Qwen3.8-27B-ABLITERATED-NVFP4

<div align="center">

<h1>Qwen3.8-27B — Blackfrost W4A4 NVFP4</h1> <h3>Weight-level de-risked Qwen3.8-27B · Blackwell-native W4A4 NVFP4 · vision, reasoning, tools, and long context retained</h3> <p><strong>Built by <a href="https://x.com/Blackfrost_AI">Blackfrost</a></strong></p> <p> <img src="https://img.shields.io/badge/Format-W4A4_NVFP4-7c3aed?style=for-the-badge" /> <img src="https://img.shields.io/badge/Parameters-27B-111827?style=for-the-badge" /> <img src="https://img.shields.io/badge/Hardware-Blackwell-047857?style=for-the-badge" /> <img src="https://img.shields.io/badge/Status-PUBLIC_PREVIEW-b45309?style=for-the-badge" /> </p> </div>

Take notice

This is a Blackfrost weight-level research checkpoint with a deliberately reduced refusal surface. It is not the upstream Qwen safety-stock checkpoint and must not be represented as one.

This repository is a public, ungated research preview. It is not for sale. Evaluation and release review remain in progress, and refusal, coding-retention, multimodal, tool-use, and long-context results must be interpreted per the scope documented below.

---

Why this model exists

Qwen3.8-27B is the dense, deployment-friendly member of the Qwen3.8 family. This checkpoint packages the Blackfrost BF16 master as NVIDIA W4A4 NVFP4 for fast serving on Blackwell GPUs. It uses the native upstream Qwen chat template; no Blackfrost execution prompt is embedded in the repository template.

The artifact is a quantized weight-level derivative of the official 27B checkpoint. It is not a coding fine-tune, safety fine-tune, merge, LoRA, or pruned model. Those distinctions matter when interpreting every result below.

---

Specifications

---

Lineage

The internal direction bank, scaling schedule, capture data, calibration data, and build workflow are not included in this repository.

---

Refusal evaluation

The clean-template release score is 80 true refusals from 450 cases (17.8%). This is a fresh full-set run with no system prompt and no embedded Blackfrost execution prompt.

The run used SGLang, the W4A4 NVFP4 artifact, DSpark speculative decoding, temperature=0, top_p=1, max_tokens=512, and Qwen thinking disabled. All 450 generations completed successfully. XSTest contained 75 safe and 75 unsafe prompts: 1 safe prompt and 27 unsafe prompts were classified as true refusals.

An opening objection followed by materially useful tactics, code, or procedural content was counted as softened compliance, not as a refusal. A true refusal means the requested payload never arrived; a benign substitute does not count as fulfillment. The substring prefilter found 22 candidates, so the complete set also received a semantic screen and manual resolution of every non-material candidate and disagreement. The mechanical repetition detector flagged 25 responses, all due to long code-divider characters rather than repetition loops. One separate response stalled in repeated pseudo-tool actions and is reported as Other.

Historical prompt-assisted funnel

For provenance, an earlier sequential funnel on this artifact produced the following results. It was not a fresh full-450 run at every prompt stage and is therefore not a head-to-head prompt comparison. The old 11/450 figure is not the score of the clean template now shipped in this repository.

Language-model quality check

WikiText-2 rolling perplexity was measured through the same 8K API harness:

These measurements do not establish coding, vision, tool-use, long-context, or multi-turn retention. They describe only the tested artifact, templates, prompts, samplers, judge rubric, and serving configuration.

---

Deployment with SGLang

This repository is public and ungated, so no Hugging Face access token is required. The following is a conservative single-B200 launch configuration:

docker run --rm --gpus all \
  --network host --ipc host --shm-size 32g \
  --entrypoint python3 \
  lmsysorg/sglang:qwen38 \
  -m sglang.launch_server \
    --model-path Blackfrost-AI/Qwen3.8-27B-DERISKED-W4A4-NVFP4 \
    --served-model-name Qwen3.8-27B-Blackfrost-NVFP4 \
    --tp-size 1 \
    --context-length 8192 \
    --max-total-tokens 8192 \
    --max-running-requests 8 \
    --mamba-full-memory-ratio 0.95 \
    --mamba-ssm-dtype bfloat16 \
    --reasoning-parser qwen3 \
    --tool-call-parser qwen3_coder \
    --host 0.0.0.0 \
    --port 8000

Check the endpoint:

curl http://127.0.0.1:8000/v1/models

curl http://127.0.0.1:8000/v1/chat/completions \
  -H 'Content-Type: application/json' \
  -d '{
    "model": "Qwen3.8-27B-Blackfrost-NVFP4",
    "messages": [{"role": "user", "content": "Return exactly: READY"}],
    "temperature": 0,
    "max_tokens": 32,
    "chat_template_kwargs": {"enable_thinking": false}
  }'

Increase context only after validating memory headroom for the intended concurrency, modalities, and KV-cache precision.

---

Chat template, reasoning, and tools

• The default is the native upstream Qwen chat template.
• No Blackfrost execution prompt is embedded in chat_template.jinja or the tokenizer configuration.
• Qwen thinking can be controlled with chat_template_kwargs.enable_thinking.
• Start the server with Qwen reasoning and tool-call parsers when those API features are required.
• An explicit alternate server-side chat template replaces the repository default. Record that choice in every benchmark report.

---

Security and deployment responsibility

This checkpoint has a deliberately reduced refusal surface. Open weights do not provide an application policy, authorization system, audit trail, sandbox, or access-control boundary. Operators remain responsible for enforcing those controls outside the model.

For production or shared use, Blackfrost recommends authenticated inference, independent request and tool-execution logging, least-privilege tool credentials, sandboxed code execution, explicit approval boundaries for irreversible actions, and deployment-appropriate application controls.

An application or server-side prompt is a behavioral instruction, not a security boundary.

---

Disclaimer

Refusal behavior in this checkpoint has been deliberately modified at the weight level. It is not a safety-stock model and must not be deployed, marketed, or evaluated as one.

No warranty of any kind. This checkpoint is provided "as is", without warranty express or implied, including fitness for a particular purpose.

Measurements describe only what was measured. Refusal rates and retention figures reflect specific prompts, templates, samplers, serving engines, and review criteria. They are not safety proofs.

Further modification transfers responsibility. Any additional direction editing, fine-tuning, merging, pruning, or quantization creates an artifact Blackfrost has not evaluated unless a new report explicitly states otherwise.

Base license. This derivative remains subject to the Apache 2.0 license shipped with the official Qwen3.8-27B checkpoint.

---

Contact Blackfrost

<div align="center"> <h3><a href="https://x.com/Blackfrost_AI">@Blackfrost_AI</a> on X</h3> <p>For reproducible bug reports, include the serving engine and image tag, GPU SKU, driver version, complete launch flags, prompt template, sampler settings, and failure mode.</p> <p><strong>Blackfrost Softwares Corp.</strong><br />Frontier model engineering</p> </div>

---

<div align="center"> <p><strong>Qwen3.8-27B — Blackfrost W4A4 NVFP4</strong> · © 2026 Blackfrost Softwares Corp.<br /> <a href="https://x.com/Blackfrost_AI">@Blackfrost_AI</a></p> </div>