How to use from the
Use from the
Transformers library
# Use a pipeline as a high-level helper
from transformers import pipeline

pipe = pipeline("text-generation", model="Kaleto/Fallen-Command-111B-NVFP4")
messages = [
    {"role": "user", "content": "Who are you?"},
]
pipe(messages)
# Load model directly
from transformers import AutoTokenizer, AutoModelForCausalLM

tokenizer = AutoTokenizer.from_pretrained("Kaleto/Fallen-Command-111B-NVFP4")
model = AutoModelForCausalLM.from_pretrained("Kaleto/Fallen-Command-111B-NVFP4")
messages = [
    {"role": "user", "content": "Who are you?"},
]
inputs = tokenizer.apply_chat_template(
	messages,
	add_generation_prompt=True,
	tokenize=True,
	return_dict=True,
	return_tensors="pt",
).to(model.device)

outputs = model.generate(**inputs, max_new_tokens=40)
print(tokenizer.decode(outputs[0][inputs["input_ids"].shape[-1]:]))
Quick Links

Fallen-Command-A-111B-v1.1 — NVFP4

NVFP4 (4-bit floating-point, group_size=16) quantization of TheDrummer/Fallen-Command-A-111B-v1.1 — a roleplay/creative finetune of Cohere's Command-A (Cohere2 architecture, 111B). Produced with a custom 3-node heterogeneous distributed pipeline on a personal 2× NVIDIA DGX Spark + RTX 3090 setup. Stored as modelopt NVFP4 weights, served via vLLM's modelopt path.

Cohere2 has a few architectural quirks — tied embeddings, layer_norm_eps, hybrid local/global attention — that needed pipeline-side handling; see Cohere2-specific handling below.


Serving mode on Blackwell (GB10)

On DGX Spark / GB10 with vLLM, this model serves as weight-only FP4: the 4-bit NVFP4 weights are dequantized for each matmul; activations stay BF16. vLLM 0.20.x has no FP4-activation GEMM kernel for Blackwell (sm_120/121), so the NVFP4 path is weight-only regardless of the input_activations field in config.json — on this stack a W4A4-config and a W4A16-config produce bit-identical output. This is the standard, and currently highest-quality, NVFP4 serving mode on Spark. On an FP4-activation-capable stack (TensorRT-LLM, or a future vLLM with a Blackwell FP4 GEMM) the same weights could run as true W4A4.

A practical consequence: because serving is weight-only, the calibration dataset does not affect the served output — the per-tensor weight scales are determined by the weights alone. The calibration pass below is part of the standard modelopt flow but is effectively output-invariant for this serving mode.


Quick facts

Base model TheDrummer/Fallen-Command-A-111B-v1.1 (Cohere Command-A finetune)
Architecture Cohere2ForCausalLM — 64 layers, hidden_size 12288, intermediate 36864, 96 attn heads, 8 KV heads, head_dim 128
Notable arch features Parallel attention/MLP block, hybrid local/global attention (sliding_window 4096, pattern 4), tied input/output embeddings, RoPE θ=50000, 256K max context
Original size ~207 GB (BF16)
Quantized size ~69 GB (14 shards, see Files tab)
Quant format NVFP4 via nvidia-modelopt 0.43.0, group_size=16
lm_head Kept BF16 (unquantized), listed in quantization_config.ignore
Quantized modules 448 Linear layers (64 × 7: q/k/v/o + gate/up/down)
KV cache Configurable at serve time (FP8 recommended)
Calibration 256-sample pass (~25.7 min); see note above on output-invariance
Conversion date 2026-05-22

The hardware: 2× DGX Spark + 1× RTX 3090

The cluster used to produce this artifact:

Node GPU Memory Role
DX10-01 (GB10 Spark) NVIDIA GB10 (sm_121) 128 GB UMA shard0: layers 0–29 + embed_tokens
DX10-02 (GB10 Spark) NVIDIA GB10 (sm_121) 128 GB UMA shard1: layers 30–59
eGPU host (Proxmox VM) NVIDIA RTX 3090 (sm_86) 24 GB VRAM shard2: layers 60–63 + final norm + lm_head

A 30/30/4-layer split keeps each Spark well inside its 128 GB UMA budget while the 3090 handles the tail 4 layers plus the norm and lm_head. Ray RPC carries cross-node hidden states transparently; the Ampere 3090 has no native FP4 hardware but only handles BF16 calibration math, so the architecture mismatch is irrelevant until inference time — the exported NVFP4 file is identical to what an all-Blackwell cluster would produce.

The pipeline is open-source at github.com/KaletoAI/distrib-nvfp4 (Apache 2.0): N-way layer splits via --shard-layers a,b,c, memory-sorted node placement so the smallest-VRAM node gets the smallest shard, and disk-checkpointed phases for resumable runs.


Cohere2-specific handling

Command-A's Cohere2 architecture needed three fixes beyond the standard modelopt NVFP4 flow:

  1. Tied embeddings. Cohere2 sets use_embedding_sharing=true — the output projection reuses model.embed_tokens.weight and the checkpoint has no separate lm_head.weight. The head-bearing shard reconstructs lm_head from embed_tokens so it can be exported (BF16) into the merged model.
  2. Norm epsilon name. Cohere2 names the layernorm epsilon layer_norm_eps (Llama/Mistral use rms_norm_eps); the per-layer export template reads the correct attribute with a fallback.
  3. Generation config. Cohere2's generation_config sets cache_implementation=hybrid, which the 1-layer export template (built with use_cache=False) rejects. It is dropped during per-layer export and the real generation_config is restored in the merged model.

Calibration health-check on the run that produced this artifact — clean, no zero or NaN amax statistics:

  • shard0 (layers 0–29 + embed): good=210, zero=0, nan=0
  • shard1 (layers 30–59): good=210, zero=0, nan=0
  • shard2 (layers 60–63 + norm + lm_head): good=28, zero=0, nan=0

(NVFP4_DEFAULT_CFG inserts 7 weight quantizers per layer.)

After merge, config.json is patched to keep lm_head in quantization_config.ignore, set input_activations.dynamic: true, and inject input_scale=1.0 for every weight quantizer (modelopt 0.43 omits these keys, and vLLM's loader otherwise registers an uninitialized parameter and decodes garbage).


Verification

Loaded and smoke-tested on a single DGX Spark (GB10) with vLLM 0.20.2rc1.dev53FlashInferCutlassNvFp4LinearKernel for the NVFP4 GEMM, FlashInfer attention backend:

  • Model weights occupy ~62.6 GiB; on a 128 GB UMA Spark at gpu-memory-utilization 0.90 this leaves a ~43 GiB KV-cache pool (≈175K tokens at 4K context).
  • All test generations are coherent and accurate — e.g. "The capital of France is""Paris. The area of France is 212,935 square miles…"; "17 + 25""42."

The weight-scale layout was also verified directly: every down_proj.weight_scale is [12288, 2304] (2304 = intermediate 36864 / group_size 16), and there are no stray _quantizer / _double_scale keys — the checkpoint loads with stock vLLM.

A formal throughput benchmark has not been run yet.


Usage

vLLM (serve)

Verified on GB10 with vLLM 0.20.2rc1:

vllm serve /path/to/Fallen-Command-111B-NVFP4 \
  --served-model-name Fallen-Command-111B-NVFP4 \
  --attention-backend flashinfer \
  --dtype auto \
  --kv-cache-dtype fp8 \
  --max-model-len 32768 \
  --max-num-seqs 4 \
  --gpu-memory-utilization 0.90 \
  --enable-chunked-prefill \
  --enable-prefix-caching \
  --port 9007

vLLM auto-detects the modelopt NVFP4 quantization from config.json — no explicit --quantization flag is needed. --gpu-memory-utilization 0.90 leaves enough KV-cache pool for 32K context at max-num-seqs 4 on a 128 GB Spark; drop to 0.85 if you don't need the longer context.

llama-swap entry

"Fallen-Command-111B-NVFP4":
  proxy: "http://127.0.0.1:9007"
  ttl: 0
  checkEndpoint: "/health"
  cmd: >-
    /home/<user>/vllm-env/bin/python3 -m vllm.entrypoints.openai.api_server
    --model /home/<user>/models/Fallen-Command-111B-NVFP4
    --served-model-name Fallen-Command-111B-NVFP4
    --attention-backend flashinfer
    --dtype auto
    --kv-cache-dtype fp8
    --max-model-len 32768
    --max-num-seqs 4
    --gpu-memory-utilization 0.90
    --enable-chunked-prefill
    --enable-prefix-caching
    --port 9007
    --host 127.0.0.1

Prompt format

Use the Cohere / Command chat template (it ships in tokenizer_config.json, so apply_chat_template and vLLM's OpenAI server handle it automatically). See TheDrummer's original card for finetune-specific usage notes.


Files in this repository

  • model-NNNNN-of-00014.safetensors — 14 shards, NVFP4-packed weights + scales (~69 GB total)
  • model.safetensors.index.json — weight map (1859 keys: 448 quantized linears × 3 scale/weight keys + injected input_scale keys + 64 layernorms + embed + lm_head)
  • config.json — Cohere2 config with quantization_config.ignore=["lm_head"] and input_activations.dynamic: true
  • hf_quant_config.json, generation_config.json — auxiliary modelopt + generation configs
  • tokenizer.json, tokenizer_config.json, special_tokens_map.json — Command-A tokenizer, untouched from upstream

Acknowledgments

  • TheDrummer for the Fallen-Command-A-111B finetune
  • Cohere / Cohere Labs for the Command-A base model and the Cohere2 architecture
  • NVIDIA for the DGX Spark / GB10 platform, the NVFP4 format, and modelopt
  • vLLM project for modelopt NVFP4 inference support

License

This NVFP4 quantization inherits the license of the base model TheDrummer/Fallen-Command-A-111B-v1.1, which is derived from Cohere's Command-A — released under CC-BY-NC 4.0 with Cohere's Acceptable Use Policy. For research, evaluation, and personal non-commercial use only.


Status

Single-author release. Feedback welcome — on the model artifact (vLLM behaviour, sampling, RP quality) and on the pipeline that built it.

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