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LFM2.5-8B-A1B-Base

LFM2.5 is a new family of hybrid models designed for on-device deployment. It builds on the LFM2 architecture with extended pre-training and reinforcement learning.

  • On-device personal assistant: Designed to power real-life applications, chaining tool calls, and following complex instructions on all devices.
  • Compressed performance: Competitive with much larger dense and MoE models on instruction following and agentic tasks.
  • Unmatched throughput: Fastest in its size class on both CPU and GPU inference, with day-one support for llama.cpp, MLX, vLLM, and SGLang.

Find more information about LFM2.5-8B-A1B in our blog post.

image

*AA-Omniscience Index (higher is better) rewards correct answers and penalizes hallucinations. Scores range from -100 to 100. See more results on Artificial Analysis.

🗒️ Model Details

Model Parameters Description
LFM2.5-8B-A1B-Base 8.3B total / 1.5B active Pre-trained base model for fine-tuning
LFM2.5-8B-A1B 8.3B total / 1.5B active Reasoning-tuned general-purpose model

LFM2.5-8B-A1B is a general-purpose text-only model with the following features:

  • Total parameters: 8.3B
  • Active parameters: 1.5B
  • Number of layers: 24 (18 double-gated LIV conv + 6 GQA)
  • Training budget: 38 trillion tokens
  • Context length: 131,072
  • Vocabulary size: 128,000
  • Languages: English, Arabic, Chinese, French, German, Japanese, Korean, Portuguese, Spanish
  • Generation parameters: We recommend the following parameters:
    • temperature: 0.2
    • top_p: 80
    • repetition_penalty: 1.05
Model Description
LFM2.5-8B-A1B Original model checkpoint in native format. Best for fine-tuning or inference with Transformers, vLLM, and SGLang.
LFM2.5-8B-A1B-GGUF Quantized format for llama.cpp and compatible tools. Optimized for edge inference and local deployment.
LFM2.5-8B-A1B-ONNX ONNX Runtime format for cross-platform deployment.
LFM2.5-8B-A1B-MLX MLX format for Apple Silicon. Optimized for fast inference on Mac devices.

We recommend using LFM2.5-8B-A1B for agentic workflows, tool use, structured outputs, multilingual assistants, and on-device personal-assistant applications. It is not the best fit for heavy programming or knowledge-intensive question answering without retrieval.

🏃 Inference

LFM2.5-8B-A1B is supported by many inference frameworks. See the Inference documentation for the full list.

Name Description Docs Notebook
Transformers Simple inference with direct access to model internals. Link Colab link
vLLM High-throughput production deployments with GPU. Link Colab link
llama.cpp Cross-platform inference with CPU offloading. Link Colab link
MLX Apple's machine learning framework optimized for Apple Silicon. Link
LM Studio Desktop application for running LLMs locally. Link

Quick start with Transformers (compatible with transformers>=5.0.0):

from transformers import AutoModelForCausalLM, AutoTokenizer, TextStreamer

model_id = "LiquidAI/LFM2.5-8B-A1B-Base"
model = AutoModelForCausalLM.from_pretrained(
    model_id,
    device_map="auto",
    dtype="bfloat16",
#   attn_implementation="flash_attention_2" <- uncomment on compatible GPU
)
tokenizer = AutoTokenizer.from_pretrained(model_id)
streamer = TextStreamer(tokenizer, skip_prompt=True, skip_special_tokens=True)

prompt = "What is C. elegans?"

input_ids = tokenizer.apply_chat_template(
    [{"role": "user", "content": prompt}],
    add_generation_prompt=True,
    return_tensors="pt",
    tokenize=True,
).to(model.device)

output = model.generate(
    input_ids,
    do_sample=True,
    temperature=0.2,
    top_k=80,
    repetition_penalty=1.05,
    max_new_tokens=8192,
    streamer=streamer,
)

🔧 Fine-Tuning

We recommend fine-tuning LFM2.5 for your specific use case to achieve the best results.

Name Description Docs Notebook
CPT (Unsloth) Continued Pre-Training using Unsloth for text completion. Link Colab link
CPT (Unsloth) Continued Pre-Training using Unsloth for translation. Link Colab link
SFT (Unsloth) Supervised Fine-Tuning with LoRA using Unsloth. Link Colab link
SFT (TRL) Supervised Fine-Tuning with LoRA using TRL. Link Colab link
DPO (TRL) Direct Preference Optimization with LoRA using TRL. Link Colab link
GRPO (Unsloth) GRPO with LoRA using Unsloth. Link Colab link
GRPO (TRL) GRPO with LoRA using TRL. Link Colab link

📬 Contact

Citation

@article{liquidAI20268BA1B,
  author  = {Liquid AI},
  title   = {LFM2.5-8B-A1B: Personal Assistant On Your Laptop},
  journal = {Liquid AI Blog},
  year    = {2026},
  note    = {www.liquid.ai/blog/lfm2-5-8b-a1b},
}
@article{liquidai2025lfm2,
  title   = {LFM2 Technical Report},
  author  = {Liquid AI},
  journal = {arXiv preprint arXiv:2511.23404},
  year    = {2025}
}
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