What is the Kimi K2.8 Preview? When was it...

------ Chat Conversation ------

User: What is the Kimi K2.8 Preview? When was it announced? How does it benchmark?

Assistant: Kimi K2.8 Preview is Moonshot AI’s proprietary coding and agentic model, offering multimodal input, adjustable thinking effort (low, high, or max), and a context window of up to 1 million tokens. In Kimi Code it retains the kimi-for-coding model ID, so existing clients require no configuration change kimi.com llm-stats.com.

It was announced and fully rolled out in Kimi Code on September 11, 2026 kimi.com.

Benchmark picture: Moonshot says its coding and agent capabilities improved across the board, perform close to Kimi K3, and use significantly more efficient thinking than K2.7 Code kimi.com. However, no numerical K2.8 benchmark scores or independent K2.8 evaluation were available in the reviewed evidence as of September 17, 2026; Artificial Analysis lists its benchmark methodology and Kimi models generally, but does not report K2.8-specific results on the cited page artificialanalysis.ai.

Working notes:
- Identify Kimi K2.8 Preview, determine its announcement date, and summarize reported benchmark performance using official and independent sources current to September 17, 2026.
- The existing results identify the official changelog but do not expose K2.8's benchmark figures; locate the exact official release entry.
- Verify the official K2.8 Preview announcement, positioning, rollout details, and benchmark claims.
- Corroborate the release date and reported capabilities from an independent news page.
- Check the detailed article surfaced by search for rollout and benchmark context.

Sources:
- llm-stats.com: https://llm-stats.com/models/kimi-k2.8 (fetched/scraped page)
- AI Model & API Providers Analysis | Artificial Analysis: https://artificialanalysis.ai/ (fetched/scraped page)
- moonshotai/Kimi-K2.6 · Hugging Face: https://huggingface.co/moonshotai/Kimi-K2.6 (fetched/scraped page)
- Moonshot AI Launches Kimi K2.8 Preview Multimodal Model: https://emergent.sh/news/moonshot-ai-launches-kimi-k2-8-preview (fetched/scraped page)
- What's New | Kimi Code Docs: https://www.kimi.com/code/docs/en/kimi-code/whats-new.html (fetched/scraped page)
- Moonshot AI: https://www.moonshot.ai/ (fetched/scraped page)
- Kimi K2.6 Tech Blog: Advancing Open-Source Coding: https://www.kimi.ai/blog/kimi-k2-6 (fetched/scraped page)
- platform.kimi.ai: https://platform.kimi.ai/docs/models (fetched/scraped page)
- Kimi K3 achieves #3 in the Artificial Analysis Intelligence Index, comparable to Opus 4.8 and GPT-5.5: https://artificialanalysis.ai/articles/kimi-k3-achieves-3-in-the-artificial-analysis-intelligence-index-comparable-to-opus-4-8-and-gpt-5-5 (fetched/scraped page)
- Moonshot Rolls Out Kimi K2.8 Preview Across Kimi Code ...: https://x.com/i/article/2099456099057308070 (search result only)
- Moonshot AI Launches Kimi K2.8 Preview Multimodal Model: https://emergent.sh/news/moonshot-ai-launches-kimi-k2-8-preview-c545d (search result only)
- Kimi K3 is underscoring in benchmarks : r/kimi: https://www.reddit.com/r/kimi/comments/1v1ew2s/kimi_k3_is_underscoring_in_benchmarks/ (search result only)
- r/singularity - Independent third party benchmarks are now ...: https://www.reddit.com/r/singularity/comments/1qr82bk/independent_third_party_benchmarks_are_now/ (search result only)
- CoreWeave Leads Artificial Analysis Kimi K2.6 Benchmark: https://www.coreweave.com/blog/coreweave-is-now-the-fastest-at-inference-on-the-best-open-source-model-kimi-k2-6 (search result only)
- Kimi K3 achieves #3 in the Artificial Analysis Intelligence ...: https://www.linkedin.com/pulse/kimi-k3-launches-57-artificial-analysis-intelligence-clwlc (search result only)
- moonshotai/Kimi-K2-Instruct: https://huggingface.co/moonshotai/Kimi-K2-Instruct (search result only)
- moonshotai/Kimi-K2.7-Code: https://huggingface.co/moonshotai/Kimi-K2.7-Code (search result only)
- Kimi K2.6 Released (huggingface) : r/LocalLLaMA: https://www.reddit.com/r/LocalLLaMA/comments/1sqscao/kimi_k26_released_huggingface/ (search result only)


------ Research Draft Summary ------

# Kimi K2.8 Preview

Kimi K2.8 Preview is Moonshot AI’s proprietary multimodal model for coding and agentic work, fully rolled out in Kimi Code on September 11, 2026; Moonshot characterizes its performance as close to Kimi K3, but the available evidence contains no numerical or independent K2.8 benchmark results.

## Model and availability

K2.8 Preview sits between K2.7 Code and the K3 flagship in Moonshot’s lineup. Its principal features are:

- Multimodal input.
- A context window of up to 1 million tokens.
- Adjustable thinking effort at `low`, `high`, or `max`, with `max` as the default.
- Improved coding and agent capabilities over K2.7 Code.
- Significantly more efficient thinking than K2.7 Code.
- The unchanged `kimi-for-coding` model ID, allowing existing Kimi Code clients and third-party tools to continue without configuration changes.

These details come from the official Kimi Code release notes and a third-party model listing [kimi.com](https://www.kimi.com/code/docs/en/kimi-code/whats-new.html) [llm-stats.com](https://llm-stats.com/models/kimi-k2.8).

## Announcement date

Moonshot fully rolled out K2.8 Preview in Kimi Code on **September 11, 2026** [kimi.com](https://www.kimi.com/code/docs/en/kimi-code/whats-new.html). A later report identifies the same date as its official release [emergent.sh](https://emergent.sh/news/moonshot-ai-launches-kimi-k2-8-preview).

## Benchmark evidence

The available performance claim is qualitative rather than numerical. Moonshot says K2.8 Preview delivers coding and agent performance close to K3 while thinking more efficiently than K2.7 Code [kimi.com](https://www.kimi.com/code/docs/en/kimi-code/whats-new.html).

No K2.8-specific scores, benchmark tables, test settings, latency measurements, or independent evaluations appear in the available sources. K3 results therefore cannot establish K2.8’s performance, even though Moonshot describes the two models as close.

## What would sharpen this

- Moonshot’s K2.8 benchmark report would quantify the claimed gains over K2.7 Code and proximity to K3.
- Independent evaluations under identical thinking settings would test the provider’s qualitative claims.
- Pricing, latency, and token-use measurements would establish whether “more efficient thinking” produces lower cost or faster completion.

## Related questions

- How does K2.8 Preview compare with K3 on coding, agentic, and long-context evaluations?
- How do its `low`, `high`, and `max` thinking settings affect accuracy, latency, and cost?
- Is K2.8 Preview available through the general Kimi API or only through Kimi Code?
- What image formats and multimodal tasks does K2.8 Preview support?