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volosati/Jan-v1-4B
Jan-v1-4B is a text generation model from volosati. Use it when you need the model to write or continue text. It is set up for transformers. The card lists the license as apache-2.0.
[](https://github.com/menloresearch/deep-research) [](https://opensource.org/licenses/Apache-2.0) [](https://jan.ai/)
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From the Hugging Face model README
Jan-v1 is the first release in the Jan Family, designed for agentic reasoning and problem-solving within the Jan App. Based on our Lucy model, Jan-v1 achieves improved performance through model scaling.
Jan-v1 uses the Qwen3-4B-thinking model to provide enhanced reasoning capabilities and tool utilization. This architecture delivers better performance on complex agentic tasks.
For question-answering, Jan-v1 shows a significant performance gain from model scaling, achieving 91.1% accuracy.

The 91.1% SimpleQA accuracy represents a significant milestone in factual question answering for models of this scale, demonstrating the effectiveness of our scaling and fine-tuning approach.
These benchmarks evaluate the model's conversational and instructional capabilities.

Jan-v1 is optimized for direct integration with the Jan App. Simply select the model from the Jan App interface for immediate access to its full capabilities.

Using vLLM:
vllm serve janhq/Jan-v1-4B \
--host 0.0.0.0 \
--port 1234 \
--enable-auto-tool-choice \
--tool-call-parser hermes
Using llama.cpp:
llama-server --model Jan-v1-4B-Q4_K_M.gguf \
--host 0.0.0.0 \
--port 1234 \
--jinja \
--no-context-shift
temperature: 0.6
top_p: 0.95
top_k: 20
min_p: 0.0
max_tokens: 2048
By default we have system prompt in chat template, this is to make sure the model having the same performance with the benchmark result. You can also use the vanilla chat template without system prompt in the file chat_template_raw.jinja.
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