Claude Sonnet 4.6 vs Kimi K2 (0905)
Anthropic Claude Sonnet 4.6 | Moonshot AI Kimi K2 (0905) | |
|---|---|---|
| Overview | ||
| Company | Anthropic | Moonshot AI |
| Release date | Feb 17 2026 | Sep 5 2025 |
| Access | Proprietary | Open Weight |
| Specifications | ||
Parameters | — | 1T |
Context window | — | 256k |
| 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. | 91% | — |
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. | 79.6%Best | 65.8% |
Agentic coding CursorBench v3.1Cursor's own test of harder, real-world coding tasks inside a code editor. Higher is better. | 49% | — |
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. | 58% | — |
Multi-step tool use MCP AtlasCan the AI chain together many tools and steps to complete one bigger task, rather than doing just a single thing? Higher is better. | 69.5% | — |
Multidisciplinary reasoning Humanity's Last Exam · no toolsHumanity's Last Exam — extremely hard expert questions across many subjects, written so you can't just look up the answer. “No tools” means the AI answers on its own. Higher is better. | 33.2% | — |
Abstract reasoning ARC-AGI-2Puzzle-style tests of abstract reasoning and pattern-finding — the kind of thing people find easy but AIs often struggle with. Higher is better. | 58.3% | — |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 89.9%Best | 75.1% |
Agentic computer use OSWorld-VerifiedCan the AI actually operate a computer — clicking, typing, and using real apps — to finish tasks on its own? Higher is better. | 72.5% | — |
Agentic financial analysis Finance Agent v2Tests the AI on real financial-analysis work, like digging through reports and making sound decisions. Higher is better. | 51% | — |
Knowledge work GDPval-AAMeasures how well the AI does economically valuable knowledge work, judged against human experts. Shown as a rating (like a chess Elo) — higher is better. | 1676 | — |
Chart reasoning CharXiv ReasoningCan the AI read and reason about complex charts and figures, not just text? Higher is better. | 72.4% | — |
Multimodal reasoning MMMU-ProA tougher version of MMMU — college-level questions that mix images, diagrams, and text together. Higher is better. | 74.5% | — |
Spatial reasoning Blueprint-Bench 2Can the AI reason about space and layout — for example, understanding a floor plan or blueprint? Higher is better. | 6.7% | — |
Long context MRCR v2 (8-needle) · 128k averageTests whether the AI can find specific details buried inside a very long document (around 128k tokens — roughly a long book). Higher is better. | 84.9% | — |
Community preference (code) Arena Elo (Code)Like the text arena, but people vote on which AI writes better code. The votes become a chess-style Elo rating on arena.ai. Higher is better. | 1521 | — |
| Timeline | ||
| Release gap | Kimi K2 (0905) shipped 165 days before Claude Sonnet 4.6 | |
Which is better: Claude Sonnet 4.6 or Kimi K2 (0905)?
Claude Sonnet 4.6 leads Kimi K2 (0905) on 2 of the 2 benchmarks they both report (SWE-Bench Verified, GPQA Diamond). Kimi K2 (0905) shipped 165 days before Claude Sonnet 4.6, so benchmark comparisons should account for the intervening progress.
Claude Sonnet 4.6 is proprietary, while Kimi K2 (0905) is open weight.
On SWE-Bench Verified, Claude Sonnet 4.6 leads at 79.6% vs Kimi K2 (0905) at 65.8%. On GPQA Diamond, Claude Sonnet 4.6 leads at 89.9% vs Kimi K2 (0905) at 75.1%.
Frequently asked questions
Claude Sonnet 4.6 was released by Anthropic on Feb 17 2026.
Kimi K2 (0905) was released by Moonshot AI on Sep 5 2025.
Claude Sonnet 4.6 leads on SWE-Bench Verified — Claude Sonnet 4.6 79.6% vs Kimi K2 (0905) 65.8%.
Claude Sonnet 4.6 leads on GPQA Diamond — Claude Sonnet 4.6 89.9% vs Kimi K2 (0905) 75.1%.
Claude Sonnet 4.6 is a proprietary model released by Anthropic. Kimi K2 (0905) is an open weight model released by Moonshot AI.
Other comparisons
Claude Sonnet 4.6 vs GPT-5.6 SolKimi K2 (0905) vs GPT-5.6 SolClaude Sonnet 4.6 vs Gemini OmniKimi K2 (0905) vs Gemini OmniClaude Sonnet 4.6 vs Muse Spark 1.1Kimi K2 (0905) vs Muse Spark 1.1Claude Sonnet 4.6 vs Grok 4.5Kimi K2 (0905) vs Grok 4.5Claude Sonnet 4.6 vs DeepSeek-V4-ProKimi K2 (0905) vs DeepSeek-V4-ProClaude Sonnet 4.6 vs Mistral Medium 3.5Kimi K2 (0905) vs Mistral Medium 3.5