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Quantized Export

Seth HobsonCommunityCreated by Seth Hobson

  • Skill
  • Workflow
  • Cloud and DevOps
  • MIT
  • Low risk

From the author

Export a promoted fine-tuned model in the right deployment format — merged safetensors, LoRA-only, GGUF with imatrix, or FP8. Use after a checkpoint passes promotion, when choosing a quantization format for a target device, or when an exported model fails its smoke test.
— the description by Seth Hobson

From the skill’s files

Taken from the skill’s own files (its description, section headings and stated usage). Not an AutoGineer summary, and not written by the author as one.

Export a promoted fine-tuned model in the right deployment format — merged safetensors, LoRA-only, GGUF with imatrix, or FP8. Use after a checkpoint passes promotion, when choosing a quantization format for a target device, or when an exported model fails its smoke test. The last stop after checkpoint-promotion hands off a PROMOTE verdict: a checkpoint that cleared the four-stage gate still isn't deployed until it's exported in the right format for its target runtime and proven to still work post-export. A REJECT verdict never reaches this skill — export starts only from a promoted checkpoint.

What it does

  • Format Map
  • Workload Overrides
  • The Smoke Test

When to use it

The skill’s files do not state this.

Advantages

The skill’s files do not state this.

Usage examples

The skill’s files do not state this.

Install

  1. Download the skill as a ZIP:

    https://mp-staging.autogineer.com/agent-skills/wshobson/quantized-export/download
  2. Unzip it into the cross-client skills folder of your project:

    mkdir -p .agents/skills && unzip quantized-export.zip -d .agents/skills

Documentation by Seth Hobson

Quantized Export

The last stop after checkpoint-promotion hands off a PROMOTE verdict: a checkpoint that cleared the four-stage gate still isn't deployed until it's exported in the right format for its target runtime and proven to still work post-export. A REJECT verdict never reaches this skill — export starts only from a promoted checkpoint.

Input: a promoted checkpoint (or LoRA adapter) plus the target deployment surface — GPU class, serving stack, and whether long-context/code/math workloads are in scope. Output format: an exported artifact in the chosen format plus a smoke-test diff report comparing 3–5 golden outputs pre-export and post-export.

Format Map

Pick format by hardware and deployment shape, not by habit — the wrong pick either wastes throughput headroom or breaks silently on specific workloads (see Workload Overrides).

  • FP8 is the default on Hopper-class GPUs and newer. It preserves near-bf16 quality at roughly half the memory, and it's the safe first choice whenever the target GPU supports it and no edge-device constraint applies.

  • AWQ INT4 targets older GPUs that predate FP8 hardware support. GPTQ is superseded for new deployments — don't reach for it on a fresh export; AWQ has better accuracy retention at the same bit width and wider current tooling support.

  • GGUF with Q4_K_M quantization, built from an imatrix, is the edge/llama.cpp format. Use it for local or CPU-adjacent deployment, not for GPU-serving throughput — it optimizes for footprint, not tokens/sec on a datacenter GPU.

  • NVFP4 is for Blackwell-at-scale deployments only — and explicitly NOT on GB10. NVFP4 on SM121 (GB10) runs ~32% slower than FP8 because the hardware lacks a native cvt.e2m1x2 path unless the kernel is compiled sm_121a. Choosing NVFP4 on a GB10 target is a regression, not an upgrade — pick FP8 there instead.

  • Merged vs. LoRA-only is a separate axis from quant format. A merged export folds the adapter into the base weights: larger artifact, no base-model dependency at serve time. LoRA-only keeps the adapter separate: much smaller artifact, but the serving stack must load the exact same base model alongside it — a mismatched or wrong-revision base silently changes outputs. Pick merged when artifact portability matters more than storage; pick LoRA-only when disk footprint or multi-adapter serving matters more.

Worked Picks

The core format-selection tradeoff, read as a lookup table for common scenarios:

TargetWorkloadFormat
Datacenter GPUgeneric chatFP8
Datacenter GPUlong-context/code/mathFP8 or W8A8 — never INT4
Older GPU generationgenericAWQ INT4
Edge device / laptopllama.cpp servingGGUF Q4_K_M + imatrix
GB10any workloadFP8 via vLLM nightly, or GGUF via llama.cpp locally — skip NVFP4
# quick decision snippet — see the table above for the full map
hopper_or_newer: fp8
older_gpu: awq-int4
edge_llama_cpp: gguf-q4_k_m+imatrix
gb10_any_workload: fp8-vllm-nightly   # never nvfp4 on GB10

Workload Overrides

The Format Map above is a default, not a rule that survives every workload. Long-context, code, and math workloads break at INT4 — quantization error compounds across long sequences and precise token-level reasoning in ways that don't show up on short, generic prompts. For any of these three workload classes, stay on FP8 or W8A8 even if the target hardware would otherwise justify INT4 on cost grounds.

  • Don't validate this override with MMLU or similar broad-knowledge benchmarks — they don't stress the failure mode. Measure with the actual task evals — the goldens and graders from eval-harness-first, run through the exported artifact — because INT4 degradation on long-context, code, or math shows up as task-specific failures (dropped context, broken syntax, arithmetic errors) well before it moves a knowledge benchmark.

  • If a task eval regresses after an INT4 export on one of these three workload classes, the fix is switching format, not re-tuning the quantization recipe — AWQ and GPTQ variants at the same bit width share the same compounding-error failure mode on these workloads.

The Smoke Test

Export bugs are silent at the file level — a malformed export still produces a loadable artifact, so file-existence checks prove nothing. The smoke test is mandatory for every export, with no exception for a format that "should just work":

  1. Load the exported artifact in its actual target runtime — vLLM for FP8/AWQ, llama.cpp for GGUF, not a quick sanity load in a different framework than the one that will serve it in production.

  2. Run 3–5 golden prompts through it — pull these from the same eval/goldens.jsonl eval-harness-first maintains, not a fresh ad hoc set.

  3. Compare each output against the pre-export generation for the same prompt, same deterministic sampling settings — greedy decoding (temperature 0) and a fixed seed, persisted and reused between the pre- and post-export runs, not just nominally identical config. For a lossless export, byte match is the gate — any diff is a bug. For a lossy (quantized) export, byte match is expected to fail; the gate is task-grader verdict agreement instead — see references/export-commands.md's Smoke-Test Script Skeleton.

Run this as a gate, not a manual check:

python smoke_test.py "$EXPORT_PATH" \
    eval/goldens.jsonl pre-export-outputs.jsonl
# non-zero exit on any pre/post mismatch
Failure Signatures

What export bugs actually look like, not a clean pass/fail flag:

  • Template mismatch presents as garbled or run-on output — the chat template baked into the export doesn't match the one the checkpoint was trained and evaluated against, so turn boundaries or special tokens land in the wrong place.

  • Wrong quantization applied to lm_head presents as off-template or semantically nonsensical output that still looks fluent — the output head lost precision it needed even though the rest of the network quantized cleanly.

Never ship an export that skipped this step — a checkpoint's PROMOTE verdict says the un-exported checkpoint is good; it says nothing about the export pipeline. Re-run on any quant-method or runtime version bump, not only after the first export. Runnable command sequences for every format plus the smoke-test script skeleton: references/export-commands.md.

  • checkpoint-promotion — the only valid upstream source for this skill. A checkpoint without a PROMOTE verdict doesn't reach export.

  • eval-harness-first — owns the eval/goldens.jsonl this skill's smoke test draws its 3–5 prompts from, and the task evals the Workload Overrides section requires for long-context/code/math validation.

  • finetuning-method-selection — its references/model-catalog.md is the place to check hardware-class assumptions (which GPU generations a base model targets) before picking a format off the Format Map above.

Spark users: on GB10, GGUF via llama.cpp works well for local serving, and FP8 serving via vLLM nightly builds is the other proven path — NVFP4 is the one format to avoid there (see the Format Map exception above). Once the dgx-spark-ops plugin is installed, defer Spark-specific serving and thermal questions to its skills rather than re-deriving them here.

Files

references/export-commands.md

Last verified: 2026-07-14

Export Commands

Complete command sequences for every format on the SKILL.md Format Map, plus the smoke-test script skeleton. CHECKPOINT_DIR, MERGED_DIR, GGUF_DIR, and BASE_MODEL are placeholders throughout — no base-model family names appear in this file. Fill each with the promoted checkpoint's actual path/repo before running.

Unsloth: Merged Safetensors

Merged export folds the LoRA adapter into the base weights — use this path when the serving stack needs a single self-contained artifact (see SKILL.md's merged-vs-LoRA-only tradeoff).

from unsloth import FastLanguageModel

model, tokenizer = FastLanguageModel.from_pretrained(
    model_name=CHECKPOINT_DIR,
    max_seq_length=4096,
    load_in_4bit=False,  # load full precision before merge
)

# fp16/bf16 merged export — safe default, no quant loss at this step
model.save_pretrained_merged(
    MERGED_DIR,
    tokenizer,
    save_method="merged_16bit",
)

# 4-bit merged export — only if the serving stack
# consumes bitsandbytes 4-bit directly (rare; most
# deployments quantize downstream instead — see the
# AWQ and GGUF sections below)
model.save_pretrained_merged(
    MERGED_DIR + "-4bit",
    tokenizer,
    save_method="merged_4bit",
)

Unsloth: GGUF with Quant Method

Unsloth can drive llama.cpp's converter and quantizer directly. The quantization_method argument accepts a list — pass every quant level needed for target devices in one call to avoid re-converting from safetensors each time:

model.save_pretrained_gguf(
    GGUF_DIR,
    tokenizer,
    quantization_method=["q4_k_m", "q8_0"],
)

q4_k_m is the edge default from the Format Map; q8_0 is a higher-fidelity fallback for validating that a quality regression traces to the quant level rather than the conversion itself — export both when in doubt, compare smoke-test diffs, then ship only the one actually deployed.

llama.cpp: Build, Convert, imatrix + Quantize

Verified against llama.cpp commit b1-6e52db5, built from source on aarch64/GB10. Three corrections against older guidance floating around for this tool, found the hard way:

Build with the default configuration — do not try to build "just the tools you need." cmake --build --target llama-cli llama-quantize fails ("No rule to make target"), and configuring with -DLLAMA_BUILD_EXAMPLES=OFF -DLLAMA_BUILD_SERVER=OFF breaks the default build outright — the unified llama app links against llama-cli-impl/llama-server-impl libraries those flags disable. Full default build is cheap enough (~2 min at -j20 on a 20-core aarch64 box) that a minimal-target build isn't worth the breakage risk:

cmake -B build
cmake --build build --config Release -j"$(nproc)"

Converter prerequisites — neither is optional:

pip install ./gguf-py
pip install sentencepiece

convert_hf_to_gguf.py needs the repo's own gguf-py package installed, and imports sentencepiece unconditionally on the tokenizer path — even for a BPE-tokenizer model that the converter otherwise handles natively.

# 1. Convert HF safetensors to GGUF (f16, no quant yet)
python convert_hf_to_gguf.py \
    "$MERGED_DIR" \
    --outfile "$GGUF_DIR/model-f16.gguf" \
    --outtype f16

# 2. Generate the importance matrix from a calibration
#    corpus — domain-representative text, several
#    hundred KB minimum; a generic corpus (e.g. the
#    llama.cpp wikitext sample) works if no
#    domain corpus is available
./llama-imatrix \
    -m "$GGUF_DIR/model-f16.gguf" \
    -f calibration-corpus.txt \
    -o "$GGUF_DIR/imatrix.dat" \
    --chunks 200

# 3. Quantize using the imatrix — Q4_K_M is the
#    edge/llama.cpp default from the Format Map
./llama-quantize \
    --imatrix "$GGUF_DIR/imatrix.dat" \
    "$GGUF_DIR/model-f16.gguf" \
    "$GGUF_DIR/model-Q4_K_M.gguf" \
    Q4_K_M

Skipping the imatrix step (quantizing straight from f16) works but leaves accuracy on the table at Q4_K_M — the imatrix step is cheap relative to the training run that produced the checkpoint and should not be skipped for a production export.

Raw-prompt smoke testing: use llama-completion, not llama-cli. Current llama-cli is a chat-first UI — it re-templates -p text as a conversation turn and, at the end of generation, drops into an interactive > prompt loop regardless of -no-cnv (the flag still parses and appears in --help, but does nothing the newer --single-turn flag doesn't already own; with stdin closed, a script invoking llama-cli -no-cnv hangs indefinitely instead of exiting). The raw, non-chat completion behavior a smoke test needs lives in a separate binary:

./llama-completion \
    -m "$GGUF_DIR/model-Q4_K_M.gguf" \
    -p "$(cat prompt.txt)" \
    -n 512 --temp 0 --seed 0

llama-completion exits after generating, does not re-template the prompt, and does not require a -no-cnv/--single-turn flag at all — it never enters chat mode in the first place.

AWQ Export Sketch

AWQ targets older GPU generations per the Format Map. Sketch using the autoawq package against the merged safetensors directory:

from awq import AutoAWQForCausalLM
from transformers import AutoTokenizer

quant_config = {
    "zero_point": True,
    "q_group_size": 128,
    "w_bit": 4,
    "version": "GEMM",
}

model = AutoAWQForCausalLM.from_pretrained(MERGED_DIR)
tokenizer = AutoTokenizer.from_pretrained(MERGED_DIR)

# calibration data: a few hundred domain-representative
# samples; reuses the same calibration-corpus concept
# as the llama.cpp imatrix step above
model.quantize(tokenizer, quant_config=quant_config)
model.save_quantized(MERGED_DIR + "-awq")
tokenizer.save_pretrained(MERGED_DIR + "-awq")

Do not run this path on a checkpoint destined for a long-context, code, or math workload — per SKILL.md's Workload Overrides, stay on FP8/W8A8 for those regardless of target GPU generation.

vLLM: FP8 Load Check

FP8 is the Format Map default on Hopper-class GPUs and newer. Confirm the serving stack actually loads the export in FP8 before treating the export as done — a silent fallback to bf16 defeats the memory savings without erroring:

vllm serve "$MERGED_DIR" \
    --quantization fp8 \
    --served-model-name checkpoint-fp8 \
    --port 8000 > vllm-fp8-load.log 2>&1 &
VLLM_PID=$!

# Bounded wait for readiness — up to 60s, not a blind sleep.
ready=0
for _ in $(seq 1 30); do
    if curl -sf http://localhost:8000/v1/models | grep -q checkpoint-fp8; then
        ready=1
        break
    fi
    sleep 2
done

if [ "$ready" -ne 1 ]; then
    echo "FAILED: endpoint did not come up within 60s"
    kill "$VLLM_PID" 2>/dev/null
    exit 1
fi

# Endpoint liveness alone does not prove FP8 loaded — vLLM can
# silently fall back to bf16. Confirm the actual dtype from the
# startup log before trusting the deployment.
if grep -qi 'fp8' vllm-fp8-load.log; then
    echo "FP8 endpoint up and confirmed FP8 in startup log"
else
    echo "FAILED: endpoint up but startup log does not confirm FP8 (possible silent bf16 fallback)"
    kill "$VLLM_PID" 2>/dev/null
    exit 1
fi

Use a nightly vLLM build for GB10/SM121 targets per SKILL.md's Spark note — the SM121 fix for FP8 serving landed in the nightly channel, not yet in a stable release as of the date at the top of this file.

Smoke-Test Script Skeleton

Load → generate on goldens → diff report, per SKILL.md's mandatory Smoke Test section. This skeleton is runtime-agnostic — swap the load() and generate() bodies for the target stack (vLLM client, llama.cpp Python bindings, AWQ loader) without changing the surrounding structure.

The comparison mode depends on whether the export is lossless or lossy — pick before running:

  • Lossless exports (fp16/bf16 merge, no quantization) — byte/string match (pre.strip() == post.strip()) is the correct gate. Any divergence here is a bug, full stop.

  • Lossy exports (any quantized format — Q4_K_M, AWQ INT4, FP8) — byte match is unmeetable by design, not a signal of a bug. A quantized checkpoint legitimately perturbs logits, so 0/5 exact matches with 5/5 schema-valid, on-template outputs is the expected healthy result for a lossy export. The gate for a lossy export is the task grader's verdict, per SKILL.md's Workload Overrides section — run each golden's actual grader (from eval-harness-first) against both the pre- and post-export output, and diff verdicts, not text. A byte-match diff is still worth logging for triage (it tells you how much the output changed), but it must never gate a lossy export by itself.

import json
import sys

# Deterministic decoding, persisted and reused for both the
# pre-export run (that produced pre-export-outputs.jsonl) and the
# post-export run below — greedy (temperature 0) with a fixed seed.
# Any drift in these settings between the two runs can flip an
# otherwise-valid export into a spurious mismatch.
SMOKE_TEST_GENERATION_KWARGS = {"temperature": 0, "seed": 0, "max_new_tokens": 512}

def load_pre_export_outputs(path: str) -> dict:
    """goldens.jsonl-keyed pre-export generations,
    produced from the promoted checkpoint before any
    quantization/export step, using
    SMOKE_TEST_GENERATION_KWARGS."""
    with open(path) as f:
        return {row["task_id"]: row["output"] for row in map(json.loads, f)}

def load_goldens(path: str, n: int = 5) -> list:
    with open(path) as f:
        rows = [json.loads(line) for line in f]
    return rows[:n]

def load_exported_model(export_path: str):
    """Load in the ACTUAL target runtime — vLLM,
    llama.cpp, or the AWQ loader. Never substitute
    a different framework than production here."""
    raise NotImplementedError("wire to target runtime")

def generate(model, prompt: str, **generation_kwargs) -> str:
    raise NotImplementedError("wire to target runtime")

def grade(task_id: str, output: str) -> bool:
    """Run the golden's actual task grader (from
    eval-harness-first) against a single output.
    Wire to the real grader module — never stub this
    with a byte-match; that defeats the point of the
    lossy-export path below."""
    raise NotImplementedError("wire to eval-harness-first's grader for this golden")

def diff_report(golden_id: str, pre: str, post: str, *, lossless: bool) -> dict:
    """lossless=True: gate on byte/string match.
    lossless=False (any quantized format): gate on
    grader verdict agreement — byte match is expected
    to fail for a healthy lossy export, so it is
    recorded for triage only, never as `match`."""
    byte_match = pre.strip() == post.strip()
    if lossless:
        match = byte_match
    else:
        match = grade(golden_id, pre) == grade(golden_id, post)
    return {
        "task_id": golden_id,
        "match": match,
        "byte_match": byte_match,
        "pre_export": pre,
        "post_export": post,
    }

def main(export_path: str, goldens_path: str, pre_export_path: str, *, lossless: bool):
    goldens = load_goldens(goldens_path, n=5)
    pre_outputs = load_pre_export_outputs(pre_export_path)
    model = load_exported_model(export_path)

    reports = []
    for row in goldens:
        post = generate(model, row["prompt"], **SMOKE_TEST_GENERATION_KWARGS)
        pre = pre_outputs[row["task_id"]]
        reports.append(diff_report(row["task_id"], pre, post, lossless=lossless))

    failures = [r for r in reports if not r["match"]]
    print(json.dumps({"total": len(reports), "failures": len(failures),
                       "mode": "byte-match" if lossless else "graded-verdict"}, indent=2))
    for r in failures:
        print(f"MISMATCH {r['task_id']} (byte_match={r['byte_match']}):")
        print(f"  pre : {r['pre_export'][:200]}")
        print(f"  post: {r['post_export'][:200]}")

    # non-zero exit on any mismatch — this script
    # gates the export, it does not just report on it
    sys.exit(1 if failures else 0)

if __name__ == "__main__":
    # lossless=True only for an unquantized fp16/bf16 merge;
    # every quantized format (Q4_K_M, AWQ, FP8, ...) is lossless=False
    main(*sys.argv[1:4], lossless=False)

A failing run's mismatches are the diagnostic signal — read the pre/post pair before re-exporting: garbled or run-on text points to a template mismatch, fluent-but-wrong-answer text points to a quantized lm_head, per the failure signatures in SKILL.md's Smoke Test section. For a lossy export, byte_match=False on a passing (match=True) row is expected and not itself a failure signature — only a grader verdict flip is.

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs Python

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Attribution and licence

Created by
Seth Hobson
Publisher
Seth Hobson (Community)
Source
wshobson/agents · plugins/llm-finetuning/skills/quantized-export · commit 4bde316
Licence
MIT License (redistribution allowed)
  • LICENSE (added by AutoGineer from LICENSE)
  • ATTRIBUTION.md (written by AutoGineer)
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