Moonshot AI · 2026-10-23 · seismic
Kimi K3.1 Pro — Moonshot's 3T-class model for coding, 3D and finance
Kimi K3.1 Pro is a post-trained upgrade of Kimi K3 with a 1M-token context. It scores 65.7% on Terminal-Bench 4.0 and cuts K3's hard hallucination rate from 23.4% to 8.3%. Open weights are promised by November 4.
Moonshot's post-trained Kimi K3 upgrade targets long coding jobs, 3D modelling and finance work, with open weights due by November 4.
Key specs
| Terminal bench 4.0 | 65.7% |
|---|---|
| Aa intelligence index | 55 |
Quick facts
| Maker | Moonshot AI |
|---|---|
| Size | 3T-class (post-trained Kimi K3) |
| Context window | 1M tokens |
| API model IDs | kimi-k3.1-pro, kimi-k3.1-pro-highspeed |
| Open weights | Promised by November 4, 2026 |
| Highspeed variant | 2-3x faster, same capabilities |
Benchmarks
| Claude Opus 5.5 | 96.2 IoU | |
|---|---|---|
| GPT-6 Astra | 95.9 IoU | |
| Kimi K3.1 Pro | 92.7 IoU | |
| Claude Fable 5.1 | 92.6 IoU | |
| DeepSeek-V4.1-Flash-1017 | 81.6 IoU |
What is it?
Kimi K3.1 Pro is the first model in Moonshot AI's K3.1 series, a 3T-class model that Moonshot calls its most capable open-weight model so far. A Highspeed variant runs 2-3x faster with the same capabilities. Both are live in the Kimi apps, Kimi Work, Kimi Code and the Kimi API today.
How does it work?
Moonshot built K3.1 Pro by giving Kimi K3 much more post-training compute, running joint reinforcement learning across hundreds of domains with better rollout scheduling, sandboxes and environment checks. The model can write and run scripts for Blender and CAD tools, and drive Unity, Unreal Engine and Godot together with web search. Before the open-weight release, Moonshot removed cyber-related data from mid-training and RL.
Why does it matter?
On Moonshot's own tables the new Kimi sits next to Claude Opus 5.5 on Terminal-Bench 4.0 (65.7% vs 66.4%) and ahead of GPT-6 Astra (58.2%). Artificial Analysis gives it a score of 55 on its Intelligence Index. If the weights land as promised, open-model users get a frontier-level option for long agent tasks.
Who is it for?
developers using agents for long coding tasks, 3D and finance teams
Frequently asked questions
- When will Kimi K3.1 Pro open weights be released?
- Moonshot AI says the full Kimi K3.1 Pro weights will be published by November 4, 2026. At launch on October 23 the model is available only through Kimi.ai, the Kimi mobile apps, Kimi Work, Kimi Code and the Kimi API. The launch post does not yet link a Hugging Face repository or name the license.
- How much does Kimi K3.1 Pro cost on the API?
- Artificial Analysis lists Kimi K3.1 Pro on the Kimi API at $2.00 per million input tokens and $10.00 per million output tokens, with a 1M-token context and about 73.5 output tokens per second. Moonshot's launch post itself does not list prices, so check the Kimi API platform before you budget.
- How does Kimi K3.1 Pro compare to Claude Opus 5.5 and GPT-6 Astra?
- On Terminal-Bench 4.0 Moonshot reports Kimi K3.1 Pro at 65.7%, Claude Opus 5.5 at 66.4% and GPT-6 Astra at 58.2%. On BenchCAD 3D modelling with tools, Kimi K3.1 Pro scores 92.7 against 96.2 for Opus 5.5 and 95.9 for GPT-6 Astra. These are Moonshot's own numbers.
- Is Kimi K3.1 Pro less capable at cybersecurity on purpose?
- Yes. Moonshot removed cyber-related data from the mid-training and RL stages of Kimi K3.1 Pro before the open-weight release. On xdev-bench-hard (pass@3) it scores 81.0, while Moonshot's own model without that risk reduction scores 90.5. Moonshot says it remains behind frontier closed models that have been public for at least three months.
- How do I use Kimi K3.1 Pro in Kimi Code?
- In Kimi Code, pick Kimi K3.1 Pro with the /model command. Kimi Work needs desktop version 3.1.0 or later on Windows or Apple silicon Macs. Kimi Business admins must turn the model on, because it is off by default for enterprise accounts at launch.
Try it
Kimi API model id: kimi-k3.1-pro (or kimi-k3.1-pro-highspeed)