Claude Haiku 5.5 vs Muse Spark Open
Updated October 21, 2026. 24 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Pick Claude Haiku 5.5 for coding: it scores 75.9 on the Vibe Coding Index against 62.1 for Muse Spark Open.
Pick Muse Spark Open when the context window is larger, 1.05M against 1M tokens, or when what matters is SciCode or Finance Agent (Vals AI), where it leads.
- Shared results
- 24
- Claude Haiku 5.5 only
- 38
- Muse Spark Open only
- 2
- 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
Claude Haiku 5.5
Claude Haiku 5.5 scores 75.9 against 62.1.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
No call
Only Claude Haiku 5.5 has a AA Intelligence Index result, 43.4.
Directional only
Web design
Design Arena: websites
Muse Spark Open
Muse Spark Open leads, 1311 against 1263.
Same board, both measured
General
Vals Index
No call
Only Claude Haiku 5.5 has a Vals Index result, 58.7%.
Directional only
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
Claude Haiku 5.5
Claude Haiku 5.5 $0.0003, Muse Spark Open $0.0034 per turn.
List prices
At a glance
- Coding index
- Claude Haiku 5.5 75.9 from 2 benchmarks, Muse Spark Open 62.1 from 2 benchmarks.
- Widest category
- Agentic work, 16.2 points apart on average over 8 shared benchmarks.
- Widest single gap
- LiveBench browser: Claude Haiku 5.5 80.0% against Muse Spark Open 36.0%, 44.0 points apart on a 0 to 100 scale.
- Output price
- Claude Haiku 5.5 $0.50 against Muse Spark Open $4.25 per million output tokens, 8.5x apart.
- Context window
- Claude Haiku 5.5 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 Haiku 5.5 | Bars | Muse Spark Open | Ties |
|---|---|---|---|---|
| Coding | 7 | 1 | ||
| Intelligence | 1 | 0 | ||
| Agentic work | 7 | 1 | ||
| Reasoning | 2 | 0 | ||
| Web design | 2 | 1 | ||
| General | 1 | 1 | ||
| All shared boards | 20 | 4 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index71
| Benchmark | Claude Haiku 5.5 | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench coding | 91.4% | 73.6% | Claude Haiku 5.5 |
| LMArena WebDev | 1586 | 1528 | Claude Haiku 5.5 |
| Terminal-Bench 4 (Vals AI) | 36.4% | 6.6% | Claude Haiku 5.5 |
| Vibe Code Bench (Vals AI) | 90.4% | 76.2% | Claude Haiku 5.5 |
| Code migration (Vals AI) | 44.6% | 21.2% | Claude Haiku 5.5 |
| ProgramBench (Vals AI) | 2.5% | Not measured | Only Claude Haiku 5.5 measured |
| IOI (Vals AI) | 47.3% | Not measured | Only Claude Haiku 5.5 measured |
| SWE-bench Multimodal (Vals AI) | 44.0% | Not measured | Only Claude Haiku 5.5 measured |
| Vibe Code Bench 1-100 (Vals AI) | 20.4% | Not measured | Only Claude Haiku 5.5 measured |
| CyberBench (Vals AI) | 75.5% | Not measured | Only Claude Haiku 5.5 measured |
| SciCode | 55.0% | 58.4% | Muse Spark Open |
| FrontierCode | 46.4% | Not measured | Only Claude Haiku 5.5 measured |
| FrontierSWE | 43.8% | Not measured | Only Claude Haiku 5.5 measured |
| ALE-Bench | Not measured | 1590.1 | Only Muse Spark Open measured |
| LMArena WebDev: React | 1605 | 1529 | Claude Haiku 5.5 |
| LMArena WebDev: HTML | 1569 | 1495 | Claude Haiku 5.5 |
| Neither model has a result on the other 22 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Haiku 5.5 | Muse Spark Open | Leader |
|---|---|---|---|
| AA Intelligence Index | 43.4 | Not measured | Only Claude Haiku 5.5 measured |
| Epoch Capabilities Index | 159.3 | 155.1 | Claude Haiku 5.5 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index71
| Benchmark | Claude Haiku 5.5 | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench research | 81.9% | 80.3% | Claude Haiku 5.5 |
| LiveBench browser | 80.0% | 36.0% | Claude Haiku 5.5 |
| LiveBench long agentic | 57.6% | 18.9% | Claude Haiku 5.5 |
| SREBench (Vals AI) | 5.7% | Not measured | Only Claude Haiku 5.5 measured |
| Finance Agent (Vals AI) | 54.1% | 61.3% | Muse Spark Open |
| Tax Agent Bench (Vals AI) | 31.9% | 26.3% | Claude Haiku 5.5 |
| Legal Research Bench (Vals AI) | 43.3% | 38.5% | Claude Haiku 5.5 |
| Harvey's Legal Agent Benchmark (Vals AI) | 4.2% | Not measured | Only Claude Haiku 5.5 measured |
| Excel Modeling Benchmark (Vals AI) | 59.0% | 53.7% | Claude Haiku 5.5 |
| BioMysteryBench (Vals AI) | 70.4% | Not measured | Only Claude Haiku 5.5 measured |
| Terminal-Bench-Science (Vals AI) | 10.0% | Not measured | Only Claude Haiku 5.5 measured |
| Vals Science Index | 38.5% | Not measured | Only Claude Haiku 5.5 measured |
| APEX-Agents | 56.1% | 33.4% | Claude Haiku 5.5 |
| Vending-Bench 2 | $3,602 | Not measured | Only Claude Haiku 5.5 measured |
| Neither model has a result on the other 25 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Haiku 5.5 | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench reasoning | 82.4% | 73.7% | Claude Haiku 5.5 |
| MysteryMechanism (Vals AI) | 35.1% | Not measured | Only Claude Haiku 5.5 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 89.0% | Only Muse Spark Open measured |
| Humanity's Last Exam (Artificial Analysis run) | 44.4% | 43.9% | Claude Haiku 5.5 |
| GPQA Diamond (Epoch AI run) | 89.6% | Not measured | Only Claude Haiku 5.5 measured |
| ARC-AGI | 89.0% | Not measured | Only Claude Haiku 5.5 measured |
| ARC-AGI-2 | 61.3% | Not measured | Only Claude Haiku 5.5 measured |
| Chess puzzles | 55.0% | Not measured | Only Claude Haiku 5.5 measured |
| Mystery game puzzles | 30.0% | Not measured | Only Claude Haiku 5.5 measured |
| EBR-bench | 43.8% | Not measured | Only Claude Haiku 5.5 measured |
| Neither model has a result on the other 11 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index4 boards, none shared
| Benchmark | Claude Haiku 5.5 | Muse Spark Open | Leader |
|---|---|---|---|
| OTIS Mock AIME | 98.9% | Not measured | Only Claude Haiku 5.5 measured |
| FrontierMath, tiers 1 to 3 | 75.1% | Not measured | Only Claude Haiku 5.5 measured |
| FrontierMath, tier 4 | 46.3% | Not measured | Only Claude Haiku 5.5 measured |
| ProofBench | 89.0% | Not measured | Only Claude Haiku 5.5 measured |
| Neither model has a result on the other 9 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Claude Haiku 5.5 | Muse Spark Open | Leader |
|---|---|---|---|
| MedCode (Vals AI) | 51.5% | Not measured | Only Claude Haiku 5.5 measured |
| SimpleQA Verified | 23.8% | Not measured | Only Claude Haiku 5.5 measured |
| Neither model has a result on the other 15 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index21
| Benchmark | Claude Haiku 5.5 | Muse Spark Open | Leader |
|---|---|---|---|
| Design Arena: websites | 1263 | 1311 | Muse Spark Open |
| Design Arena: UI components | 1295 | Not measured | Only Claude Haiku 5.5 measured |
| Design Arena: game dev | 1315 | 1290 | Claude Haiku 5.5 |
| Design Arena: data viz | 1292 | Not measured | Only Claude Haiku 5.5 measured |
| Design Arena: 3D | 1343 | Not measured | Only Claude Haiku 5.5 measured |
| Design Arena: all code categories | 1279 | Not measured | Only Claude Haiku 5.5 measured |
| LiveBench design | 83.1% | 60.3% | Claude Haiku 5.5 |
| Neither model has a result on the other 2 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index11
| Benchmark | Claude Haiku 5.5 | Muse Spark Open | Leader |
|---|---|---|---|
| Vals Index | 58.7% | Not measured | Only Claude Haiku 5.5 measured |
| LiveBench data analysis | 53.1% | 60.2% | Muse Spark Open |
| Public Benefits Bench (Vals AI) | 63.2% | Not measured | Only Claude Haiku 5.5 measured |
| SAGE (Vals AI) | 45.8% | Not measured | Only Claude Haiku 5.5 measured |
| MedScribe (Vals AI) | 89.5% | Not measured | Only Claude Haiku 5.5 measured |
| Long context reasoning (AA-LCR) | 82.7% | 78.3% | Claude Haiku 5.5 |
| DTBench | 95.0% | Not measured | Only Claude Haiku 5.5 measured |
| LMCA | 51.1% | Not measured | Only Claude Haiku 5.5 measured |
| Furniture assembly | 47.5% | Not measured | Only Claude Haiku 5.5 measured |
| Neither model has a result on the other 37 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Haiku 5.5 | 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
Claude Haiku 5.5 costs less
Repository review
50K input + 3K output tokens
Claude Haiku 5.5 costs less
Agent loop
200K input + 10K output tokens
Claude Haiku 5.5 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 Haiku 5.5 | Meta Muse Spark Open |
|---|---|---|
| Maker | Anthropic | Meta |
| Weights | No public weights listed | Open weights |
| Released | October 7, 2026 | October 15, 2026 |
| Context window | 1M | 1.05M |
| Input $/Mtok | $0.10 | $1.25 |
| Output $/Mtok | $0.50 | $4.25 |
| Coding index | 75.9 | 62.1 |
| Independent measurements behind it | 2 | 2 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Haiku 5.5 better than Muse Spark Open for coding?
Pick Claude Haiku 5.5 for coding: it scores 75.9 on the Vibe Coding Index against 62.1 for Muse Spark Open. Pick Muse Spark Open when the context window is larger, 1.05M against 1M tokens, or when what matters is SciCode or Finance Agent (Vals AI), where it leads.
Which is cheaper, Claude Haiku 5.5 or Muse Spark Open?
Claude Haiku 5.5 costs $0.10 per million input tokens and $0.50 per million output tokens; Muse Spark Open costs $1.25 and $4.25. Cost per solved task is known for neither of them.
Which has the bigger context window, Claude Haiku 5.5 or Muse Spark Open?
Muse Spark Open, with 1.05M tokens against 1M.
How many benchmarks is the Claude Haiku 5.5 vs Muse Spark Open comparison based on?
24 benchmarks have a result for both models as of October 21, 2026. Claude Haiku 5.5'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.