---
license: apache-2.0
base_model: Cloudflare/clef-flash
base_model_relation: quantized
library_name: vllm
tags:
- clef
- systemone
- jev
- fp8
- compressed-tensors
- llm-compressor
- vllm
- qwen3.5
- structured-output
- classification
---

# clef-flash-FP8-Dynamic

**Unofficial** FP8_DYNAMIC quantization of [Cloudflare/clef-flash](https://huggingface.co/Cloudflare/clef-flash),
a 9B decision model that scores every option of every typed question (choice / score / true-false)
in one forward pass. This repo is not affiliated with or endorsed by Cloudflare.

It ships with a small **vLLM plugin** and a **Jev/SystemOne-compatible HTTP server** (`POST /v1/systemone`),
because stock vLLM cannot run Clef's custom joint-schema head. In short: near-lossless (98.8% top-1 agreement with BF16) and 1.5x BF16's two-GPU throughput on a single GPU.

> [!IMPORTANT]
> **Read before using**
> - **Text and JSON state only.** The vision tower is kept in BF16 in the checkpoint but has **not been tested**;
>   the server rejects `images` / `videos` with HTTP 400 and runs vLLM with the vision tower disabled.
> - **Use the bundled vLLM plugin.** The quantized checkpoint does not run efficiently in plain `transformers`
>   (it can only be dequantized to BF16, which removes the memory and speed benefit). The plugin is pinned to
>   **vLLM 0.28.x**; it uses vLLM pooling internals that may change in later versions.
> - **Hardware:** **NVIDIA Ada, Hopper or Blackwell** (SM 8.9+: L4, L40S, RTX 40/50-series, H100/H200, B200).
> - **Tested on one setup only:** 2x RTX 5070 Ti 16 GB (SM 12.0, PCIe, no NVLink), vLLM 0.28.0, CUDA 13.
> - **Evaluated on 1,400 records from 7 public tasks** with our own harness (below), not on Cloudflare's Decision Index.
>   Expect a similar but not identical picture on your data; check your own workload before relying on it.

## Quickstart: SystemOne API server

```bash
hf download kurcontko/clef-flash-FP8-Dynamic --local-dir clef-flash-FP8-Dynamic

docker run --gpus all --ipc=host -p 8000:8000 -v $PWD/clef-flash-FP8-Dynamic:/model:ro \
  --entrypoint bash vllm/vllm-openai:v0.28.0 -c \
  "cp -r /model/vllm_plugin /tmp/p && pip install -q /tmp/p && clef-systemone --model /model --dp 1"
```

`--dp N` runs one engine per GPU behind the one port (recommended over tensor parallelism on PCIe GPUs).
The server warms up its kernels before `/health` reports ready (about 3-4 minutes from a cold container).

```bash
curl localhost:8000/v1/systemone -H 'content-type: application/json' -d '{
  "model": "clef-flash",
  "state": "Our checkout started returning errors and orders are blocked.",
  "questions": {
    "department": {"type": "choice", "instructions": "Which team should handle the message?",
                   "criteria": {"billing": "Payments or invoices", "technical": "Bugs or outages"}},
    "urgency": {"type": "score", "criteria": ["Can wait", "This week", "Today"]},
    "outage": {"type": "noul", "instructions": "Is a service down?"}}}'
```

The request and response bodies are the same as the `systemone()` function in the original release:
`answers` keyed by question ID (`choice` with `confidence` and `probabilities`, `score` with the expected `score`
and `legend`, `noul` with the probability of true) and `usage`. Also served: `GET /v1/models`, `GET /health`.

## Quickstart: Python (offline vLLM)

```python
# pip install ./clef-flash-FP8-Dynamic/vllm_plugin   (in an environment with vllm==0.28.*)
import sys
from transformers import AutoTokenizer
from vllm import LLM, PoolingParams
from clef_vllm import ARCHITECTURE, TASK, schema_layout

path = "./clef-flash-FP8-Dynamic"
sys.path.insert(0, path)
from joint_schema_model import encode_record


def main():
    # Keep `llm` local: vLLM shuts its engine process down when the LLM object is freed.
    llm = LLM(model=path, hf_overrides={"architectures": [ARCHITECTURE]}, runner="pooling",
              enable_prefix_caching=False, language_model_only=True, max_model_len=16384)
    tokenizer = AutoTokenizer.from_pretrained(path)
    record = {
        "state": {"invoice": {"vendor": "Acme", "total": 1250.0, "currency": "USD", "status": "overdue"}},
        "questions": {
            "status": {"type": "choice", "instructions": "What is the invoice status?",
                       "criteria": {"paid": "Invoice is paid.", "overdue": "Invoice is past due.", "draft": "Not sent."}},
            "large": {"type": "noul", "instructions": "Is the total above 1000 USD?"},
        },
    }
    encoded = encode_record(tokenizer, record)
    params = PoolingParams(task=TASK, extra_kwargs={"clef_questions": schema_layout(encoded)})
    output = llm.encode([{"prompt_token_ids": list(encoded.input_ids)}], pooling_params=[params], pooling_task=TASK)[0]

    logits, offset = output.outputs.data.float(), 0   # every option logit of every question, in order
    for question in encoded.questions:
        n = len(question.option_ids)
        print(question.question_id, dict(zip(question.option_ids, logits[offset:offset + n].softmax(-1).tolist())))
        offset += n


if __name__ == "__main__":
    main()
```

Pass a list of prompts and a matching list of `PoolingParams` to score many records in one call; vLLM batches them.

## Results

### Accuracy and agreement with BF16

1,400 records, 200 per task, from held-out splits: BANKING77 (test), ARC-Challenge (test), MMLU (test),
HellaSwag (validation), ANLI R3 (test), BoolQ (validation), and a multi-question ANLI R1 set (3 questions per
record: choice + true/false + score). **Accuracy** is against gold labels. **Agree** is top-1 agreement with the
BF16 model and **KL** is mean KL(BF16 ‖ quantized) per question. BF16 is the original release run with
`transformers` 5.10.2; the quantized rows were measured in vLLM with real FP8/FP4 kernels.

| Task | BF16 acc | FP8 acc | FP8 agree | FP8 KL | NVFP4 acc | NVFP4 agree | NVFP4 KL |
|---|---:|---:|---:|---:|---:|---:|---:|
| BANKING77 (77-way intent) | 96.5 | 97.0 | 99.5 | 0.0005 | 97.5 | 98.0 | 0.013 |
| ARC-Challenge | 99.5 | 99.5 | 100.0 | 0.0006 | 99.0 | 99.5 | 0.009 |
| MMLU | 94.5 | 95.0 | 99.5 | 0.0035 | 93.5 | 95.5 | 0.026 |
| HellaSwag | 99.0 | 99.0 | 100.0 | 0.0003 | 99.0 | 100.0 | 0.002 |
| ANLI R3 | 50.0 | 49.5 | 97.5 | 0.0028 | 49.0 | 86.5 | 0.041 |
| BoolQ | 87.5 | 88.5 | 99.0 | 0.0026 | 87.5 | 98.0 | 0.018 |
| Multi-question ANLI R1 | 73.0 | 74.0 | 98.0 | 0.0023 | 71.5 | 90.3 | 0.034 |
| **All** | **84.1** | **84.6** | **98.8** | **0.0019** | **83.6** | **94.3** | **0.024** |

Accuracy differences of under 1 point are within noise at 200 records per task. The BF16 model run through the same
plugin in vLLM agrees with `transformers` on 99.8% of questions (KL 0.0001), so the plugin itself adds no error.
NVFP4 moves most on hard, near-chance cases (ANLI): treat its confidences on borderline inputs with care.

### Throughput

Same 1,400 records (717k tokens, ~512 per record), RTX 5070 Ti 16 GB GPUs.

| Setup | GPUs | Records/s | Tokens/s | vs BF16 transformers |
|---|---:|---:|---:|---:|
| BF16, `transformers` 5.10.2 (original release code, model split over 2 GPUs) | 2 | 6.1 | 3,113 | 1.0x |
| BF16, vLLM + plugin, tensor parallel 2 | 2 | 13.0 | 6,633 | 2.1x |
| **FP8**, vLLM + plugin | 1 | 19.5 | 9,986 | 3.2x |
| **NVFP4**, vLLM + plugin | 1 | 39.8 | 20,359 | 6.5x |
| FP8, one engine per GPU (`--dp 2`) | 2 | ~39 | ~20,000 | 6.4x |
| NVFP4, one engine per GPU (`--dp 2`) | 2 | ~81 | ~41,000 | 13x |

Through the HTTP server with 64 concurrent clients: NVFP4 on 1 GPU 39.7 req/s (p50 0.95 s, p95 5.1 s),
NVFP4 on 2 GPUs 78.7 req/s; with 8 concurrent clients on 2 GPUs, p50 latency is 132 ms. On PCIe GPUs, tensor
parallelism was slower than one engine per GPU (FP8 TP2: 8,605 tok/s; NVFP4 TP2: 10,850 tok/s).

## Quantization details

- **Tool:** llm-compressor 0.14.0 (compressed-tensors 0.19.0), `QuantizationModifier(targets="Linear", scheme="FP8_DYNAMIC")`.
- **Scheme:** FP8 (E4M3) W8A8: per-output-channel static weight scales, per-token dynamic activation scales.
- **Calibration:** None needed (weight scales from the weights, activation scales computed per token at runtime).
- **Kept in BF16:** `lm_head` (the joint head reads its rows as lexical option embeddings, so it is never quantized),
  the vision tower (`model.visual.*`), the Gated DeltaNet gate projections `linear_attn.in_proj_a` / `in_proj_b`
  (32 outputs each), embeddings, norms, and the joint schema head (`clef_head/`).
- **Gated DeltaNet fused scale:** vLLM fuses `linear_attn.in_proj_qkv` and `in_proj_z` into one GEMM, which needs a
  shared NVFP4 weight global scale. llm-compressor 0.14 only shares scales for q/k/v and gate/up, so
  `scripts/quantize.py` adds `("in_proj_qkv", "in_proj_z")` to its fused groups. Without this, vLLM applies the
  larger scale to both halves and the qkv weights come out scaled by about 0.67 (we measured 92.9% instead of 94.3%
  agreement). Anyone re-quantizing Qwen3.5-family models to NVFP4 for vLLM should do the same.
- `recipe.yaml` is the exact recipe llm-compressor saved.

## How the vLLM plugin works

`vllm_plugin/` (`pip install`-able, package `clef-vllm`) registers `ClefFlashForDecision`, a subclass of vLLM's
`Qwen3_5ForConditionalGeneration` that runs as a pooling model. Its pooler collects each request's final hidden
states across chunked prefill and runs the original `JointSchemaHead` (from `joint_schema_model.py`) on the full
prompt. Each request carries its schema layout (question and option token spans from `encode_record`) in
`PoolingParams.extra_kwargs["clef_questions"]`; the output is one flat vector of every option logit. Prefix caching
must be off. Under tensor parallelism the vocab-sharded `lm_head` is gathered once on rank 0 for the head's lookups.

## Files

| Path | Purpose |
|---|---|
| `model.safetensors`, `config.json`, `recipe.yaml` | Quantized backbone (12 GB, compressed-tensors format) |
| `clef_head/` | Joint schema head, BF16, unchanged from the original release (in a subfolder so vLLM does not load it as backbone weights) |
| `joint_schema_model.py` | Original release code: `encode_record`, `systemone_answer`, the head module (unchanged) |
| `tokenizer*.json`, `chat_template.jinja`, `processor_config.json`, `generation_config.json` | Tokenizer and processor (unchanged) |
| `vllm_plugin/` | vLLM plugin and `clef-systemone` server |
| `scripts/` | `build_data.py` (calibration/eval sets) and `quantize.py` (how this checkpoint was made) |

See also [kurcontko/clef-flash-NVFP4](https://huggingface.co/kurcontko/clef-flash-NVFP4) (2x faster again, about -0.5 points).

## License and attribution

Apache-2.0, following [Cloudflare/clef-flash](https://huggingface.co/Cloudflare/clef-flash) (itself post-trained from
[Qwen/Qwen3.5-9B](https://huggingface.co/Qwen/Qwen3.5-9B)). All credit for the model goes to its original authors; this
repository only adds the quantization, the vLLM plugin and the server. Not an official Cloudflare release.