Results
BrowseWebApp-Bench v2:
Table with columns: Model, Success rate, Relative output-token efficiency| Model | Success rate | Relative output-token efficiency |
|---|
| Qwen/Qwen3.5-4B baseline | 22% | 1.0x |
| This model (SFT, FP8) | 62% | 4.6x |
Training
The source data comprised 3.3k successful executor trajectories and auxiliary browser agent stages. Concise GPT-5.6 Luna reasoning summaries were retained where available.
Table with columns: Setting, Value| Setting | Value |
|---|
| Base model | Qwen/Qwen3.5-4B |
| Method | LoRA supervised fine-tuning |
| Epochs | 2 |
| LoRA rank / alpha | 64 / 128 |
| Effective global batch size | 8 |
Serving With vLLM
The checkpoint was validated with vLLM 0.23.0 using the Qwen reasoning and tool
call parsers:
vllm serve "$MODEL_ID" \
--served-model-name qwen3.5-4b-browser-agent-sft-fp8 \
--tensor-parallel-size 1 \
--max-model-len 262144 \
--reasoning-parser qwen3 \
--enable-auto-tool-choice \
--tool-call-parser qwen3_coder
Recommended Sampling
Use Qwen's recommended precise coding (WebDev) sampling profile:
{
"temperature": 0.6,
"top_p": 0.95,
"top_k": 20,
"min_p": 0.0,
"presence_penalty": 0.0,
"repetition_penalty": 1.0
}