Claude Sonnet 5.5 vs Muse Spark Open
As of 18 Oct 2026, Claude Sonnet 5.5 (max) leads on quality (67.3 vs 61.2 on the BenchLeader Index), but Muse Spark Open (xhigh) costs 2.0× less, so it is the better buy unless you need the extra quality.
Claude Sonnet 5.5 
Muse Spark Open Key differences
- Claude Sonnet 5.5 (max) leads on quality: 67.3 vs 61.2.
- Claude Sonnet 5.5 (max) is stronger in agents & tools, coding, long context, maths, reasoning.
- Muse Spark Open (xhigh) is stronger in composite, knowledge, multimodal.
- Muse Spark Open (xhigh) is 2.0× cheaper ($2.00 vs $4.00 per 1M blended).
Choose Claude Sonnet 5.5 (max) if
- reasoning is the priority (81 vs 66 on the category score)
- long context is the priority (66 vs 64 on the category score)
Choose Muse Spark Open (xhigh) if
- knowledge is the priority (73 vs 65 on the category score)
- cost matters: $2.00 against $4.00 per million tokens blended
- the wait for the first word matters: 15.0 s against 380.3 s to first answer
- you want to run it yourself: its weights are open
Category by category
Category scores on the BenchLeader scale: 50 is the average evaluated model, 15 points is one standard deviation. A gap under one point is called level.
| Category | Claude Sonnet 5.5 (max) | Muse Spark Open (xhigh) | Leader |
|---|---|---|---|
| Reasoning | 80.6 | 65.5 | Claude Sonnet 5.5 |
| Coding | 69.3 | – | not comparable |
| Agents & tools | 69.6 | – | not comparable |
| Maths | 72.4 | – | not comparable |
| Knowledge | 65.0 | 72.5 | Muse Spark Open |
| Multimodal | – | 64.1 | not comparable |
| Long context | 66.4 | 64.2 | Claude Sonnet 5.5 |
| Composite | 71.9 | 73.1 | Muse Spark Open |
Price, speed and latency
List prices blended at three input tokens per output token. Per-task prices use the token counts on the methodology page; suite cost is what Artificial Analysis paid to run its whole Intelligence Index.
| Measure | Claude Sonnet 5.5 (max) | Muse Spark Open (xhigh) |
|---|---|---|
| Blended price per 1M tokens | $4.00 | $2.00 |
| Input / output per 1M | $2.00 / $10.00 | $1.25 / $4.25 |
| Price per task: chat reply | $0.0038 | $0.0018 |
| Price per task: summarise a 30-page report | $0.030 | $0.018 |
| Price per task: code edit | $0.027 | $0.014 |
| Price per task: agentic coding session | $0.160 | $0.092 |
| Price per task: structured extraction | $0.0060 | $0.0034 |
| Cost to run a full benchmark suite | $5.46 | $0.844 |
| Output speed | 140 tok/s | 140 tok/s |
| Time to first answer | 380.3 s | 15.0 s |
| Time to a complete answer | 383.9 s | 18.6 s |
Every benchmark
| Metric | Claude Sonnet 5.5 (max) | Muse Spark Open (xhigh) |
|---|---|---|
| BenchLeader Index | 67.3 | 61.2 |
| Agents & tools score | 69.6 | – |
| Coding score | 69.3 | – |
| Composite score | 71.9 | 73.1 |
| Knowledge score | 65.0 | 72.5 |
| Long context score | 66.4 | 64.2 |
| Maths score | 72.4 | – |
| Reasoning score | 80.6 | 65.5 |
| Multimodal score | – | 64.1 |
| Blended price $/M | $4.00 | $2.00 |
| Output speed | 140 tok/s | 140 tok/s |
| Time to first answer | 380.3 s | 15.0 s |
| Context window | 1M | 1.0M |
| GPQA Diamond | 95.6% | – |
| FrontierMath Tiers 1–3 | 88.8% | – |
| FrontierMath Tier 4 | 80.5% | – |
| OTIS Mock AIME | 100.0% | – |
| SimpleQA Verified | 46.5% | – |
| Terminal-Bench | 61.8% | – |
| SciCode | 61.0% | – |
| APEX-Agents | 75.5% | – |
| ProofBench | 100.0% | – |
| Arena Agent | 13 | – |
| LiveBench | 75.7% | – |
| LiveBench Reasoning | 91.6% | – |
| LiveBench Coding | 91.4% | – |
| LiveBench Agentic Coding | 56.3% | – |
| LiveBench Mathematics | 96.1% | – |
| LiveBench Data Analysis | 59.5% | – |
| LiveBench Language | 78.0% | – |
| LiveBench Instruction Following | 56.8% | – |
| AA Intelligence Index v4.3.2 | 56 | 38.9 |
| AA-LCR | 82.7% | 78.3% |
| MMMU-Pro | – | 80.9% |
| AA-Omniscience | 32.3 | 24.6 |
| GPQA Diamond (AA) | – | 89.0% |
| Humanity's Last Exam (AA) | 55.0% | 43.9% |
| SciCode (AA) | 61.0% | 58.5% |
| Vals Index | – | 46.6 |
| CritPt | 31.4% | 14.9% |
| GDPval-AA v2.1 | 66.9% | 45.1% |
| Analyst Agent (AA) | 57.5% | – |
| Code Migration | – | 21.2% |
| Excel Modeling Benchmark | – | 53.7% |
| Finance Agent v2 | – | 61.3% |
| Harvey's Legal Agent Benchmark | – | 16.7% |
| Legal Research Bench | – | 38.5% |
| Tax Agent Bench | – | 26.3% |
| Terminal-Bench 4.0 (Vals) | – | 6.6% |
| Vibe Code Bench v1.1 | – | 76.2% |
| Chess Puzzles | 59.0% | – |
| Mystery Game Puzzles | 65.0% | – |
| CursorBench | 55.5% | – |
| GDP.pdf | 31.4% | – |
| FrontierSWE | 61.9% | – |
| Terminal-Bench 4.0 (AA) | 63.6% | 8.1% |
| Terminal-Bench 2.1 (AA) | – | 76.4% |
| AutomationBench | 71.8% | 49.7% |
| GDP.pdf | 25.8% | 18.6% |
| MLCR | 75.0% | – |
| Harvey LAB-AA v1.1 | 2.8% | – |
| AA-Omniscience: accuracy | 54.0% | 39.3% |
| AA-Omniscience: non-hallucination | 53.0% | 75.9% |
| AA-Briefcase v1.1 | 1817 | 1279 |
| FrontierCode 1.1 (AA) | 45.8% | – |
| Terminal-Bench-Science 0.1 (AA) | 53.3% | – |
| AA-3D | 1197 | – |
| AA Openness Index | – | 27.8 |
Data as of 2026-10-18. Best configuration of each model; every score links to its source on the model pages.
Claude Sonnet 5.5 vs Muse Spark Open: questions
- Is Claude Sonnet 5.5 better than Muse Spark Open?
- Claude Sonnet 5.5 (max) leads on quality: 67.3 vs 61.2. The BenchLeader Index combines every independent quality benchmark; Claude Sonnet 5.5 (max) is ahead overall as of 2026-10-18, but check the category scores for your use.
- Which is cheaper, Claude Sonnet 5.5 or Muse Spark Open?
- Muse Spark Open is cheaper: $2.00 against $4.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Sonnet 5.5 or Muse Spark Open?
- Muse Spark Open streams faster: 140 against 140 output tokens per second.
- Which has the larger context window?
- Muse Spark Open accepts more context: 1.0M against 1M tokens.