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Claude Opus 4.5 vs Mistral Medium 3.5

2 vs 0 benchmarks won

Anthropic
Claude Opus 4.5
Mistral
Mistral Medium 3.5
Overview
CompanyAnthropicMistral
Release dateNov 24 2025Apr 29 2026
Model type
Open sourceNoYes
Specifications
Parameters
128B
Context window
256k
Benchmarks
Science reasoning
GPQA Diamond
87%
Software engineering
SWE-Bench Verified
80.9%
77.6%
Multimodal understanding
MMMU
Timeline
Release gapClaude Opus 4.5 shipped 156 days before Mistral Medium 3.5

Which is better: Claude Opus 4.5 or Mistral Medium 3.5?

Claude Opus 4.5 leads Mistral Medium 3.5 on 2 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). Claude Opus 4.5 shipped 156 days before Mistral Medium 3.5, so benchmark comparisons should account for the intervening progress.

Mistral Medium 3.5 is an open-source / open-weight model; Claude Opus 4.5 is proprietary.

On SWE-Bench Verified, Claude Opus 4.5 scores 80.9%, 3.3 points above Mistral Medium 3.5 at 77.6%.

Frequently asked questions

When was Claude Opus 4.5 released?
Claude Opus 4.5 was released by Anthropic on Nov 24 2025.
When was Mistral Medium 3.5 released?
Mistral Medium 3.5 was released by Mistral on Apr 29 2026.
Which is better at coding, Claude Opus 4.5 or Mistral Medium 3.5?
On SWE-Bench Verified (real-world software-engineering tasks), Claude Opus 4.5 leads — Claude Opus 4.5 scores 80.9% and Mistral Medium 3.5 scores 77.6%.
Is Claude Opus 4.5 or Mistral Medium 3.5 open source?
Mistral Medium 3.5 is an open-source / open-weight model released by Mistral. Claude Opus 4.5 is a proprietary model released by Anthropic.

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