Model reference · open weights
KAT is an open-weight language model from Kwaipilot. KAT-V1-40B (BF16) weighs 81.1 GB; the smallest configuration that runs it is 4× RTX 4090 24 GB.
Summary of the Kwaipilot/KAT-V1-40B model card, 2026-10-01
What it is
| Released by | Kwaipilot |
|---|---|
| Released | 2025-07-20 |
| Parameters | 40.6B |
| VRAM | 81.1 GB for the weights |
What it runs on
| Card | Requests at once | Context max | Memory | |
|---|---|---|---|---|
| 8K each | 32K each | |||
| RTX 3060 12 GB … H100 80 GB 8 smaller cards | — | — | — | |
| RTX PRO 6000 Blackwell 96 GB | 2 | — | 20K | 93.8 GB |
| DGX Spark (GB10) 128 GB unified | 7 | 1 | 61K | 107 GB |
| H200 141 GB | 19 | 4 | all 128K | 138 GB |
| B200 180 GB | 32 | 8 | all 128K | 176 GB |
| 4× RTX 4090 24 GB tensor parallel | 3 | — | 25K | 23.4 GB a card |
| 4× RTX 3090 24 GB tensor parallel | 3 | — | 26K | 23.4 GB a card |
| 4× RTX 5090 32 GB tensor parallel | 14 | 3 | 117K | 31.0 GB a card |
| 2× H100 80 GB tensor parallel | 23 | 5 | all 128K | 78.1 GB a card |
| 2× A100 80 GB tensor parallel | 27 | 6 | all 128K | 78.2 GB a card |
| 4× L40S 48 GB tensor parallel | 33 | 8 | all 128K | 44.0 GB a card |
| 2× RTX PRO 6000 Blackwell 96 GB tensor parallel | 35 | 8 | all 128K | 93.8 GB a card |
| Requests at once | 8K tokens each | 32K tokens each |
|---|---|---|
| 1 | 84.7 GB | 92.8 GB |
| 5 | 95.4 GB | 136 GB |
| 8 | 104 GB | 168 GB |
| 16 | 125 GB | 254 GB |
| 32 | 168 GB | 426 GB |
| 64 | 254 GB | 769 GB |
One card, with vLLM's small-card settings.
From the model card
KAT (Kwaipilot-AutoThink) is an open-source large-language model that mitigates over-thinking by learning when to produce explicit chain-of-thought and when to answer directly.
Its development follows a concise two-stage training pipeline:
• Think-off queries labeled via a custom tagging system.
• Think-on queries generated by a multi-agent solver.
KAT produces responses in a structured template that makes the reasoning path explicit and machine-parsable. Two modes are supported:
| Token | Description |
|---|---|
| `` | Analyzes the input to decide whether explicit reasoning is needed. |
/ | Indicates whether reasoning is activated (“on”) or skipped (“off”). |
| `` | Marks the start of the chain-of-thought segment when think_on is chosen. |
| `` | Marks the start of the final user-facing answer. |
from transformers import AutoTokenizer, AutoModelForCausalLM
model_name = "Kwaipilot/KAT-V1-40B"
# load the tokenizer and the model
tokenizer = AutoTokenizer.from_pretrained(model_name, trust_remote_code=True)
model = AutoModelForCausalLM.from_pretrained(
model_name,
torch_dtype="auto",
device_map="auto"
)
# prepare the model input
prompt = "Give me a short introduction to large language model."
messages = [
{"role": "user", "content": prompt}
]
text = tokenizer.apply_chat_template(
messages,
tokenize=False,
add_generation_prompt=True
)
model_inputs = tokenizer([text], return_tensors="pt").to(model.device)
# conduct text completion
generated_ids = model.generate(
**model_inputs,
max_new_tokens=65536,
temperature=0.6,
top_p=0.95,
)
output_ids = generated_ids[0][len(model_inputs.input_ids[0]):].tolist()
content = tokenizer.decode(output_ids, skip_special_tokens=True).strip("\n")
print("prompt:\n", prompt)
print("content:\n", content)
"""
prompt:
Give me a short introduction to large language model.
content:
The user's request is to provide a concise factual introduction to large language models, which involves retrieving and summarizing basic information. This task is straightforward as it only requires recalling and presenting well-known details without deeper analysis. No complex reasoning is needed here—just a simple explanation will suffice.
A **Large Language Model (LLM)** is an advanced AI system trained on vast amounts of text data to understand, generate, and process human-like language. Here’s a concise introduction:
### Key Points:
1. **Training**: Trained on diverse text sources (books, websites, etc.) using deep learning.
2. **Capabilities**:
- Answer questions, generate text, summarize content, translate languages.
- Understand context, sentiment, and nuances in language.
3. **Architecture**: Often based on **transformer models** (e.g., BERT, GPT, LLaMA).
4. **Scale**: Billions of parameters, requiring massive computational resources.
5. **Applications**: Chatbots, content creation, coding assistance, research, and more.
### Examples:
- **OpenAI’s GPT-4**: Powers ChatGPT.
- **Google’s Gemini**: Used in Bard.
- **Meta’s LLaMA**: Open-source alternative.
### Challenges:
- **Bias**: Can reflect biases in training data.
- **Accuracy**: May hallucinate "facts" not grounded in reality.
- **Ethics**: Raises concerns about misinformation and job displacement.
LLMs represent a leap forward in natural language processing, enabling machines to interact with humans in increasingly sophisticated ways. 🌐🤖
"""
Looking ahead, we will publish a companion paper that fully documents the AutoThink training framework, covering:
At the same time, we will open-source:
@techreport{Zhan2025KATV1,
title={KAT-V1: Kwai-AutoThink Technical Report},
author={Zizheng, Zhan and Ken, Deng and Huaixi, Tang and Wen, Xiang and Kun, Wu and others},
year={2025},
institution={arXiv preprint arXiv:2507.08297},
number={arXiv:2507.08297},
url={https://arxiv.org/abs/2507.08297}
}
Quoted from the model card on Hugging Face. The full card is behind the Hugging Face link above.