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Nex-N2-Mini-NVFP4

NVFP4 (4-bit) quantized build of Nex-N2-mini — an agentic model with Agentic Thinking.

This repository contains a post-training-quantized checkpoint of nex-agi/Nex-N2-mini, produced with llm-compressor and stored in the compressed-tensors format. The MoE expert stack is quantized to NVFP4 (W4A4) and the attention / output projections to FP8 (W8A8), shrinking the checkpoint from 70.2 GB to 24.8 GB (~2.8×) so the model fits comfortably on a single GPU.

Base model This repository
Weights BF16 NVFP4 + FP8 (mixed precision)
Checkpoint size 70.2 GB 24.8 GB
Minimum GPUs 2× H100 (see Hardware)
Architecture Qwen3_5MoeForConditionalGeneration unchanged

Quantization Details

The model is quantized with compressed-tensors (quant_method: compressed-tensors, format: mixed-precision). The full recipe ships in recipe.yaml.

NVFP4 — W4A4 (nvfp4-pack-quantized)

Applied to the MoE feed-forward stack in layers 0–31 — this is the bulk of the parameters:

  • model.language_model.layers.{0..31}.mlp.experts.{0..255}.{gate,up,down}_proj
  • model.language_model.layers.{0..31}.mlp.shared_expert.{gate,up,down}_proj
Weights Activations
Format FP4 (E2M1), packed 2-per-byte FP4 (E2M1)
Strategy tensor_group, group size 16 tensor_group, group size 16
Block scale dtype float8_e4m3 float8_e4m3
Calibration static, memoryless_minmax dynamic (local), static_minmax global scale

FP8 — W8A8 (float-quantized)

Applied to attention, the linear-attention projections, the LM head, and the MoE stack of the last 8 layers (32–39), which are the most quantization-sensitive:

  • self_attn.{q,k,v,o}_proj
  • linear_attn.{in_proj_qkv,in_proj_z,out_proj}
  • lm_head
  • layers.{32..39}.mlp.experts.*.{gate,up,down}_proj and layers.{32..39}.mlp.shared_expert.{gate,up,down}_proj
Weights Activations
Format FP8 (E4M3) FP8 (E4M3)
Strategy per-channel, symmetric per-token, symmetric
Calibration static, memoryless_minmax dynamic

Kept in BF16

  • The full vision tower (model.visual.*, 333 tensors)
  • MoE routers — mlp.gate, mlp.shared_expert_gate
  • Linear-attention gating / state projections — linear_attn.in_proj_a, linear_attn.in_proj_b, linear_attn.conv1d, A_log, dt_bias, and all linear_attn.norm*
  • Token embeddings and all RMSNorm weights

The KV cache is not quantized (kv_cache_scheme: null).


Hardware

NVFP4 reaches its full speedup on NVIDIA Blackwell GPUs (SM100 / SM120 — B200, GB200, RTX PRO 6000 Blackwell), which have native FP4 tensor cores. vLLM can still load and run this checkpoint on pre-Blackwell hardware through its NVFP4 dequantization/emulation path, in which case you get the memory savings but not the throughput gain.

At 24.8 GB of weights the model serves on a single 80 GB card with room for a long-context KV cache; the launch command below is tuned for that shape.


Usage

Deployment with vLLM

Note: Qwen3.5-MoE support, the NVFP4 compressed-tensors kernels, and the --language-model-only flag all require a recent vLLM build. Use a current release or nightly.

vllm serve /models/Nex-N2-Mini-NVFP4 \
  --served-model-name nex-n2 \
  --host 0.0.0.0 --port 8000 \
  --trust-remote-code --language-model-only \
  --tensor-parallel-size 1 \
  --max-model-len 131072 \
  --max-num-seqs 32 \
  --gpu-memory-utilization 0.60 \
  --max-num-batched-tokens 8192 \
  --enable-chunked-prefill

Flag notes:

  • --language-model-only skips the (unquantized, BF16) vision tower and serves the model as a pure text LLM. Drop it if you want the multimodal path.
  • --max-model-len 131072 is a conservative cap; the checkpoint's max_position_embeddings is 262144.
  • --gpu-memory-utilization 0.60 and --max-num-seqs 32 leave generous headroom — raise them if you have spare VRAM and want more concurrency.
  • --tensor-parallel-size 1 is sufficient at this precision. Increase it for extra KV-cache capacity, not for weight capacity.

Query it through the OpenAI-compatible API:

curl http://localhost:8000/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "nex-n2",
    "messages": [{"role": "user", "content": "Write a Python function that merges overlapping intervals."}],
    "temperature": 0.7,
    "top_p": 0.95,
    "top_k": 40
  }'

Function Calling and Reasoning Parser

Nex-series models emit explicit reasoning traces and support robust function calling. To have vLLM split the reasoning trace from the final answer and parse tool calls into the OpenAI tool_calls schema, add:

  --reasoning-parser qwen3 \
  --tool-call-parser qwen3_coder

Without these flags the reasoning trace and the <tool_call> blocks are returned inline in content, and you parse them yourself.

Recommended Sampling Parameters

  • temperature: 0.7
  • top_p: 0.95
  • top_k: 40

Deployment with SGLang

The base model is best served with the customized sglang fork described in the Nex-N2-mini card. That fork does not currently consume compressed-tensors NVFP4 checkpoints — use the BF16 base model there, and this repository with vLLM.


Performance

The scores below are the published results for the BF16 base models and are reproduced here for reference. They were not re-measured on this NVFP4 checkpoint; expect a small degradation typical of 4-bit post-training quantization. If you benchmark it, we would welcome the numbers in the Community tab.

Benchmark Nex-N2-mini Nex-N2-Pro GPT-5.5 Opus 4.7 Kimi-K2.6 GLM-5.1 MiniMax M3 DeepSeek-V4-Pro
Agent
BrowseComp 74.1 83.7 84.4 79.8 83.2 79.3 83.5 83.4
GDPval 1402 1585 1769 1753 1481 1535 - 1554
Toolathlon 33.3 51.9 55.6 52.8 50.0 40.7 - 51.8
WildClawBench 47.7 53.5 58.2 62.2 - 48.2 - 43.7
WideSearch 62.0 75.6 - - 80.8 - - -
TAU3 65.9 71.1 - - - 70.6 - -
Coding & SWE
SWE-Bench Pro 50.2 58.8 58.6 64.3 58.6 58.4 59.0 55.4
Terminal-Bench 2.1 60.7 75.3 83.4 69.7 - 58.7 66.0 72.0
DeepSWE 8.0 33.6 70 54 24 18 - 8
SWE-Bench Verified 74.4 80.8 82.9 87.6 80.2 - 80.5 80.6
SWE Atlas QnA 31.5 37.9 45.4 45.2 - - 37.9 -
SWE Atlas RF 30.0 32.9 44.8 48.6 - - - -
SWE Atlas TW 23.3 40.0 42.6 38.2 - - 30.8 -
General & Reasoning
GPQA Diamond 82.6 90.7 93.6 94.2 90.5 86.2 - 90.1
IFEval 89.1 94.0 - - 94.5 94.5 - 91.9
Apex 9.4 36.5 - - 24.0 11.5 - 38.3

Nex-N2 Benchmark Overview


About Nex-N2

Nex-N2 is an agent model built for real-world productivity scenarios. With first-tier coding and agentic capabilities, it keeps driving complex, long-horizon tasks forward in real environments to deliver stable, end-to-end results.

Rather than treating reasoning, tool use, and environment execution as separate capabilities, Nex-N2 unifies them through an Agentic Thinking framework that connects requirement understanding, task planning, code implementation, environmental feedback, evaluation and debugging, and continuous iteration into a single closed loop. The framework has two parts:

  • Adaptive Thinking lets the model decide on its own when to think and how deeply — executing simple actions quickly while reasoning thoroughly on critical decisions.
  • Coherent Thinking carries one consistent reasoning paradigm across general reasoning and diverse agentic tasks, staying consistent across tasks and modalities to enable stable capability transfer.

Nex-N2 ships in two variants, both post-trained on the Qwen3.5 series: Nex-N2-Pro (built on Qwen3.5-397B-A17B) and Nex-N2-mini (built on Qwen3.5-35B-A3B-Base).

Model Architecture

Architecture Qwen3_5MoeForConditionalGeneration (hybrid linear + full attention MoE)
Layers 40 (full attention every 4th layer, linear attention elsewhere)
Hidden size 2048
Experts 256, 8 active per token, plus 1 shared expert
Context length 262,144
Vocabulary 248,320

Related Models

License

Released under the Apache 2.0 license, matching the base model.

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