# Claude Mythos 5 vs GPT-5.6 Terra

> Side-by-side benchmark comparison for Claude Mythos 5 and GPT-5.6 Terra across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-mythos-5-vs-gpt-5-6-terra
- Last updated: September 24, 2026

- Shared sourced benchmarks: 6
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.7

## Quick Verdict

Pick Claude Mythos 5 if you want the stronger benchmark profile. GPT-5.6 Terra only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- Claude Mythos 5 leads overall 82 to 72.58.
- The clearest category separation is in multimodal & grounded, where the averages are 85.1 for Claude Mythos 5 and 77.2 for GPT-5.6 Terra.
- The biggest single benchmark swing is SWE-bench Pro in Coding, with scores of 80.3% and 63.4%.
- GPT-5.6 Terra is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- GPT-5.6 Terra also has the larger context window at 1.05M.

## Model Snapshot

| Property | Claude Mythos 5 | GPT-5.6 Terra |
|----------|----------|----------|
| Creator | Anthropic | OpenAI |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M+ | 1.05M |
| Overall Score | null | 72.58 |
| Benchmarks Covered | 15 | 32 |
| Pricing (input/output) | $10.00 / $50.00 | $2.00 / $12.00 |

## Category Breakdown

### Agentic

- Winner: Not comparable
- Claude Mythos 5 public-lane score: Coming soon
- GPT-5.6 Terra public-lane score: 59.5 (Supported · #18/105)

| Benchmark | Claude Mythos 5 | GPT-5.6 Terra | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 88.0% | 87.4% | Claude Mythos 5 |
| OSWorld-Verified | 85% | Coming soon | Coming soon |
| BrowseComp | 88% | 87.5% | Claude Mythos 5 |
| CyberGym | 83.8% | 81.8% | Claude Mythos 5 |
| Terminal-Bench 3.0 | Coming soon | 20.8% | Coming soon |
| OSWorld 2.0 | Coming soon | 50.2% | Coming soon |
| ExploitGym | Coming soon | 23.2% | Coming soon |
| Toolathlon | Coming soon | 53.1% | Coming soon |
| Terminal-Bench 2.1 (Vals) | Coming soon | 77.5% | Coming soon |
| ApprenticeBench | Coming soon | 16% | Coming soon |

### Coding

- Winner: Not comparable
- Claude Mythos 5 public-lane score: Coming soon
- GPT-5.6 Terra public-lane score: 64.7 (Supported · #8/135)

| Benchmark | Claude Mythos 5 | GPT-5.6 Terra | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 95.5% | Coming soon | Coming soon |
| SWE-bench Pro | 80.3% | 63.4% | Claude Mythos 5 |
| Terminal-Bench 2.1 | 88.0% | 87.4% | Claude Mythos 5 |
| DeepSWE | Coming soon | 69.6% | Coming soon |
| FrontierCode 1.1 Extended | Coming soon | 55.8% | Coming soon |
| cursorBench32 | Coming soon | 64.9% | Coming soon |
| VulcanBench v3 | Coming soon | 87.0% | Coming soon |
| LiveCodeBench (Vals) | Coming soon | 85.9% | Coming soon |
| SWE-bench (Vals) | Coming soon | 95.4% | Coming soon |

### Reasoning

- Winner: Not comparable
- Claude Mythos 5 public-lane score: Coming soon
- GPT-5.6 Terra public-lane score: 65.4 (#12/19)

| Benchmark | Claude Mythos 5 | GPT-5.6 Terra | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-2 | Coming soon | 83.9% | Coming soon |
| ARC-AGI-3 | Coming soon | 0.8% | Coming soon |

### Multimodal & Grounded

- Winner: Not comparable
- Claude Mythos 5 public-lane score: 85.1 (Unranked · 3 rankable rows)
- GPT-5.6 Terra public-lane score: 77.2 (#16/50)

| Benchmark | Claude Mythos 5 | GPT-5.6 Terra | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Multimodal | 54.9% | Coming soon | Coming soon |
| CharXiv | 93.5% | Coming soon | Coming soon |
| CharXiv w/o tools | 88.9% | Coming soon | Coming soon |
| MMMU-Pro | Coming soon | 80.7% | Coming soon |
| MMMU-Pro w/ Python | Coming soon | 82% | Coming soon |

### Knowledge

- Winner: Not comparable
- Claude Mythos 5 public-lane score: Coming soon
- GPT-5.6 Terra public-lane score: 71.1 (Supported · #9/158)

| Benchmark | Claude Mythos 5 | GPT-5.6 Terra | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 94.1% | 92.9% | Claude Mythos 5 |
| HLE | 64.5% | Coming soon | Coming soon |
| HLE w/o tools | 59% | Coming soon | Coming soon |
| GPQA-D | Coming soon | 92.9% | Coming soon |
| HLE-Verified | Coming soon | 51.1% | Coming soon |
| LABBench2 | Coming soon | 81.2% | Coming soon |
| HealthBench Professional | Coming soon | 57.7% | Coming soon |
| HealthBench Hard | Coming soon | 32.7% | Coming soon |
| GPQA Diamond (Vals) | Coming soon | 90.9% | Coming soon |
| MMLU-Pro (Vals) | Coming soon | 86.7% | Coming soon |

### Multilingual

- Winner: Not comparable
- Claude Mythos 5 public-lane score: Coming soon
- GPT-5.6 Terra public-lane score: Coming soon

| Benchmark | Claude Mythos 5 | GPT-5.6 Terra | Winner |
|-----------|-----------|-----------|--------|
| SWE Multilingual | 92.2% | Coming soon | Coming soon |

### Instruction Following

- Winner: Not comparable
- Claude Mythos 5 public-lane score: Coming soon
- GPT-5.6 Terra public-lane score: 85.7 (#35/124)

### Mathematics

- Winner: Not comparable
- Claude Mythos 5 public-lane score: Coming soon
- GPT-5.6 Terra public-lane score: 96.8 (Unranked · 3 rankable rows)

| Benchmark | Claude Mythos 5 | GPT-5.6 Terra | Winner |
|-----------|-----------|-----------|--------|
| USAMO 2026 | 97.6% | Coming soon | Coming soon |
| FrontierMath (legacy) | Coming soon | 84.9% | Coming soon |
| FrontierMath v2 (Tiers 1-3) | Coming soon | 84.900% | Coming soon |
| FrontierMath v2 (Tier 4) | Coming soon | 68.300% | Coming soon |

## FAQ

### Which is better overall, Claude Mythos 5 or GPT-5.6 Terra?

Claude Mythos 5 is ahead overall on BenchLM right now.

### Where is the biggest gap between Claude Mythos 5 and GPT-5.6 Terra?

The widest category gap is in multimodal & grounded, where the averages are 85.1 for Claude Mythos 5 and 77.2 for GPT-5.6 Terra.

### How many benchmarks does Claude Mythos 5 cover on BenchLM?

Claude Mythos 5 currently has 15 sourced benchmark scores on BenchLM.

### How many benchmarks does GPT-5.6 Terra cover on BenchLM?

GPT-5.6 Terra currently has 32 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Claude Mythos 5 vs Claude Mythos 5.1](/compare/claude-mythos-5-vs-claude-mythos-5-1)
- [GPT-5.6 Terra vs Claude Mythos 5.1](/compare/claude-mythos-5-1-vs-gpt-5-6-terra)
- [Claude Mythos 5 vs Claude Mythos Preview](/compare/claude-mythos-5-vs-claude-mythos-preview)
- [GPT-5.6 Terra vs Claude Mythos Preview](/compare/claude-mythos-preview-vs-gpt-5-6-terra)

## Explore More

- [Claude Mythos 5 profile](/models/claude-mythos-5)
- [GPT-5.6 Terra profile](/models/gpt-5-6-terra)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)