Model reference · open weights

KAT

LLMs Kwaipilot Text gen 1 build Its own licence terms 177 dl/mo

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.

  • KAT is an open-source text-generation model developed by Kwaipilot that uses a two-stage training pipeline to decide when to produce explicit chain-of-thought reasoning.
  • The model features 40.6 billion parameters, supports a context length of 131,072 tokens, and is multilingual.
  • It is released under an other licence and includes a structured template for machine-parsable responses.

Summary of the Kwaipilot/KAT-V1-40B model card, 2026-10-01

What it is

Released byKwaipilot
Released2025-07-20
Parameters40.6B
VRAM81.1 GB for the weights

What it runs on

Memory and cards for KAT-V1-40B (BF16)

81.1 GBweights, file size
328 MBcache per 1K tokens
896 MBruntime overhead, at least
131,072 tokenscontext max
CardRequests at onceContext maxMemory
8K each32K each
RTX 3060 12 GB … H100 80 GB
8 smaller cards
———
RTX PRO 6000 Blackwell 96 GB2—20K93.8 GB
DGX Spark (GB10) 128 GB unified7161K107 GB
H200 141 GB194all 128K138 GB
B200 180 GB328all 128K176 GB
4× RTX 4090 24 GB
tensor parallel
3—25K23.4 GB a card
4× RTX 3090 24 GB
tensor parallel
3—26K23.4 GB a card
4× RTX 5090 32 GB
tensor parallel
143117K31.0 GB a card
2× H100 80 GB
tensor parallel
235all 128K78.1 GB a card
2× A100 80 GB
tensor parallel
276all 128K78.2 GB a card
4× L40S 48 GB
tensor parallel
338all 128K44.0 GB a card
2× RTX PRO 6000 Blackwell 96 GB
tensor parallel
358all 128K93.8 GB a card
Memory needed at each load
Requests at once8K tokens each32K tokens each
184.7 GB92.8 GB
595.4 GB136 GB
8104 GB168 GB
16125 GB254 GB
32168 GB426 GB
64254 GB769 GB

One card, with vLLM's small-card settings.

From the model card

What Kwaipilot says about KAT

Read the model card
  • We released the technical report of the KAT-V1 model, available at https://arxiv.org/pdf/2507.08297.
  • Kwaipilot-AutoThink ranks first among all open-source models on LiveCodeBench Pro, a challenging benchmark explicitly designed to prevent data leakage, and even surpasses strong proprietary systems such as Seed and o3-mini.

Introduction

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.

Data Format

KAT produces responses in a structured template that makes the reasoning path explicit and machine-parsable. Two modes are supported:

Special Tokens

TokenDescription
``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.

🔧 Quick Start

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. 🌐🤖
"""

Future Releases

Looking ahead, we will publish a companion paper that fully documents the AutoThink training framework, covering:

  • Cold-start initialization procedures
  • Reinforcement-learning (Step-SRPO) strategies
  • Data curation and reward design details

At the same time, we will open-source:

  • Training resources – the curated dual-regime datasets and RL codebase
  • Model suite – checkpoints at 1.5B, 7B, and 13B parameters, all trained with AutoThink gating

Citation

@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.

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