Claude Sonnet 4.5 vs Devstral Small
Anthropic Claude Sonnet 4.5 | Mistral Devstral Small | |
|---|---|---|
| Overview | ||
| Company | Anthropic | Mistral |
| Release date | Sep 29 2025 | May 21 2025 |
| Access | Proprietary | Open Weight |
| Specifications | ||
Parameters | — | 24B |
| Benchmarks | ||
Nonsense detection BullshitBench v2Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 79% | — |
Coding SWE-Bench VerifiedReal coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | 77.2% | — |
Next.js coding Next.js EvalsVercel's open eval of how well AI coding agents build and migrate real Next.js apps — measured as the share of tasks the agent completes successfully. Higher is better. | 50% | — |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 83.4% | — |
Multimodal MMMUTests the AI on understanding images and text together across many college subjects. Higher is better. | 68% | — |
| Timeline | ||
| Release gap | Devstral Small shipped 131 days before Claude Sonnet 4.5 | |
Which is better: Claude Sonnet 4.5 or Devstral Small?
Claude Sonnet 4.5 and Devstral Small don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Devstral Small shipped 131 days before Claude Sonnet 4.5, so benchmark comparisons should account for the intervening progress.
Claude Sonnet 4.5 is proprietary, while Devstral Small is open weight.
Direct benchmark comparisons are unavailable — Claude Sonnet 4.5 and Devstral Small don't publish scores on any of the same benchmarks.
Frequently asked questions
Claude Sonnet 4.5 was released by Anthropic on Sep 29 2025.
Devstral Small was released by Mistral on May 21 2025.
Claude Sonnet 4.5 is a proprietary model released by Anthropic. Devstral Small is an open weight model released by Mistral.
Other comparisons
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