# Claude Mythos 5.1 vs GPT-6.1 Terra

> Side-by-side benchmark comparison for Claude Mythos 5.1 and GPT-6.1 Terra across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-mythos-5-1-vs-gpt-6-1-terra
- Last updated: October 26, 2026

- Shared sourced benchmarks: 1
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Evidence is too thin for a benchmark verdict: Claude Mythos 5.1 and GPT-6.1 Terra share only 1 sourced benchmark row.

## Summary

- Only 1 shared sourced benchmark row is available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- Claude Mythos 5.1 has the lower published output-token price.
- GPT-6.1 Terra has the larger published context window at 1.05M.

## Model Snapshot

| Property | Claude Mythos 5.1 | GPT-6.1 Terra |
|----------|----------|----------|
| Creator | Anthropic | OpenAI |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1.05M |
| Independent public score (not head-to-head) | null | 75.87 |
| Benchmarks Covered | 1 | 10 |
| Pricing (input/output) | Pricing unavailable / Pricing unavailable | $1.00 / $5.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Claude Mythos 5.1 public-lane score: Coming soon
- GPT-6.1 Terra public-lane score: 72.4 (Estimated · #8/133)

| Benchmark | Claude Mythos 5.1 | GPT-6.1 Terra | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 4.0 | 60.90% | 50.30% | Claude Mythos 5.1 |
| Terminal-Bench-Science 0.1 | Coming soon | 58.3% | Coming soon |
| Agents' Last Exam | Coming soon | 60.0% | Coming soon |
| OSWorld 2.1 Offline | Coming soon | 74.2% | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Claude Mythos 5.1 public-lane score: Coming soon
- GPT-6.1 Terra public-lane score: 81.8 (Unranked · 2 rankable rows)

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Claude Mythos 5.1 public-lane score: Coming soon
- GPT-6.1 Terra public-lane score: 91.6 (#4/58)

| Benchmark | Claude Mythos 5.1 | GPT-6.1 Terra | Winner |
|-----------|-----------|-----------|--------|
| MMMU-Pro | Coming soon | 85.5% | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- Claude Mythos 5.1 public-lane score: Coming soon
- GPT-6.1 Terra public-lane score: 74.9 (Supported · #12/188)

| Benchmark | Claude Mythos 5.1 | GPT-6.1 Terra | Winner |
|-----------|-----------|-----------|--------|
| HealthBench (raw) | Coming soon | 51.1% | Coming soon |
| HealthBench (length-adjusted) | Coming soon | 55.1% | Coming soon |
| HealthBench Professional | Coming soon | 62.7% | Coming soon |
| HealthBench Professional (raw) | Coming soon | 64.2% | Coming soon |
| HealthBench Hard | Coming soon | 31.4% | Coming soon |

## FAQ

### Is there enough evidence to pick between Claude Mythos 5.1 and GPT-6.1 Terra?

Not yet. The models share only 1 sourced benchmark row, 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

- [Claude Mythos 5.1 vs Claude Mythos 5](/compare/claude-mythos-5-vs-claude-mythos-5-1)
- [GPT-6.1 Terra vs Claude Mythos 5](/compare/claude-mythos-5-vs-gpt-6-1-terra)
- [Claude Mythos 5.1 vs Claude Mythos Preview](/compare/claude-mythos-5-1-vs-claude-mythos-preview)
- [GPT-6.1 Terra vs Claude Mythos Preview](/compare/claude-mythos-preview-vs-gpt-6-1-terra)

## Explore More

- [Claude Mythos 5.1 profile](/models/claude-mythos-5-1)
- [GPT-6.1 Terra profile](/models/gpt-6-1-terra)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)