LFM2.5-2.6B

LFM2.5-2.6B

LFM2.5-2.6B is part of LFM2.5, a family of hybrid models designed for on-device deployment. It builds on the LFM2 architecture with a 128K context window and agentic post-training.

• Best-in-class agent: Competitive with models 4x larger on tool use, instruction following, and multi-step agentic tasks.
• Agentic reinforcement learning: Trained inside the most popular agentic harnesses to improve compatibility.
• Efficient inference: 220 tok/s on an Apple M5 Max and 113 tok/s on an AMD Ryzen CPU, in under 2.5 GB of memory.

Find more information about LFM2.5-2.6B in our blog post.

[!NOTE] 💻 Demos: Try LFM2.5-2.6B's agentic capabilities in a Hugging Face space without any setup: Research Agent in your browser: helps you research a specific question and generates a summary

🗒️ Model Details

Model	Parameters	Description
LFM2.5-2.6B-Base	2.6B	Pre-trained base model for fine-tuning
LFM2.5-2.6B	2.6B	Post-trained for agentic workloads

LFM2.5-2.6B is a general-purpose text-only model with the following features:

• Total parameters: 2.69B
• Number of layers: 30 (22 double-gated short convolution blocks + 8 GQA)
• Training budget: 34 trillion tokens
• Vocabulary size: 128,000
• Context length: 131,072 tokens
• Languages: English, Arabic, Chinese, French, German, Italian, Japanese, Korean, Portuguese, Spanish, Vietnamese, Thai, Indonesian, Hindi, Russian, Polish
• Generation parameters:
  • temperature: 0.1
  • top_k: 50
  • repetition_penalty: 1.1

Model	Description
LFM2.5-2.6B	Original model checkpoint in native format. Best for fine-tuning or inference with Transformers, vLLM, and SGLang.
LFM2.5-2.6B-GGUF	Quantized format for llama.cpp and compatible tools. Optimized for CPU inference and local deployment with reduced memory usage.
LFM2.5-2.6B-ONNX	ONNX Runtime format for cross-platform deployment. Enables hardware-accelerated inference across diverse environments (cloud, edge, mobile).
LFM2.5-2.6B-MLX	MLX format for Apple Silicon. Optimized for fast inference on Mac devices using the MLX framework.
LFM2.5-2.6B-DSpark	Speculative decoding drafter (328M). Pair it with this model for ~2.6x faster decoding with identical outputs.

We recommend using it for agentic workloads, tool use, data extraction, RAG, and long-context workflows. It is not recommended for agentic coding and knowledge-heavy tasks.

Chat Template

LFM2.5 uses a ChatML-like format. See the Chat Template documentation for details. Example:

<|startoftext|><|im_start|>system
You are a helpful assistant trained by Liquid AI.<|im_end|>
<|im_start|>user
What is C. elegans?<|im_end|>
<|im_start|>assistant

You can use tokenizer.apply_chat_template() to format your messages automatically.

[!TIP] 💡 Note: LFM2.5-2.6B is a pure reasoning model that always thinks before it answers. It adds a <think> tag directly in the chat template when starting an assistant answer.

Tool Use

LFM2.5 supports function calling in four steps:

1. Function definition: Provide the list of tools as a JSON object in the system prompt, or use tokenizer.apply_chat_template() with tools=....
2. Function call: By default, LFM2.5 writes Pythonic function calls (a Python list between <|tool_call_start|> and <|tool_call_end|> special tokens), as the assistant answer. You can override this behavior by asking the model to output JSON function calls in the system prompt.
3. Function execution: Execute the call and return the result with the tool role.
4. Final answer: LFM2.5 interprets the tool output and returns a plain-text answer addressing the original prompt.

See the Tool Use documentation for the full guide. Example:

<|startoftext|><|im_start|>system
List of tools: [{"name": "get_candidate_status", "description": "Retrieves the current status of a candidate in the recruitment process", "parameters": {"type": "object", "properties": {"candidate_id": {"type": "string", "description": "Unique identifier for the candidate"}}, "required": ["candidate_id"]}}]<|im_end|>
<|im_start|>user
What is the current status of candidate ID 12345?<|im_end|>
<|im_start|>assistant
<|tool_call_start|>[get_candidate_status(candidate_id="12345")]<|tool_call_end|>Checking the current status of candidate ID 12345.<|im_end|>
<|im_start|>tool
[{"candidate_id": "12345", "status": "Interview Scheduled", "position": "Clinical Research Associate", "date": "2023-11-20"}]<|im_end|>
<|im_start|>assistant
The candidate with ID 12345 is currently in the "Interview Scheduled" stage for the position of Clinical Research Associate, with an interview date set for 2023-11-20.<|im_end|>

Training

LFM2.5-2.6B is pre-trained on ~34T tokens, with a mid-training phase that extends the context window to 128K. Post-training then turns the base model into an agent in four stages: supervised fine-tuning (two rounds), per-domain teacher specialization, multi-domain on-policy distillation, and agentic reinforcement learning.

In particular, agentic reinforcement learning allows us to directly train the model inside popular agentic harnesses. It exposes the model to their tools, system prompts, and interaction patterns, helping it work reliably across agent environments.

🏃 Inference

LFM2.5 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
vLLM	High-throughput production deployments with GPU.	Link
SGLang	High-throughput production deployments with GPU.	Link	—
llama.cpp	Cross-platform inference with CPU offloading.	Link
MLX	Apple's machine learning framework optimized for Apple Silicon.	Link	—
LM Studio	Desktop application for running LLMs locally.	Link	—

[!TIP] ⚡ Faster decoding: attach LFM2.5-2.6B-DSpark, a 328M speculative-decoding drafter, for ~2.6x faster decoding in SGLang and on Apple silicon via Metal with exactly the same outputs.

How to use

LFM2.5-2.6B can be used for direct inference or as a backend for agentic workflows.

Quick start

Get started with Transformers (compatible with transformers>=5.0.0):

from transformers import AutoModelForCausalLM, AutoTokenizer, TextStreamer

model_id = "LiquidAI/LFM2.5-2.6B"
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,
)["input_ids"].to(model.device)

output = model.generate(
    input_ids,
    do_sample=True,
    temperature=0.1,
    top_k=50,
    repetition_penalty=1.1,
    max_new_tokens=512,
    streamer=streamer,
)

Agent Use

LFM2.5-2.6B supports tool calling for agentic workflows. Serve it locally with any OpenAI-compatible backend (see 🏃 Inference, then configure your agent harness to connect to it. For full setup instructions including installation and additional options, see our Agent Harnesses guide.

Note: The port depends on your serving backend — llama.cpp and MLX use 8080, vLLM uses 8000, SGLang uses 30000, and LM Studio uses 1234. Adjust the URLs below accordingly.

Hermes

Either use the interactive wizard or set it directly:

hermes config set model.provider custom
hermes config set model.base_url http://localhost:8080/v1
hermes config set model.default LFM2.5-2.6B
hermes config set model.context_length 131072
hermes config set model.api_mode chat_completions
hermes config set agent.tool_use_enforcement true

OpenClaw

Add to your config to models.providers:

local: {
  baseUrl: "http://localhost:8080/v1",
  apiKey: "sk-local",
  api: "openai-completions",
  models: [{
    id: "LFM2.5-2.6B",
    name: "LFM2.5-2.6B",
    contextWindow: 131072,
    maxTokens: 8192,
    cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 }
  }]
}

Pi

Add to your config to ~/.pi/agent/models.json:

{
  "providers": {
    "local": {
      "baseUrl": "http://localhost:8080/v1",
      "api": "openai-completions",
      "apiKey": "local",
      "models": [{ "id": "LFM2.5-2.6B" }]
    }
  }
}

🔧 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
CPT (Unsloth)	Continued Pre-Training using Unsloth for translation.	Link
SFT (Unsloth)	Supervised Fine-Tuning with LoRA using Unsloth.	Link
SFT (TRL)	Supervised Fine-Tuning with LoRA using TRL.	Link
DPO (TRL)	Direct Preference Optimization with LoRA using TRL.	Link
GRPO (TRL)	GRPO with LoRA using TRL.	Link

📊 Performance

Benchmarks

We compared LFM2.5-2.6B with relevant sub-10B models on a diverse suite of benchmarks.

Benchmark	LFM2.5-2.6B (2.6B)	gemma-4-E2B-it (5.1B)	gemma-4-E4B-it (8B)	Qwen3.5-4B (4.7B)	Qwen3.5-9B (9.7B)
AA-Omni-Public Index	-29.50	-74.47	-49.03	-54.30	-50.43
AA-Omni-Public Acc	8.13	6.37	8.33	17.63	21.30
AA-Omni-Public Non-hallu	59.04	13.67	37.42	12.66	8.84
AIME25	51.87	26.33	34.27	49.33	56.07
LiveCodeBenchv6	59.41	54.92	63.77	60.85	69.86
IFBench	59.17	34.08	39.24	48.40	56.47
Multi-IF	80.07	69.44	77.35	55.67	62.55
IFStruct	85.49	64.85	76.65	36.25	78.50
BFCLv4	56.88	36.98	46.39	50.56	60.13
ToolSandbox	77.83	52.40	65.00	75.55	76.44
τ³-Bench Banking	5.67	3.35	4.12	5.45	5.15
Claw-Eval average (EN)	62.85	53.14	58.02	62.28	66.53
PinchBench	68.22	44.24	55.09	71.26	71.45
BrowseComp+ (OpenClaw)	26.89	8.31	15.90	24.46	27.23

CPU Inference

Due to its efficient LFM2 architecture, LFM2.5-2.6B is the fastest model we tested, with decode speeds of 220 tokens/s on an M5 Max and 113 tokens/s on a Ryzen AI Max+ 395. At 30 tokens/s, it allows you to run capable agents even on a phone.

GPU Inference

LFM2.5-2.6B is the fastest model in its size class, reaching almost 15K output tokens per second at high concurrency, roughly 1.3B tokens per day on a single H100.

📬 Contact

• Got questions or want to connect? Join our Discord community
• If you are interested in custom solutions with edge deployment, please contact our sales team.

Citation

@article{liquidAI202626B,
  author  = {Liquid AI},
  title   = {LFM2.5-2.6B: Agents Everywhere},
  journal = {Liquid AI Blog},
  year    = {2026},
  note    = {www.liquid.ai/blog/lfm2-5-2-6b},
}

@article{liquidai2025lfm2,
  title   = {LFM2 Technical Report},
  author  = {Liquid AI},
  journal = {arXiv preprint arXiv:2511.23404},
  year    = {2025}
}