% | Not measured | Only Muse Spark 1.2 measured |
| Terminal-Bench 4 (Vals AI) | 6.1% | 6.6% | Muse Spark Open |
| Vibe Code Bench (Vals AI) | 79.1% | 76.2% | Muse Spark 1.2 |
| Code migration (Vals AI) | 29.9% | 21.2% | Muse Spark 1.2 |
| ProgramBench (Vals AI) | 0.5% | Not measured | Only Muse Spark 1.2 measured |
| IOI (Vals AI) | 21.8% | Not measured | Only Muse Spark 1.2 measured |
| Terminal-Bench 2.1 (Vals AI) | 69.7% | Not measured | Only Muse Spark 1.2 measured |
| SkillsBench (Vals AI) | 53.0% | Not measured | Only Muse Spark 1.2 measured |
| CyberBench (Vals AI) | 69.5% | Not measured | Only Muse Spark 1.2 measured |
| SciCode | 57.4% | 58.4% | Muse Spark Open |
| FrontierSWE | 12.0% | Not measured | Only Muse Spark 1.2 measured |
| WeirdML | 60.3% | Not measured | Only Muse Spark 1.2 measured |
| ALE-Bench | Not measured | 1590.1 | Only Muse Spark Open measured |
| LMArena Text: coding | 1505 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: software and IT | 1505 | Not measured | Only Muse Spark 1.2 measured |
| LMArena WebDev: React | 1526 | 1529 | Muse Spark Open |
| LMArena WebDev: HTML | 1543 | 1495 | Muse Spark 1.2 |
| Neither model has a result on the other 18 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Muse Spark 1.2 | Muse Spark Open | Leader |
|---|---|---|---|
| AA Intelligence Index | 39.6 | Not measured | Only Muse Spark 1.2 measured |
| Epoch Capabilities Index | 155.1 | 155.1 | Muse Spark Open |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index52
| Benchmark | Muse Spark 1.2 | Muse Spark Open | Leader |
|---|---|---|---|
| AA Agentic Index | 43.2 | Not measured | Only Muse Spark 1.2 measured |
| Design Arena: agents building web apps | 1222 | Not measured | Only Muse Spark 1.2 measured |
| Design Arena: agents building full-stack apps | 1210 | Not measured | Only Muse Spark 1.2 measured |
| Design Arena: agents building mobile apps | 1182 | Not measured | Only Muse Spark 1.2 measured |
| Design Arena: agents building Android apps | 1228 | Not measured | Only Muse Spark 1.2 measured |
| Design Arena: agents building games | 1179 | Not measured | Only Muse Spark 1.2 measured |
| Design Arena: HTML slides | 1135 | Not measured | Only Muse Spark 1.2 measured |
| Design Arena: PowerPoint slides | 1198 | Not measured | Only Muse Spark 1.2 measured |
| LiveBench research | 67.7% | 80.3% | Muse Spark Open |
| LiveBench browser | 36.0% | 36.0% | Tie |
| LiveBench long agentic | 21.3% | 18.9% | Muse Spark 1.2 |
| SREBench (Vals AI) | 0.0% | Not measured | Only Muse Spark 1.2 measured |
| Finance Agent (Vals AI) | 60.6% | 61.3% | Muse Spark Open |
| Tax Agent Bench (Vals AI) | 32.8% | 26.3% | Muse Spark 1.2 |
| Legal Research Bench (Vals AI) | 43.8% | 38.5% | Muse Spark 1.2 |
| Excel Modeling Benchmark (Vals AI) | 57.0% | 53.7% | Muse Spark 1.2 |
| BioMysteryBench (Vals AI) | 64.8% | Not measured | Only Muse Spark 1.2 measured |
| APEX-Agents | 45.4% | 33.4% | Muse Spark 1.2 |
| Neither model has a result on the other 21 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | Muse Spark 1.2 | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench reasoning | 90.0% | 73.7% | Muse Spark 1.2 |
| MMMU Pro (Vals AI) | 86.1% | Not measured | Only Muse Spark 1.2 measured |
| GPQA Diamond (Artificial Analysis run) | 90.4% | 89.0% | Muse Spark 1.2 |
| Humanity's Last Exam (Artificial Analysis run) | 45.5% | 43.9% | Muse Spark 1.2 |
| SimpleBench | 74.5% | Not measured | Only Muse Spark 1.2 measured |
| Chess puzzles | 27.0% | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: hard prompts | 1489 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: expert | 1475 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: hard prompts in English | 1487 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Vision: diagrams | 1317 | Not measured | Only Muse Spark 1.2 measured |
| Neither model has a result on the other 11 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index3 boards, none shared
| Benchmark | Muse Spark 1.2 | Muse Spark Open | Leader |
|---|---|---|---|
| ProofBench | 43.0% | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: math | 1484 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: mathematical work | 1480 | Not measured | Only Muse Spark 1.2 measured |
| Neither model has a result on the other 10 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index11 boards, none shared
| Benchmark | Muse Spark 1.2 | Muse Spark Open | Leader |
|---|---|---|---|
| MMLU Pro | 88.3% | Not measured | Only Muse Spark 1.2 measured |
| LegalBench (Vals AI) | 85.3% | Not measured | Only Muse Spark 1.2 measured |
| CorpFin (Vals AI) | 70.9% | Not measured | Only Muse Spark 1.2 measured |
| TaxEval (Vals AI) | 80.4% | Not measured | Only Muse Spark 1.2 measured |
| MortgageTax (Vals AI) | 65.4% | Not measured | Only Muse Spark 1.2 measured |
| MedCode (Vals AI) | 49.4% | Not measured | Only Muse Spark 1.2 measured |
| SimpleQA Verified | 60.3% | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: science | 1500 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: medicine and healthcare | 1496 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: legal and government | 1517 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: business and finance | 1484 | Not measured | Only Muse Spark 1.2 measured |
| Neither model has a result on the other 6 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | Muse Spark 1.2 | Muse Spark Open | Leader |
|---|---|---|---|
| Design Arena: websites | 1313 | 1311 | Muse Spark 1.2 |
| Design Arena: UI components | 1300 | Not measured | Only Muse Spark 1.2 measured |
| Design Arena: game dev | 1302 | 1290 | Muse Spark 1.2 |
| Design Arena: data viz | 1334 | Not measured | Only Muse Spark 1.2 measured |
| Design Arena: 3D | 1301 | Not measured | Only Muse Spark 1.2 measured |
| Design Arena: all code categories | 1313 | Not measured | Only Muse Spark 1.2 measured |
| Design Arena: SVG | 1285 | Not measured | Only Muse Spark 1.2 measured |
| Design Arena: ASCII art | 1284 | Not measured | Only Muse Spark 1.2 measured |
| LiveBench design | 67.1% | 60.3% | Muse Spark 1.2 |
GeneralLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Muse Spark 1.2 | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench data analysis | 76.5% | 60.2% | Muse Spark 1.2 |
| Public Benefits Bench (Vals AI) | 68.5% | Not measured | Only Muse Spark 1.2 measured |
| SAGE (Vals AI) | 47.7% | Not measured | Only Muse Spark 1.2 measured |
| MedScribe (Vals AI) | 90.1% | Not measured | Only Muse Spark 1.2 measured |
| Vals Multimodal Index | 69.8% | Not measured | Only Muse Spark 1.2 measured |
| Long context reasoning (AA-LCR) | 79.0% | 78.3% | Muse Spark 1.2 |
| DTBench | 94.7% | Not measured | Only Muse Spark 1.2 measured |
| LMCA | 48.4% | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text | 1482 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: instruction following | 1462 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: creative writing | 1436 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Vision | 1304 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: English | 1483 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: non-English | 1476 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: Chinese | 1509 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: Korean | 1462 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: French | 1495 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: Spanish | 1484 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: Russian | 1483 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: multi-turn | 1502 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: longer queries | 1473 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: writing and language | 1453 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Text: entertainment and media | 1443 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Vision: English | 1291 | Not measured | Only Muse Spark 1.2 measured |
| LMArena Vision: reading text | 1313 | Not measured | Only Muse Spark 1.2 measured |
| Neither model has a result on the other 21 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Muse Spark 1.2 | Muse Spark Open | Leader |
|---|---|---|---|
| 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
Same cost
Repository review
50K input + 3K output tokens
Same cost
Agent loop
200K input + 10K output tokens
Same cost
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.
| Specification | Meta Muse Spark 1.2 | Meta Muse Spark Open |
|---|---|---|
| Maker | Meta | Meta |
| Weights | No public weights listed | Open weights |
| Released | August 5, 2026 | October 15, 2026 |
| Context window | 1.05M | 1.05M |
| Input $/Mtok | $1.25 | $1.25 |
| Output $/Mtok | $4.25 | $4.25 |
| Coding index | 65.1 | 62.1 |
| Independent measurements behind it | 2 | 2 |
| Cost per solved task | $0.64 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Muse Spark 1.2 better than Muse Spark Open for coding?
Pick Muse Spark 1.2 for coding: it scores 65.1 on the Vibe Coding Index against 62.1 for Muse Spark Open. Pick Muse Spark Open when what matters is Terminal-Bench 4 (Vals AI) or SciCode, where it leads.
Which is cheaper, Muse Spark 1.2 or Muse Spark Open?
Muse Spark 1.2 costs $1.25 per million input tokens and $4.25 per million output tokens; Muse Spark Open costs $1.25 and $4.25. Cost per solved task is known for Muse Spark 1.2 only.
Which has the bigger context window, Muse Spark 1.2 or Muse Spark Open?
Neither: both take 1.05M tokens.
How many benchmarks is the Muse Spark 1.2 vs Muse Spark Open comparison based on?
25 benchmarks have a result for both models as of October 21, 2026. Muse Spark 1.2's coding index rests on 2 independent benchmarks and Muse Spark Open's on 2. Where only one model has a result, the page says so instead of naming a winner.