# Claude Opus 4.8 vs Mistral Medium 3.5 128B

> Side-by-side benchmark comparison for Claude Opus 4.8 and Mistral Medium 3.5 128B across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-opus-4-8-vs-mistral-medium-3-5-128b
- Last updated: October 10, 2026

- Shared sourced benchmarks: 6
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Claude Opus 4.8 leads by point estimate. Conditional score ranges do not establish rank confidence. Choose using the category evidence and your own workload tests.

## Summary

- Claude Opus 4.8 has the higher overall point estimate 69.12 to 34.72. Conditional score ranges do not establish rank confidence.
- The clearest category separation is in agentic, where the averages are 61.6 for Claude Opus 4.8 and 19.2 for Mistral Medium 3.5 128B.
- The biggest single benchmark swing is GPQA Diamond (Vals) in Knowledge, with scores of 92.4% and 34.8%.
- Mistral Medium 3.5 128B is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- Claude Opus 4.8 also has the larger context window at 1M.

## Model Snapshot

| Property | Claude Opus 4.8 | Mistral Medium 3.5 128B |
|----------|----------|----------|
| Creator | Anthropic | Mistral |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 256K |
| Overall Score | 69.12 | 34.72 |
| Benchmarks Covered | 40 | 7 |
| Pricing (input/output) | $5.00 / $25.00 | $1.50 / $7.50 |

## Category Breakdown

### Agentic

- Winner: Claude Opus 4.8
- Claude Opus 4.8 public-lane score: 61.6 (Supported · #20/123)
- Mistral Medium 3.5 128B public-lane score: 19.2 (Supported · #103/123)

| Benchmark | Claude Opus 4.8 | Mistral Medium 3.5 128B | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 3.0 | 21.1% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 74.6% | Coming soon | Coming soon |
| BrowseComp | 84.3% | Coming soon | Coming soon |
| DeepSearchQA | 93.1% | Coming soon | Coming soon |
| OSWorld-Verified | 83.4% | Coming soon | Coming soon |
| Finance Agent v2 | 53.9% | Coming soon | Coming soon |
| MCP Atlas | 82.2% | Coming soon | Coming soon |
| Toolathlon | 59.9% | Coming soon | Coming soon |
| Gert Labs | 72.97% | 39.10% | Claude Opus 4.8 |
| ResearchClawBench | 21.1% | Coming soon | Coming soon |
| OSWorld 2.0 | 20.6% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 71.9% | 39.0% | Claude Opus 4.8 |
| τ³-bench results | Coming soon | 91.4% | Coming soon |

### Coding

- Winner: Directional only
- Claude Opus 4.8 public-lane score: 60.8 (Supported · #19/146)
- Mistral Medium 3.5 128B public-lane score: 23.6 (Estimated · #110/146)

| Benchmark | Claude Opus 4.8 | Mistral Medium 3.5 128B | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 88.6% | 77.6% | Claude Opus 4.8 |
| SWE-bench Pro | 69.2% | Coming soon | Coming soon |
| SWE Multilingual | 84.4% | Coming soon | Coming soon |
| SWE Multimodal | 38.4% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 74.6% | Coming soon | Coming soon |
| cursorBench31 | 58.4% | Coming soon | Coming soon |
| CursorBench 3.2 | 62.3% | Coming soon | Coming soon |
| FrontierCode 1.1 Main | 46.5% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 87.8% | Coming soon | Coming soon |
| SWE-bench (Vals) | 88.6% | 66.4% | Claude Opus 4.8 |
| PostTrainBench v1.1 | 32.9% | Coming soon | Coming soon |

### Reasoning

- Winner: Not comparable
- Claude Opus 4.8 public-lane score: 62.9 (#24/28)
- Mistral Medium 3.5 128B public-lane score: 73.7 (Unranked · 2 rankable rows)

| Benchmark | Claude Opus 4.8 | Mistral Medium 3.5 128B | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-2 | 72.1% | Coming soon | Coming soon |
| ARC-AGI-3 | 1.5% | Coming soon | Coming soon |
| ARC-AGI-1 | 92.50% | Coming soon | Coming soon |

### Multimodal & Grounded

- Winner: Not comparable
- Claude Opus 4.8 public-lane score: 91.2 (#5/54)
- Mistral Medium 3.5 128B public-lane score: 60.1 (Unranked · 1 rankable row)

| Benchmark | Claude Opus 4.8 | Mistral Medium 3.5 128B | Winner |
|-----------|-----------|-----------|--------|
| OfficeQA Pro | 66.2% | Coming soon | Coming soon |
| ScreenSpot Pro | 87.9% | Coming soon | Coming soon |
| CharXiv | 89.9% | Coming soon | Coming soon |
| CharXiv w/o tools | 80.5% | Coming soon | Coming soon |

### Knowledge

- Winner: Claude Opus 4.8
- Claude Opus 4.8 public-lane score: 70.7 (Supported · #14/177)
- Mistral Medium 3.5 128B public-lane score: 31.9 (Supported · #139/177)

| Benchmark | Claude Opus 4.8 | Mistral Medium 3.5 128B | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 93.6% | Coming soon | Coming soon |
| GPQA-D | 93.6% | Coming soon | Coming soon |
| HLE | 57.9% | Coming soon | Coming soon |
| HLE w/o tools | 49.8% | Coming soon | Coming soon |
| GPQA Diamond (Vals) | 92.4% | 34.8% | Claude Opus 4.8 |
| MMLU-Pro (Vals) | 89.6% | 75.3% | Claude Opus 4.8 |

### Multilingual

- Winner: Not comparable
- Claude Opus 4.8 public-lane score: Coming soon
- Mistral Medium 3.5 128B public-lane score: Coming soon

| Benchmark | Claude Opus 4.8 | Mistral Medium 3.5 128B | Winner |
|-----------|-----------|-----------|--------|
| INCLUDE | 87.6% | Coming soon | Coming soon |

### Instruction Following

- Winner: Directional only
- Claude Opus 4.8 public-lane score: 75.4 (#61/127)
- Mistral Medium 3.5 128B public-lane score: 84 (#50/127)

### Mathematics

- Winner: Not comparable
- Claude Opus 4.8 public-lane score: 65.7 (#2/7)
- Mistral Medium 3.5 128B public-lane score: Coming soon

| Benchmark | Claude Opus 4.8 | Mistral Medium 3.5 128B | Winner |
|-----------|-----------|-----------|--------|
| USAMO 2026 | 96.7% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 47.241% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 31.250% | Coming soon | Coming soon |

## FAQ

### Which is better overall, Claude Opus 4.8 or Mistral Medium 3.5 128B?

Claude Opus 4.8 has the higher overall point estimate. Conditional score ranges do not establish rank confidence.

### Where is the biggest gap between Claude Opus 4.8 and Mistral Medium 3.5 128B?

The widest category gap is in agentic, where the averages are 61.6 for Claude Opus 4.8 and 19.2 for Mistral Medium 3.5 128B.

### How many benchmarks does Claude Opus 4.8 cover on BenchLM?

Claude Opus 4.8 currently has 40 sourced benchmark scores on BenchLM.

### How many benchmarks does Mistral Medium 3.5 128B cover on BenchLM?

Mistral Medium 3.5 128B currently has 7 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Claude Opus 4.8 vs Claude Opus 5.5](/compare/claude-opus-4-8-vs-claude-opus-5-5)
- [Mistral Medium 3.5 128B vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-mistral-medium-3-5-128b)
- [Claude Opus 4.8 vs GPT-6 Astra](/compare/claude-opus-4-8-vs-gpt-6-astra)
- [Mistral Medium 3.5 128B vs GPT-6 Astra](/compare/gpt-6-astra-vs-mistral-medium-3-5-128b)

## Explore More

- [Claude Opus 4.8 profile](/models/claude-opus-4-8)
- [Mistral Medium 3.5 128B profile](/models/mistral-medium-3-5-128b)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)