# GPT-5.5 vs Muse Spark Open

> Side-by-side benchmark comparison for GPT-5.5 and Muse Spark Open across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-5-5-vs-muse-spark-open
- Last updated: October 15, 2026

- Shared sourced benchmarks: 2
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Evidence is too thin for a benchmark verdict: GPT-5.5 and Muse Spark Open share only 2 sourced benchmark rows.

## Summary

- Only 2 shared sourced benchmark rows are available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- Muse Spark Open has the lower published output-token price.

## Model Snapshot

| Property | GPT-5.5 | Muse Spark Open |
|----------|----------|----------|
| Creator | OpenAI | Meta |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1M |
| Independent public score (not head-to-head) | 69.35 | 62.66 |
| Benchmarks Covered | 42 | 7 |
| Pricing (input/output) | $5.00 / $30.00 | Pricing unavailable / Pricing unavailable |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- GPT-5.5 public-lane score: 62.8 (Supported · #22/127)
- Muse Spark Open public-lane score: 60.2 (Estimated · #27/127)

| Benchmark | GPT-5.5 | Muse Spark Open | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 82% | Coming soon | Coming soon |
| CyberGym | 81.8% | Coming soon | Coming soon |
| BrowseComp | 84.4% | Coming soon | Coming soon |
| OSWorld-Verified | 78.7% | Coming soon | Coming soon |
| MCP Atlas | 75.3% | 89.2% | Muse Spark Open |
| Toolathlon | 55.6% | Coming soon | Coming soon |
| τ²-bench results | 98% | Coming soon | Coming soon |
| Gert Labs | 72.93% | Coming soon | Coming soon |
| ResearchClawBench | 17.0% | Coming soon | Coming soon |
| OSWorld 2.0 | 13.0% | Coming soon | Coming soon |
| JobBench | 42.7% | 61.8% | Muse Spark Open |
| ExploitGym | 13.4% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 76.4% | Coming soon | Coming soon |
| ApprenticeBench | 20% | Coming soon | Coming soon |
| MazeBench | 0% | Coming soon | Coming soon |
| HLE w/ tools | Coming soon | 61.0% | Coming soon |
| Toolathlon-Verified | Coming soon | 72.8% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- GPT-5.5 public-lane score: 62 (Supported · #14/150)
- Muse Spark Open public-lane score: 56.1 (Supported · #29/150)

| Benchmark | GPT-5.5 | Muse Spark Open | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Pro | 58.6% | Coming soon | Coming soon |
| Terminal-Bench 2.0 | 82.0% | Coming soon | Coming soon |
| Vibe Code Bench | 69.85% | Coming soon | Coming soon |
| React Native Evals | 84.7% | Coming soon | Coming soon |
| cursorBench31 | 59.2% | Coming soon | Coming soon |
| CursorBench 3.2 | 58.4% | Coming soon | Coming soon |
| FrontierCode 1.1 Main | 43.0% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 85.3% | Coming soon | Coming soon |
| SWE-bench (Vals) | 82.6% | Coming soon | Coming soon |
| PostTrainBench v1.1 | 27.2% | Coming soon | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- GPT-5.5 public-lane score: 70.4 (#20/28)
- Muse Spark Open public-lane score: 79.6 (Unranked · 2 rankable rows)

| Benchmark | GPT-5.5 | Muse Spark Open | Winner |
|-----------|-----------|-----------|--------|
| MRCR v2 64K-128K | 83.1% | Coming soon | Coming soon |
| MRCR v2 128K-256K | 87.5% | Coming soon | Coming soon |
| ARC-AGI-2 | 85% | Coming soon | Coming soon |
| ARC-AGI-3 | 0.4% | Coming soon | Coming soon |
| ARC-AGI-1 | 95.00% | Coming soon | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- GPT-5.5 public-lane score: 75.5 (#23/54)
- Muse Spark Open public-lane score: 83.6 (Unranked · 4 rankable rows)

| Benchmark | GPT-5.5 | Muse Spark Open | Winner |
|-----------|-----------|-----------|--------|
| MMMU-Pro | 81.2% | Coming soon | Coming soon |
| MMMU-Pro w/ Python | 83.2% | Coming soon | Coming soon |
| OfficeQA Pro | 54.1% | Coming soon | Coming soon |
| ZeroBench | Coming soon | 50.0% | Coming soon |
| BabyVision | Coming soon | 80.2% | Coming soon |
| SimpleVQA | Coming soon | 73.6% | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- GPT-5.5 public-lane score: 72 (Supported · #14/184)
- Muse Spark Open public-lane score: 64.6 (Supported · #38/184)

| Benchmark | GPT-5.5 | Muse Spark Open | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 93.6% | Coming soon | Coming soon |
| GPQA-D | 93.6% | Coming soon | Coming soon |
| HLE | 52.2% | Coming soon | Coming soon |
| HLE w/o tools | 41.4% | Coming soon | Coming soon |
| GPQA Diamond (Vals) | 93.2% | Coming soon | Coming soon |
| MMLU-Pro (Vals) | 88.1% | Coming soon | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- GPT-5.5 public-lane score: 93.3 (#8/146)
- Muse Spark Open public-lane score: Coming soon

### Mathematics

- Winner: Insufficient shared evidence
- GPT-5.5 public-lane score: 91.2 (Unranked · 3 rankable rows)
- Muse Spark Open public-lane score: Coming soon

| Benchmark | GPT-5.5 | Muse Spark Open | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath (legacy) | 51.7% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 85.263% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 72.500% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between GPT-5.5 and Muse Spark Open?

Not yet. The models share only 2 sourced benchmark rows, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [GPT-5.5 vs GPT-5.5 Pro](/compare/gpt-5-5-vs-gpt-5-5-pro)
- [Muse Spark Open vs GPT-5.5 Pro](/compare/gpt-5-5-pro-vs-muse-spark-open)
- [GPT-5.5 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-gpt-5-5)
- [Muse Spark Open vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-muse-spark-open)

## Explore More

- [GPT-5.5 profile](/models/gpt-5-5)
- [Muse Spark Open profile](/models/muse-spark-open)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)