# Kimi K2 (0905)

Kimi K2 (0905) is an AI model released by Moonshot AI on Sep 5 2025. It has 1T parameters, a 256k context window and open weight. Tracked results include 65.8% on SWE-Bench Verified and 75.1% on GPQA Diamond.

## Facts

| Field | Value |
| --- | --- |
| Model | Kimi K2 (0905) |
| Developer | Moonshot AI |
| Release date | Friday, Sep 5 2025 |
| Licensing | Open Weight |
| Parameters | 1T |
| Context window | 256k |

## Tracked benchmark scores

| Benchmark | Score | Source | What it measures |
| --- | --- | --- | --- |
| SWE-Bench Verified | 65.8% | Lab | Real 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. |
| GPQA Diamond | 75.1% | Lab | Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. |

## About Kimi K2 (0905)

Kimi K2 (0905) was Moonshot AI's September 2025 update to the K2 instruction model. It retained the trillion-parameter mixture-of-experts design with approximately 32 billion active parameters per token, while expanding context from 128,000 to 256,000 tokens. The model card emphasized stronger agentic coding and improvements in both the appearance and practicality of generated frontend code.

The dated checkpoint matters because it was evaluated separately from the original July release. Moonshot reported 69.2% on SWE-bench Verified across five runs under its documented harness, compared with 65.8% for the earlier version. The release offered a more capable instruction checkpoint within the existing K2 generation, before the separately named Thinking model introduced a different reasoning profile.

## Questions and answers

### When was Kimi K2 (0905) released?

Kimi K2 (0905) was released by Moonshot AI on Friday, Sep 5 2025.

### Who made Kimi K2 (0905)?

Kimi K2 (0905) was built by Moonshot AI. Chinese AI company building the Kimi family of models. Founded in 2023, known for long-context and efficient MoE architectures.

### What benchmark scores did Kimi K2 (0905) get?

Kimi K2 (0905) reports 2 tracked benchmark scores — SWE-Bench Verified: 65.8%; GPQA Diamond: 75.1%. Tracked scores may come from lab reports or independent benchmarks; source details accompany the benchmark data.

### What is the context window of Kimi K2 (0905)?

Kimi K2 (0905) has a context window of 256k. Providers may specify separate input and output token limits.

### How many parameters does Kimi K2 (0905) have?

Kimi K2 (0905) is reported at 1T parameters.

### Is Kimi K2 (0905) open source?

Partly. Kimi K2 (0905) is an open-weight model: the trained weights are free to download and run locally or on your own infrastructure, but the training data and code are not fully released and the license may restrict some commercial uses. It is not open source in the strict sense.

### What came before and after Kimi K2 (0905)?

Moonshot AI's previous tracked release was Kimi K2 on Jul 11 2025, 56 days earlier. It was followed by Kimi Linear on Oct 30 2025.


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Canonical page: https://aireleasetracker.com/model/moonshot/kimi-k2-(0905)
Site index: https://aireleasetracker.com/llms.txt
Source: AI Release Tracker (https://aireleasetracker.com). Most benchmark scores come from lab launch material; gathered results identify the leaderboard that published them.