Kimi K2.6vsComposer 2
Kimi K2.6 | Composer 2 | |
|---|---|---|
| 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. | 65% | — |
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. | 80.2% | — |
Multilingual coding SWE-Bench MultilingualLike SWE-Bench, but the coding problems span many programming languages, not just one. Tests how broadly the AI can code. Higher is better. | — | 73.7% |
Agentic coding CursorBench v3.1Cursor's own test of harder, real-world coding tasks inside a code editor. Higher is better. | 47.6% | 52.2%Best |
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. | 67% | 75%Best |
Competitive coding LiveCodeBenchCoding problems published so recently the AI can't have seen them in training — a contamination-free test of raw programming skill. Higher is better. | 89.6% | — |
Agentic terminal coding Terminal-Bench 2.0Can the AI work in a command-line terminal — running commands and finishing technical setup tasks the way a developer would? (Version 2.0 of the test.) Higher is better. | — | 61.7% |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 90.5% | — |
Community preference Arena Elo (Text)Real people chat with two anonymous AIs side by side and vote for the answer they prefer. Votes become a chess-style Elo rating on arena.ai — it measures which AI people actually like, not test scores. Higher is better. | 1461 | — |
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. | 1513 | — |
| Overview | ||
| Company | Moonshot AI | SpaceXAI |
| Release date | Apr 21 2026 | Mar 19 2026 |
| Access | Open Weight | Proprietary |
Which is better: Kimi K2.6 or Composer 2?
Composer 2 leads Kimi K2.6 on 2 of the 2 benchmarks they both report (CursorBench v3.1, Next.js Evals). Composer 2 shipped 33 days before Kimi K2.6, so benchmark comparisons should account for the intervening progress.
Kimi K2.6 is open weight, while Composer 2 is proprietary.
On CursorBench v3.1, Composer 2 leads at 52.2% vs Kimi K2.6 at 47.6%. On Next.js Evals, Composer 2 leads at 75% vs Kimi K2.6 at 67%.
Frequently asked questions
Kimi K2.6 was released by Moonshot AI on Apr 21 2026.
Composer 2 was released by SpaceXAI on Mar 19 2026.
Composer 2 leads on CursorBench v3.1 — Kimi K2.6 47.6% vs Composer 2 52.2%.
Kimi K2.6 is an open weight model released by Moonshot AI. Composer 2 is a proprietary model released by SpaceXAI.
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