Claude Sonnet 5 vs Muse Spark Open
Updated October 21, 2026. 26 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Claude Sonnet 5 and Muse Spark Open are level for coding, 63.5 against 62.1 on the Vibe Coding Index, so price and context decide.
Pick Muse Spark Open when output tokens cost 2.4x less, or when the context window is larger, 1.05M against 1M tokens. Pick Claude Sonnet 5 when what matters is LiveBench coding or LMArena WebDev, where it leads.
- Shared results
- 26
- Claude Sonnet 5 only
- 94
- Muse Spark Open only
- 0
- 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
No call
Level: 63.5 against 62.1, inside 2 points.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
No call
Only Claude Sonnet 5 has a AA Intelligence Index result, 38.2.
Directional only
Agentic work
AA Agentic Index
No call
Only Claude Sonnet 5 has a AA Agentic Index result, 43.6.
Directional only
Reasoning
GPQA Diamond
No call
Only Claude Sonnet 5 has a GPQA Diamond result, 88.9%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Sonnet 5 has a MMLU Pro result, 87.5%.
Directional only
Web design
Design Arena: websites
Muse Spark Open
Muse Spark Open leads, 1311 against 1274.
Same board, both measured
Long documents
Listed context window
Muse Spark Open
Muse Spark Open takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Muse Spark Open
Claude Sonnet 5 $0.0070, Muse Spark Open $0.0034 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Claude Sonnet 5 has the number, $1.87.
Directional only
At a glance
- Coding index
- Claude Sonnet 5 63.5 from 2 benchmarks, Muse Spark Open 62.1 from 2 benchmarks.
- Widest category
- Agentic work, 13.3 points apart on average over 8 shared benchmarks.
- Widest single gap
- LiveBench browser: Claude Sonnet 5 72.0% against Muse Spark Open 36.0%, 36.0 points apart on a 0 to 100 scale.
- Output price
- Claude Sonnet 5 $10.00 against Muse Spark Open $4.25 per million output tokens, 2.4x apart.
- Context window
- Claude Sonnet 5 takes 1M tokens, Muse Spark Open 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.
| Category | Claude Sonnet 5 | Bars | Muse Spark Open | Ties |
|---|---|---|---|---|
| Coding | 7 | 2 | ||
| Intelligence | 1 | 0 | ||
| Agentic work | 7 | 1 | ||
| Reasoning | 2 | 1 | ||
| Web design | 1 | 2 | ||
| General | 2 | 0 | ||
| All shared boards | 20 | 6 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index72
| Benchmark | Claude Sonnet 5 | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench coding | 74.7% | 73.6% | Claude Sonnet 5 |
| LMArena WebDev | 1540 | 1528 | Claude Sonnet 5 |
| AA Coding Index | 71.5 | Not measured | Only Claude Sonnet 5 measured |
| LiveCodeBench (Vals AI) | 82.4% | Not measured | Only Claude Sonnet 5 measured |
| SWE-bench Verified (Vals AI) | 79.6% | Not measured | Only Claude Sonnet 5 measured |
| Terminal-Bench 4 (Vals AI) | 10.6% | 6.6% | Claude Sonnet 5 |
| Vibe Code Bench (Vals AI) | 81.3% | 76.2% | Claude Sonnet 5 |
| Code migration (Vals AI) | 44.4% | 21.2% | Claude Sonnet 5 |
| ProgramBench (Vals AI) | 0.0% | Not measured | Only Claude Sonnet 5 measured |
| IOI (Vals AI) | 45.0% | Not measured | Only Claude Sonnet 5 measured |
| Terminal-Bench 2.1 (Vals AI) | 74.5% | Not measured | Only Claude Sonnet 5 measured |
| Vibe Code Bench 1-100 (Vals AI) | 13.8% | Not measured | Only Claude Sonnet 5 measured |
| SkillsBench (Vals AI) | 46.5% | Not measured | Only Claude Sonnet 5 measured |
| CyberBench (Vals AI) | 70.3% | Not measured | Only Claude Sonnet 5 measured |
| SciCode | 54.3% | 58.4% | Muse Spark Open |
| FrontierCode | 42.7% | Not measured | Only Claude Sonnet 5 measured |
| GSO-Bench | 37.3% | Not measured | Only Claude Sonnet 5 measured |
| WeirdML | 68.8% | Not measured | Only Claude Sonnet 5 measured |
| ALE-Bench | 1463.1 | 1590.1 | Muse Spark Open |
| LMArena Text: coding | 1483 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: software and IT | 1474 | Not measured | Only Claude Sonnet 5 measured |
| LMArena WebDev: React | 1541 | 1529 | Claude Sonnet 5 |
| LMArena WebDev: HTML | 1527 | 1495 | Claude Sonnet 5 |
| LMArena WebDev: from an image | 1540 | Not measured | Only Claude Sonnet 5 measured |
| Neither model has a result on the other 14 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Sonnet 5 | Muse Spark Open | Leader |
|---|---|---|---|
| AA Intelligence Index | 38.2 | Not measured | Only Claude Sonnet 5 measured |
| Epoch Capabilities Index | 156.9 | 155.1 | Claude Sonnet 5 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index71
| Benchmark | Claude Sonnet 5 | Muse Spark Open | Leader |
|---|---|---|---|
| AA Agentic Index | 43.6 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: agents building web apps | 1245 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: agents building full-stack apps | 1249 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: agents building mobile apps | 1215 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: agents building Android apps | 1231 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: agents building Godot games | 1225 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: agents building games | 1227 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: HTML slides | 1218 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: PowerPoint slides | 1216 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: spreadsheets | 1004 | Not measured | Only Claude Sonnet 5 measured |
| LiveBench research | 82.8% | 80.3% | Claude Sonnet 5 |
| LiveBench browser | 72.0% | 36.0% | Claude Sonnet 5 |
| LiveBench long agentic | 39.0% | 18.9% | Claude Sonnet 5 |
| SREBench (Vals AI) | 0.4% | Not measured | Only Claude Sonnet 5 measured |
| Finance Agent (Vals AI) | 53.9% | 61.3% | Muse Spark Open |
| Tax Agent Bench (Vals AI) | 29.4% | 26.3% | Claude Sonnet 5 |
| Legal Research Bench (Vals AI) | 41.8% | 38.5% | Claude Sonnet 5 |
| Excel Modeling Benchmark (Vals AI) | 66.3% | 53.7% | Claude Sonnet 5 |
| Terminal-Bench-Science (Vals AI) | 5.7% | Not measured | Only Claude Sonnet 5 measured |
| APEX-Agents | 54.5% | 33.4% | Claude Sonnet 5 |
| Vending-Bench 2 | $6,378 | Not measured | Only Claude Sonnet 5 measured |
| Neither model has a result on the other 18 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index21
| Benchmark | Claude Sonnet 5 | Muse Spark Open | Leader |
|---|---|---|---|
| GPQA Diamond | 88.9% | Not measured | Only Claude Sonnet 5 measured |
| LiveBench reasoning | 88.7% | 73.7% | Claude Sonnet 5 |
| MMMU Pro (Vals AI) | 83.0% | Not measured | Only Claude Sonnet 5 measured |
| GPQA Diamond (Artificial Analysis run) | 91.1% | 89.0% | Claude Sonnet 5 |
| Humanity's Last Exam (Artificial Analysis run) | 41.3% | 43.9% | Muse Spark Open |
| GPQA Diamond (Epoch AI run) | 90.5% | Not measured | Only Claude Sonnet 5 measured |
| SimpleBench | 60.6% | Not measured | Only Claude Sonnet 5 measured |
| Chess puzzles | 45.0% | Not measured | Only Claude Sonnet 5 measured |
| Mystery game puzzles | 35.0% | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: hard prompts | 1461 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: expert | 1489 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: hard prompts in English | 1464 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Vision: diagrams | 1293 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Vision: homework | 1311 | Not measured | Only Claude Sonnet 5 measured |
| Neither model has a result on the other 7 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index6 boards, none shared
| Benchmark | Claude Sonnet 5 | Muse Spark Open | Leader |
|---|---|---|---|
| OTIS Mock AIME | 94.7% | Not measured | Only Claude Sonnet 5 measured |
| FrontierMath, tiers 1 to 3 | 65.6% | Not measured | Only Claude Sonnet 5 measured |
| FrontierMath, tier 4 | 29.3% | Not measured | Only Claude Sonnet 5 measured |
| ProofBench | 77.0% | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: math | 1467 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: mathematical work | 1481 | Not measured | Only Claude Sonnet 5 measured |
| Neither model has a result on the other 7 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index11 boards, none shared
| Benchmark | Claude Sonnet 5 | Muse Spark Open | Leader |
|---|---|---|---|
| MMLU Pro | 87.5% | Not measured | Only Claude Sonnet 5 measured |
| LegalBench (Vals AI) | 83.9% | Not measured | Only Claude Sonnet 5 measured |
| CorpFin (Vals AI) | 67.0% | Not measured | Only Claude Sonnet 5 measured |
| TaxEval (Vals AI) | 75.6% | Not measured | Only Claude Sonnet 5 measured |
| MortgageTax (Vals AI) | 70.0% | Not measured | Only Claude Sonnet 5 measured |
| MedCode (Vals AI) | 47.5% | Not measured | Only Claude Sonnet 5 measured |
| SimpleQA Verified | 33.7% | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: science | 1460 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: medicine and healthcare | 1442 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: legal and government | 1454 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: business and finance | 1436 | Not measured | Only Claude Sonnet 5 measured |
| Neither model has a result on the other 6 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index12
| Benchmark | Claude Sonnet 5 | Muse Spark Open | Leader |
|---|---|---|---|
| Design Arena: websites | 1274 | 1311 | Muse Spark Open |
| Design Arena: UI components | 1279 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: game dev | 1278 | 1290 | Muse Spark Open |
| Design Arena: data viz | 1251 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: 3D | 1261 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: all code categories | 1276 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: SVG | 1193 | Not measured | Only Claude Sonnet 5 measured |
| Design Arena: ASCII art | 1207 | Not measured | Only Claude Sonnet 5 measured |
| LiveBench design | 82.0% | 60.3% | Claude Sonnet 5 |
GeneralLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Sonnet 5 | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench data analysis | 71.7% | 60.2% | Claude Sonnet 5 |
| Public Benefits Bench (Vals AI) | 66.0% | Not measured | Only Claude Sonnet 5 measured |
| SAGE (Vals AI) | 48.9% | Not measured | Only Claude Sonnet 5 measured |
| MedScribe (Vals AI) | 76.0% | Not measured | Only Claude Sonnet 5 measured |
| Vals Multimodal Index | 68.8% | Not measured | Only Claude Sonnet 5 measured |
| Long context reasoning (AA-LCR) | 82.0% | 78.3% | Claude Sonnet 5 |
| DTBench | 92.5% | Not measured | Only Claude Sonnet 5 measured |
| LMCA | 50.0% | Not measured | Only Claude Sonnet 5 measured |
| Surface Evolver Bench | 60.0% | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text | 1442 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: instruction following | 1452 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: creative writing | 1416 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Vision | 1273 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: English | 1450 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: non-English | 1431 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: Chinese | 1478 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: German | 1442 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: Japanese | 1422 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: Korean | 1412 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: French | 1463 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: Spanish | 1438 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: Russian | 1450 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: Polish | 1425 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: multi-turn | 1453 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: longer queries | 1462 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: writing and language | 1436 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Text: entertainment and media | 1411 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Vision: English | 1275 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Vision: Chinese | 1331 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Vision: reading text | 1288 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Vision: humor | 1261 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Vision: creative writing | 1246 | Not measured | Only Claude Sonnet 5 measured |
| LMArena Document | 1466 | Not measured | Only Claude Sonnet 5 measured |
| Neither model has a result on the other 13 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Sonnet 5 | 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
Muse Spark Open costs less
Repository review
50K input + 3K output tokens
Muse Spark Open costs less
Agent loop
200K input + 10K output tokens
Muse Spark Open 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.
| Specification | Anthropic Claude Sonnet 5 | Meta Muse Spark Open |
|---|---|---|
| Maker | Anthropic | Meta |
| Weights | No public weights listed | Open weights |
| Released | June 30, 2026 | October 15, 2026 |
| Context window | 1M | 1.05M |
| Input $/Mtok | $2.00 | $1.25 |
| Output $/Mtok | $10.00 | $4.25 |
| Coding index | 63.5 | 62.1 |
| Independent measurements behind it | 2 | 2 |
| Cost per solved task | $1.87 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Sonnet 5 better than Muse Spark Open for coding?
Claude Sonnet 5 and Muse Spark Open are level for coding, 63.5 against 62.1 on the Vibe Coding Index, so price and context decide. Pick Muse Spark Open when output tokens cost 2.4x less, or when the context window is larger, 1.05M against 1M tokens. Pick Claude Sonnet 5 when what matters is LiveBench coding or LMArena WebDev, where it leads.
Which is cheaper, Claude Sonnet 5 or Muse Spark Open?
Claude Sonnet 5 costs $2.00 per million input tokens and $10.00 per million output tokens; Muse Spark Open costs $1.25 and $4.25. Cost per solved task is known for Claude Sonnet 5 only.
Which has the bigger context window, Claude Sonnet 5 or Muse Spark Open?
Muse Spark Open, with 1.05M tokens against 1M.
How many benchmarks is the Claude Sonnet 5 vs Muse Spark Open comparison based on?
26 benchmarks have a result for both models as of October 21, 2026. Claude Sonnet 5'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.