Instructions to use PolarSeeker/ABSeeker-4B-RL with libraries, inference providers, notebooks, and local apps. Follow these links to get started.

Libraries

How to use PolarSeeker/ABSeeker-4B-RL with Transformers:

# Use a pipeline as a high-level helper
from transformers import pipeline

pipe = pipeline("image-text-to-text", model="PolarSeeker/ABSeeker-4B-RL")
messages = [
    {
        "role": "user",
        "content": [
            {"type": "image", "url": "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/p-blog/candy.JPG"},
            {"type": "text", "text": "What animal is on the candy?"}
        ]
    },
]
pipe(text=messages)

# Load model directly
from transformers import AutoProcessor, AutoModelForMultimodalLM

processor = AutoProcessor.from_pretrained("PolarSeeker/ABSeeker-4B-RL")
model = AutoModelForMultimodalLM.from_pretrained("PolarSeeker/ABSeeker-4B-RL", device_map="auto")
messages = [
    {
        "role": "user",
        "content": [
            {"type": "image", "url": "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/p-blog/candy.JPG"},
            {"type": "text", "text": "What animal is on the candy?"}
        ]
    },
]
inputs = processor.apply_chat_template(
	messages,
	add_generation_prompt=True,
	tokenize=True,
	return_dict=True,
	return_tensors="pt",
).to(model.device)

outputs = model.generate(**inputs, max_new_tokens=40)
print(processor.decode(outputs[0][inputs["input_ids"].shape[-1]:]))

Notebooks
Google Colab
Kaggle
Local Apps Settings

vLLM

How to use PolarSeeker/ABSeeker-4B-RL with vLLM:

Install from pip and serve model

# Install vLLM from pip:
pip install vllm
# Start the vLLM server:
vllm serve "PolarSeeker/ABSeeker-4B-RL"
# Call the server using curl (OpenAI-compatible API):
curl -X POST "http://localhost:8000/v1/chat/completions" \
	-H "Content-Type: application/json" \
	--data '{
		"model": "PolarSeeker/ABSeeker-4B-RL",
		"messages": [
			{
				"role": "user",
				"content": [
					{
						"type": "text",
						"text": "Describe this image in one sentence."
					},
					{
						"type": "image_url",
						"image_url": {
							"url": "https://cdn.britannica.com/61/93061-050-99147DCE/Statue-of-Liberty-Island-New-York-Bay.jpg"
						}
					}
				]
			}
		]
	}'

Use Docker

docker model run hf.co/PolarSeeker/ABSeeker-4B-RL

SGLang

How to use PolarSeeker/ABSeeker-4B-RL with SGLang:

Install from pip and serve model

# Install SGLang from pip:
pip install sglang
# Start the SGLang server:
python3 -m sglang.launch_server \
    --model-path "PolarSeeker/ABSeeker-4B-RL" \
    --host 0.0.0.0 \
    --port 30000
# Call the server using curl (OpenAI-compatible API):
curl -X POST "http://localhost:30000/v1/chat/completions" \
	-H "Content-Type: application/json" \
	--data '{
		"model": "PolarSeeker/ABSeeker-4B-RL",
		"messages": [
			{
				"role": "user",
				"content": [
					{
						"type": "text",
						"text": "Describe this image in one sentence."
					},
					{
						"type": "image_url",
						"image_url": {
							"url": "https://cdn.britannica.com/61/93061-050-99147DCE/Statue-of-Liberty-Island-New-York-Bay.jpg"
						}
					}
				]
			}
		]
	}'

Use Docker images

docker run --gpus all \
    --shm-size 32g \
    -p 30000:30000 \
    -v ~/.cache/huggingface:/root/.cache/huggingface \
    --env "HF_TOKEN=<secret>" \
    --ipc=host \
    lmsysorg/sglang:latest \
    python3 -m sglang.launch_server \
        --model-path "PolarSeeker/ABSeeker-4B-RL" \
        --host 0.0.0.0 \
        --port 30000
# Call the server using curl (OpenAI-compatible API):
curl -X POST "http://localhost:30000/v1/chat/completions" \
	-H "Content-Type: application/json" \
	--data '{
		"model": "PolarSeeker/ABSeeker-4B-RL",
		"messages": [
			{
				"role": "user",
				"content": [
					{
						"type": "text",
						"text": "Describe this image in one sentence."
					},
					{
						"type": "image_url",
						"image_url": {
							"url": "https://cdn.britannica.com/61/93061-050-99147DCE/Statue-of-Liberty-Island-New-York-Bay.jpg"
						}
					}
				]
			}
		]
	}'

Docker Model Runner
How to use PolarSeeker/ABSeeker-4B-RL with Docker Model Runner:
```
docker model run hf.co/PolarSeeker/ABSeeker-4B-RL
```

ABSeeker: Training Long-Horizon Search Agents with Answer-Backtracked Credit Assignment

ABSeeker is a long-horizon search agent trained with Answer-Backtracked Credit Assignment (ABC), a fine-grained credit assignment framework that converts sparse trajectory-level outcomes into dense step-level supervision. We trained ABSeeker based on Qwen3.5-4B with only 8.5K training examples and achieved strong performance on long-horizon search benchmarks:

Highlights

Fine-grained credit assignment: ABC rewards useful actions, even in failed trajectories, while suppressing erroneous or redundant actions.
Unified step-level supervision: ABC-SFT reweights the loss of each turn, while ABC-GRPO uses step-level scores as rewards during reinforcement learning.
Strong performance with only 4B parameters: ABSeeker achieves 37.3% on BrowseComp and 39.1% on BrowseComp-ZH, further improving to 55.3% and 52.9% with context management and remaining competitive with substantially larger search agents.