Claude Haiku 4.5 vs Kimi K2 (0905)
Anthropic Claude Haiku 4.5 | Moonshot AI Kimi K2 (0905) | |
|---|---|---|
| Overview | ||
| Company | Anthropic | Moonshot AI |
| Release date | Oct 15 2025 | 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. | 77% | — |
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. | 73.3%Best | 65.8% |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 73% | 75.1%Best |
| Timeline | ||
| Release gap | Kimi K2 (0905) shipped 40 days before Claude Haiku 4.5 | |
Which is better: Claude Haiku 4.5 or Kimi K2 (0905)?
Claude Haiku 4.5 and Kimi K2 (0905) are evenly matched across the 2 benchmarks they both report (SWE-Bench Verified, GPQA Diamond). Kimi K2 (0905) shipped 40 days before Claude Haiku 4.5, so benchmark comparisons should account for the intervening progress.
Claude Haiku 4.5 is proprietary, while Kimi K2 (0905) is open weight.
On SWE-Bench Verified, Claude Haiku 4.5 leads at 73.3% vs Kimi K2 (0905) at 65.8%. On GPQA Diamond, Kimi K2 (0905) leads at 75.1% vs Claude Haiku 4.5 at 73%.
Frequently asked questions
Claude Haiku 4.5 was released by Anthropic on Oct 15 2025.
Kimi K2 (0905) was released by Moonshot AI on Sep 5 2025.
Claude Haiku 4.5 leads on SWE-Bench Verified — Claude Haiku 4.5 73.3% vs Kimi K2 (0905) 65.8%.
Kimi K2 (0905) leads on GPQA Diamond — Claude Haiku 4.5 73% vs Kimi K2 (0905) 75.1%.
Claude Haiku 4.5 is a proprietary model released by Anthropic. Kimi K2 (0905) is an open weight model released by Moonshot AI.