Instructions to use OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF with libraries, inference providers, notebooks, and local apps. Follow these links to get started.

Libraries

How to use OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF with llama-cpp-python:

# !pip install llama-cpp-python

from llama_cpp import Llama

llm = Llama.from_pretrained(
	repo_id="OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF",
	filename="LFM2.5-1.2B-Thinking-Q4_K_M.gguf",
)

llm.create_chat_completion(
	messages = "No input example has been defined for this model task."
)

Notebooks
Google Colab
Kaggle
Local Apps

llama.cpp

How to use OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF with llama.cpp:

Install from brew

brew install llama.cpp
# Start a local OpenAI-compatible server with a web UI:
llama-server -hf OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M
# Run inference directly in the terminal:
llama-cli -hf OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M

Install from WinGet (Windows)

winget install llama.cpp
# Start a local OpenAI-compatible server with a web UI:
llama-server -hf OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M
# Run inference directly in the terminal:
llama-cli -hf OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M

Use pre-built binary

# Download pre-built binary from:
# https://github.com/ggerganov/llama.cpp/releases
# Start a local OpenAI-compatible server with a web UI:
./llama-server -hf OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M
# Run inference directly in the terminal:
./llama-cli -hf OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M

Build from source code

git clone https://github.com/ggerganov/llama.cpp.git
cd llama.cpp
cmake -B build
cmake --build build -j --target llama-server llama-cli
# Start a local OpenAI-compatible server with a web UI:
./build/bin/llama-server -hf OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M
# Run inference directly in the terminal:
./build/bin/llama-cli -hf OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M

Use Docker

docker model run hf.co/OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M

LM Studio
Jan
Ollama
How to use OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF with Ollama:
```
ollama run hf.co/OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M
```

Unsloth Studio new

How to use OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF with Unsloth Studio:

Install Unsloth Studio (macOS, Linux, WSL)

curl -fsSL https://unsloth.ai/install.sh | sh
# Run unsloth studio
unsloth studio -H 0.0.0.0 -p 8888
# Then open http://localhost:8888 in your browser
# Search for OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF to start chatting

Install Unsloth Studio (Windows)

irm https://unsloth.ai/install.ps1 | iex
# Run unsloth studio
unsloth studio -H 0.0.0.0 -p 8888
# Then open http://localhost:8888 in your browser
# Search for OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF to start chatting

Using HuggingFace Spaces for Unsloth

# No setup required
# Open https://huggingface.co/spaces/unsloth/studio in your browser
# Search for OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF to start chatting

Pi new

How to use OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF with Pi:

Start the llama.cpp server

# Install llama.cpp:
brew install llama.cpp
# Start a local OpenAI-compatible server:
llama-server -hf OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M

Configure the model in Pi

# Install Pi:
npm install -g @mariozechner/pi-coding-agent
# Add to ~/.pi/agent/models.json:
{
  "providers": {
    "llama-cpp": {
      "baseUrl": "http://localhost:8080/v1",
      "api": "openai-completions",
      "apiKey": "none",
      "models": [
        {
          "id": "OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M"
        }
      ]
    }
  }
}

Run Pi

# Start Pi in your project directory:
pi

Hermes Agent new

How to use OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF with Hermes Agent:

Start the llama.cpp server

# Install llama.cpp:
brew install llama.cpp
# Start a local OpenAI-compatible server:
llama-server -hf OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M

Configure Hermes

# Install Hermes:
curl -fsSL https://hermes-agent.nousresearch.com/install.sh | bash
hermes setup
# Point Hermes at the local server:
hermes config set model.provider custom
hermes config set model.base_url http://127.0.0.1:8080/v1
hermes config set model.default OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M

Run Hermes

hermes

Docker Model Runner
How to use OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF with Docker Model Runner:
```
docker model run hf.co/OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M
```

Lemonade

How to use OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF with Lemonade:

Pull the model

# Download Lemonade from https://lemonade-server.ai/
lemonade pull OpenTransformer/LFM2.5-1.2B-Thinking-Claude-GGUF:Q4_K_M

Run and chat with the model

lemonade run user.LFM2.5-1.2B-Thinking-Claude-GGUF-Q4_K_M

List all available models

lemonade list

LFM2.5-1.2B-Thinking-Claude-High-Reasoning GGUF

GGUF quantizations of DavidAU/LFM2.5-1.2B-Instruct-Thinking-Claude-High-Reasoning.

Quant Details

Quant	Size	BPW
Q8_0	1.19 GB	8.50
Q4_K_M	695 MB	4.98

Original F16: 2.23 GB (16.00 BPW)

About

LiquidAI LFM2.5-1.2B-Instruct fine-tuned with Unsloth on TeichAI/claude-4.5-opus-high-reasoning-250x dataset to produce reasoning traces as plain text (not in thinking blocks).

Reasoning Trace Behavior

Tested with 3 prompts - all produced visible reasoning traces before the final answer. Reasoning appears as plain text, NOT in special thinking/thought blocks.

Tips from the original model card:

Use prompts like "Think carefully..." or "Think deeply before you answer..." to activate reasoning
Regen may be needed to activate reasoning on some prompts
Temp 0.7, rep_pen 1.05, top_p 0.95, min_p 0.05, top_k 40