[diffusion] feat: support serialized comfy convrot int8 dits (#35994)

docs/cookbook/diffusion/MiniMax/MiniMax-H3.mdx

@@ -281,11 +281,13 @@ contract and low resident weight memory, but that part is slower than a fully
 quantized FP8 GEMM. TP, Ulysses/Ring sequence parallelism, and
 component/layerwise offload are supported; FSDP inference is rejected.
 
-The `pruned_int8_convrot` files are detected but remain unsupported. They
+The `pruned_int8_convrot` files use the same override path and are detected
-require online regular-Hadamard ConvRot, dynamic INT8 activation quantization,
+automatically. Install `comfy-kitchen`, replace the FP8 filename above with
-and a matching W8A8 GEMM. SGLang fails before loading them instead of silently
+`minimax_h3_fl2va_pruned_int8_convrot.safetensors`, and still omit
-treating their stored INT8 values as ordinary weights. A native ConvRot kernel
+`--quantization`. SGLang loads their serialized INT8 weights and row scales into
-path should be added and benchmarked separately before these files are accepted.
+the fused ConvRot kernel without requantizing them. TP1/2/4 and sequence or
+layerwise offload are supported; TP8 violates the checkpoint's 256-element
+ConvRot group boundary, and FSDP is rejected.
 
 ### Advanced: precomputed AdaLN cache
 
@@ -907,7 +909,7 @@ sglang generate \
 `--attention-backend sol_attn` with
 `--attention-backend-config dense_backend=sage_attn,dense_steps=10` and
 `--component-attention-backends text_encoder=torch_sdpa,transformer=sol_attn`.
-See [Quantization](/docs/sglang-diffusion/quantization#kitchen-int8-online-quantization)
+See [Quantization](/docs/sglang-diffusion/quantization#kitchen-int8)
 and [Attention Backends](/docs/sglang-diffusion/attention_backends#sage-then-sol-hybrid).
 
 <Warning>

docs/docs/sglang-diffusion/quantization.mdx

@@ -50,10 +50,11 @@ directory directly as `--model-path`, but that is a compatibility path. If a
 repo contains multiple candidate checkpoints, pass
 `--transformer-weights-path` explicitly.
 
-MiniMax-H3 auto-detects the per-layer metadata in Comfy's
+MiniMax-H3 is a verified example for Comfy safetensors with per-layer metadata,
-`pruned_fp8_scaled` safetensors. Pass one selected FL2VA or Ref2VA file by local
+including `pruned_fp8_scaled` and serialized ConvRot INT8. Pass one selected
-path, `owner/repo/path/file.safetensors`, or direct Hugging Face file URL; do
+FL2VA or Ref2VA DiT file by local path, `owner/repo/path/file.safetensors`, or
-not combine it with `--quantization`. MiniMax-H3 GGUF usage is documented in
+direct Hugging Face file URL; do not combine it with `--quantization`. Its GGUF
+usage is documented in
 the [MiniMax-H3 cookbook](/cookbook/diffusion/MiniMax/MiniMax-H3#pre-quantized-gguf-transformer).
 
 ## Quantized Component Repositories
@@ -165,6 +166,14 @@ backend.
       <td>None</td>
       <td>CUDA; auto-detected; TP, sequence parallelism, and component/layerwise offload are supported, while FSDP is not. Checkpoint-marked <code>fc2</code> layers retain FP8 storage and use compute-dtype matmul.</td>
     </tr>
+    <tr>
+      <td><code>comfy-int8-convrot</code></td>
+      <td>One selected safetensors file with per-layer <code>int8_tensorwise</code> and ConvRot metadata</td>
+      <td><code>--transformer-weights-path</code></td>
+      <td>MiniMax-H3 native DiT; pruned FL2VA is E2E-verified and Ref2VA has the same validated tensor contract</td>
+      <td><code>comfy-kitchen</code></td>
+      <td>CUDA; auto-detected; uses the fused Kitchen INT8 kernel and validates weight/scale layout before model construction. TP requires every row-parallel input shard to preserve the checkpoint's ConvRot group boundary; the H3 256-group checkpoint supports TP1/2/4, not TP8. Offload is supported; FSDP is not.</td>
+    </tr>
     <tr>
       <td><code>qvg-kv</code></td>
       <td>Unquantized model with runtime causal KV-cache compression</td>
@@ -334,7 +343,14 @@ sglang generate \
 ```
 **Note:** Requires `aiter` package with MXFP4 kernel support
 
-### Kitchen INT8 Online Quantization
+### Kitchen INT8
+
+Serialized Comfy ConvRot INT8 DiTs are selected through
+`--transformer-weights-path` and auto-detected from their per-layer markers.
+They load INT8 weights and row scales directly; omit `--quantization`.
+
+For a BF16 checkpoint, `--quantization kitchen_int8` instead performs online
+quantization after loading:
 
 `kitchen_int8` quantizes DiT linear weights online from the stock BF16
 checkpoint. Forward uses the fused `comfy_kitchen.int8_linear` op (rotation,

python/sglang/multimodal_gen/runtime/layers/quantization/comfy_fp8.py

@@ -88,6 +88,8 @@ class ComfyFullPrecisionFp8LinearMethod(LinearMethodBase):
 class ComfyFp8Config(QuantizationConfig):
     """Dispatch each Linear according to its serialized ``comfy_quant`` marker."""
 
+    checkpoint_uses_native_qkv_layout = True
+
     def __init__(self, layer_markers: dict[str, dict[str, Any]]) -> None:
         super().__init__()
         self.layer_markers = layer_markers

python/sglang/multimodal_gen/runtime/layers/quantization/configs/base_config.py

@@ -67,6 +67,7 @@ class QuantizationConfig(ABC):
 
     # for quantization frameworks with a separate quantized model provided, e.g. Nunchaku
     quantized_model_path: str | None = None
+    checkpoint_uses_native_qkv_layout: bool = False
 
     def __init__(self):
         super().__init__()

python/sglang/multimodal_gen/runtime/layers/quantization/configs/kitchen_int8_config.py

@@ -1,11 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-"""Config for online INT8 ConvRot quantization via comfy_kitchen.
+"""Config for online or serialized INT8 ConvRot via comfy_kitchen."""
-
-A no-arg ``KitchenInt8Config()`` is the only supported form: weights load in
-their source dtype and are quantized in ``process_weights_after_loading``.
-
-Registered CLI name: ``kitchen_int8``.
-"""
 
 from __future__ import annotations
 
@@ -27,17 +21,14 @@ _SUPPORTED_GROUP_SIZES = (16, 64, 256)
 
 
 class KitchenInt8Config(QuantizationConfig):
-    """Config for online INT8 ConvRot quantization via comfy_kitchen.
+    """Dispatch online quantization or serialized Comfy ConvRot layers."""
-
-    A no-arg ``KitchenInt8Config()`` is the only supported form: weights load in
-    their source dtype and are quantized in ``process_weights_after_loading``.
-    """
 
     def __init__(
         self,
         group_size: int = 256,
         ignored_layers: list[str] | None = None,
         packed_modules_mapping: dict[str, list[str]] | None = None,
+        layer_markers: dict[str, dict[str, Any]] | None = None,
     ) -> None:
         super().__init__()
         if group_size not in _SUPPORTED_GROUP_SIZES:
@@ -48,6 +39,30 @@ class KitchenInt8Config(QuantizationConfig):
         self.group_size = group_size
         self.ignored_layers = ignored_layers or []
         self.packed_modules_mapping = packed_modules_mapping or {}
+        self.layer_markers = layer_markers
+        self.is_checkpoint_int8_serialized = layer_markers is not None
+        self.checkpoint_uses_native_qkv_layout = self.is_checkpoint_int8_serialized
+        self._serialized_group_sizes: dict[str, int] = {}
+        if layer_markers is not None:
+            for prefix, marker in layer_markers.items():
+                if marker.get("format") != "int8_tensorwise":
+                    raise ValueError(
+                        f"Unsupported Comfy INT8 format for {prefix!r}: "
+                        f"{marker.get('format')!r}"
+                    )
+                if marker.get("convrot") is not True:
+                    raise ValueError(
+                        f"Serialized kitchen_int8 layer {prefix!r} must set "
+                        "convrot=true"
+                    )
+                marker_group_size = marker.get("convrot_groupsize")
+                if marker_group_size not in _SUPPORTED_GROUP_SIZES:
+                    raise ValueError(
+                        f"Serialized kitchen_int8 layer {prefix!r} must declare "
+                        f"convrot_groupsize in {_SUPPORTED_GROUP_SIZES}, got "
+                        f"{marker_group_size!r}"
+                    )
+                self._serialized_group_sizes[prefix] = marker_group_size
         # Which layers actually got quantized is worth stating plainly in the
         # log: a silent fallback to BF16 looks exactly like a slow kernel.
         self.selected: list[str] = []
@@ -89,6 +104,22 @@ class KitchenInt8Config(QuantizationConfig):
 
         if not isinstance(layer, LinearBase):
             return None
+        if self.layer_markers is not None:
+            marker_group_size = self._serialized_group_sizes.get(prefix)
+            if marker_group_size is None:
+                return UnquantizedLinearMethod()
+            if layer.input_size % marker_group_size:
+                raise ValueError(
+                    f"Serialized kitchen_int8 layer {prefix!r} has input size "
+                    f"{layer.input_size}, which is not divisible by its "
+                    f"ConvRot group size {marker_group_size}"
+                )
+            self.selected.append(prefix)
+            return KitchenInt8LinearMethod(
+                self,
+                group_size=marker_group_size,
+                is_checkpoint_serialized=True,
+            )
         if is_layer_skipped(
             prefix, self.ignored_layers, fused_mapping=self.packed_modules_mapping
         ):
@@ -102,7 +133,11 @@ class KitchenInt8Config(QuantizationConfig):
             self.skipped.append(f"{prefix}(in={layer.input_size})")
             return UnquantizedLinearMethod()
         self.selected.append(prefix)
-        return KitchenInt8LinearMethod(self)
+        return KitchenInt8LinearMethod(
+            self,
+            group_size=self.group_size,
+            is_checkpoint_serialized=False,
+        )
 
     def note_quantized(self, saved_bytes: int) -> None:
         self._processed += 1

python/sglang/multimodal_gen/runtime/layers/quantization/kitchen_int8.py

@@ -8,10 +8,9 @@ The difference is that it is a single fused op -- it takes a BF16 activation and
 does the Hadamard rotation, dynamic per-row activation quantization, IMMA GEMM,
 dequantization and bias add without ever materializing the intermediates.
 
-Quantization is data-free (group-wise Hadamard rotation + per-output-channel
+The online path applies data-free group-wise Hadamard rotation and per-output
-absmax), so weights are quantized here after loading rather than read from a
+channel scaling after loading a stock BF16 checkpoint. Compatible serialized
-pre-quantized checkpoint. That keeps this usable with the stock BF16 checkpoint
+Comfy checkpoints instead load their INT8 weights and row scales directly.
-and avoids depending on any external file layout.
 """
 
 from __future__ import annotations
@@ -73,10 +72,18 @@ def _load_comfy_kitchen():
 
 
 class KitchenInt8LinearMethod(LinearMethodBase):
-    """Quantizes BF16 weights to INT8 after load and runs the fused kernel."""
+    """Loads or creates ConvRot INT8 weights and runs the fused kernel."""
 
-    def __init__(self, quant_config: KitchenInt8Config) -> None:
+    def __init__(
+        self,
+        quant_config: KitchenInt8Config,
+        *,
+        group_size: int,
+        is_checkpoint_serialized: bool,
+    ) -> None:
         self.quant_config = quant_config
+        self.group_size = group_size
+        self.is_checkpoint_serialized = is_checkpoint_serialized
         _load_comfy_kitchen()
 
     def create_weights(
@@ -92,36 +99,47 @@ class KitchenInt8LinearMethod(LinearMethodBase):
         # get_quant_method already screened the unsharded input size, so this
         # only fires under TP > 1, where a row-parallel layer splits the very
         # dimension the rotation groups over.
-        if input_size_per_partition % self.quant_config.group_size:
+        if input_size_per_partition % self.group_size:
             raise ValueError(
                 f"kitchen_int8 needs input_size_per_partition "
                 f"({input_size_per_partition}) divisible by group_size "
-                f"{self.quant_config.group_size}"
+                f"{self.group_size}"
             )
 
-        # Deliberately identical to UnquantizedLinearMethod: weights load as
+        # The online path initially matches UnquantizedLinearMethod so the
-        # BF16 through the model's existing loaders (H3 for instance installs a
+        # source weights load in BF16 before quantization. Serialized weights
-        # custom qkv loader that reorders the grouped checkpoint layout), and
+        # allocate their final INT8 storage immediately.
-        # only then get replaced by their quantized form.
         weight = Parameter(
             torch.empty(
                 sum(output_partition_sizes),
                 input_size_per_partition,
-                dtype=params_dtype,
+                dtype=(torch.int8 if self.is_checkpoint_serialized else params_dtype),
             ),
             requires_grad=False,
         )
         set_weight_attrs(weight, {"input_dim": 1, "output_dim": 0})
         layer.register_parameter("weight", weight)
         set_weight_attrs(weight, extra_weight_attrs)
+        if self.is_checkpoint_serialized:
+            weight_scale = Parameter(
+                torch.empty(
+                    sum(output_partition_sizes),
+                    1,
+                    dtype=torch.float32,
+                ),
+                requires_grad=False,
+            )
+            set_weight_attrs(weight_scale, {"output_dim": 0})
+            set_weight_attrs(weight_scale, extra_weight_attrs)
+            layer.register_parameter("weight_scale", weight_scale)
 
     def process_weights_after_loading(self, layer: torch.nn.Module) -> None:
-        from comfy_kitchen.tensor.int8 import TensorWiseINT8Layout
-
         weight = layer.weight.data
-        if weight.dtype == torch.int8:  # already processed
+        if self.is_checkpoint_serialized or weight.dtype == torch.int8:
             return
 
+        from comfy_kitchen.tensor.int8 import TensorWiseINT8Layout
+
         # Quantization runs on CUDA, but the model may still be staged on CPU
         # for offload. Round-trip one layer at a time rather than relying on
         # the loader's whole-model device move, which would not fit in VRAM.
@@ -131,7 +149,7 @@ class KitchenInt8LinearMethod(LinearMethodBase):
             is_weight=True,
             per_channel=True,
             convrot=True,
-            convrot_groupsize=self.quant_config.group_size,
+            convrot_groupsize=self.group_size,
             stochastic_rounding=0,
         )
         layer.weight = Parameter(qdata.to(home), requires_grad=False)
@@ -171,7 +189,7 @@ class KitchenInt8LinearMethod(LinearMethodBase):
                 bias,
                 out_code,
                 True,  # convrot
-                self.quant_config.group_size,
+                self.group_size,
             )
 
         n_rows, n_out = x.shape[0], layer.weight.shape[0]

python/sglang/multimodal_gen/runtime/loader/component_loaders/transformer_loader.py

@@ -280,10 +280,10 @@ class TransformerLoader(ComponentLoader):
             or cpu_offload_flag
         )
         use_fsdp = server_args.should_use_fsdp_for_component(component_name)
-        if quant_spec.is_comfy_fp8 and use_fsdp:
+        if quant_spec.uses_comfy_layer_markers and use_fsdp:
             raise ValueError(
-                "MiniMax-H3 Comfy FP8 does not support FSDP inference; use TP "
+                "Comfy quantized checkpoints do not support FSDP "
-                "and/or sequence parallelism instead"
+                "inference; use TP and/or sequence parallelism instead"
             )
 
         if quant_spec.gguf_file is not None:
@@ -308,7 +308,7 @@ class TransformerLoader(ComponentLoader):
             "quant_config": quant_spec.runtime_quant_config,
         }
         checkpoint_key_filter: Callable[[str], bool] | None = (
-            comfy_quant_key_filter if quant_spec.is_comfy_fp8 else None
+            comfy_quant_key_filter if quant_spec.uses_comfy_layer_markers else None
         )
         adaln_cache_path = component_server_args.minimax_h3_adaln_cache_path
         if adaln_cache_path is not None:
@@ -362,7 +362,10 @@ class TransformerLoader(ComponentLoader):
                 local_torch_device,
                 component_starts_on_cpu=component_starts_on_cpu,
                 runtime_quant_config=quant_spec.runtime_quant_config,
-                quantized_cpu_load_supported=quant_spec.gguf_file is not None,
+                quantized_cpu_load_supported=(
+                    quant_spec.gguf_file is not None
+                    or quant_spec.is_serialized_kitchen_int8
+                ),
             )
         )
         direct_gpu_weight_loading = bool(

python/sglang/multimodal_gen/runtime/loader/minimax_h3_weights.py

@@ -10,6 +10,9 @@ from sglang.multimodal_gen.runtime.layers.quantization.comfy_fp8 import ComfyFp8
 from sglang.multimodal_gen.runtime.layers.quantization.configs.base_config import (
     QuantizationConfig,
 )
+from sglang.multimodal_gen.runtime.layers.quantization.configs.kitchen_int8_config import (
+    KitchenInt8Config,
+)
 
 
 def comfy_quant_key_filter(name: str) -> bool:
@@ -23,6 +26,7 @@ def inspect_minimax_h3_safetensors(
     adaln_curve_shape = None
     layer_markers: dict[str, dict[str, Any]] = {}
     checkpoint_keys: set[str] = set()
+    checkpoint_meta: dict[str, tuple[str, tuple[int, ...]]] = {}
     fp8_weight_prefixes: set[str] = set()
 
     for path in safetensors_list:
@@ -44,11 +48,15 @@ def inspect_minimax_h3_safetensors(
                 adaln_curve_shape = shape
 
             for key in keys:
-                if (
+                if key.endswith((".weight", ".weight_scale")):
-                    key.endswith(".weight")
+                    tensor_slice = checkpoint.get_slice(key)
-                    and checkpoint.get_slice(key).get_dtype() == "F8_E4M3"
+                    dtype = tensor_slice.get_dtype()
-                ):
+                    checkpoint_meta[key] = (
-                    fp8_weight_prefixes.add(key.removesuffix(".weight"))
+                        dtype,
+                        tuple(tensor_slice.get_shape()),
+                    )
+                    if key.endswith(".weight") and dtype == "F8_E4M3":
+                        fp8_weight_prefixes.add(key.removesuffix(".weight"))
                 if not key.endswith(".comfy_quant"):
                     continue
                 try:
@@ -78,17 +86,39 @@ def inspect_minimax_h3_safetensors(
             )
 
     for prefix, marker in layer_markers.items():
-        if marker.get("format") != "float8_e4m3fn":
+        marker_format = marker.get("format")
-            continue
         required = {f"{prefix}.weight", f"{prefix}.weight_scale"}
-        if not marker.get("full_precision_matrix_mult", False):
+        if marker_format == "float8_e4m3fn" and not marker.get(
+            "full_precision_matrix_mult", False
+        ):
             required.add(f"{prefix}.input_scale")
+        if marker_format not in ("float8_e4m3fn", "int8_tensorwise"):
+            continue
         missing = required - checkpoint_keys
         if missing:
             raise ValueError(
-                f"MiniMax-H3 Comfy FP8 layer {prefix!r} is missing checkpoint "
+                f"MiniMax-H3 Comfy layer {prefix!r} is missing checkpoint "
                 f"tensors: {sorted(missing)}"
             )
+        if marker_format == "int8_tensorwise":
+            weight_dtype, weight_shape = checkpoint_meta[f"{prefix}.weight"]
+            scale_dtype, scale_shape = checkpoint_meta[f"{prefix}.weight_scale"]
+            if weight_dtype != "I8" or scale_dtype != "F32":
+                raise ValueError(
+                    f"MiniMax-H3 Comfy INT8 layer {prefix!r} needs I8 weights "
+                    f"and F32 scales, got {weight_dtype} and {scale_dtype}"
+                )
+            if len(weight_shape) != 2:
+                raise ValueError(
+                    f"MiniMax-H3 Comfy INT8 layer {prefix!r} needs a 2D weight, "
+                    f"got {weight_shape}"
+                )
+            expected_scale_shape = (weight_shape[0], 1)
+            if scale_shape != expected_scale_shape:
+                raise ValueError(
+                    f"MiniMax-H3 Comfy INT8 layer {prefix!r} needs scale shape "
+                    f"{expected_scale_shape}, got {scale_shape}"
+                )
 
     return adaln_curve_shape, layer_markers
 
@@ -100,13 +130,8 @@ def resolve_minimax_h3_checkpoint_quantization(
         return None
 
     formats = sorted({str(marker.get("format")) for marker in layer_markers.values()})
-    if "int8_tensorwise" in formats:
+    if formats == ["int8_tensorwise"]:
-        raise NotImplementedError(
+        return KitchenInt8Config(layer_markers=layer_markers)
-            "MiniMax-H3 pruned_int8_convrot is not supported yet. Its "
-            "int8_tensorwise weights require an online regular-Hadamard ConvRot "
-            "and dynamic INT8 activation quantization kernel; loading them as "
-            "ordinary INT8/BF16 weights would produce incorrect output."
-        )
     if formats == ["float8_e4m3fn"]:
         return ComfyFp8Config(layer_markers)
     raise NotImplementedError(

python/sglang/multimodal_gen/runtime/loader/transformer_load_utils.py

@@ -18,6 +18,9 @@ from diffusers.utils import SAFE_WEIGHTS_INDEX_NAME
 from torch import nn
 
 from sglang.multimodal_gen.runtime.layers.quantization import QuantizationConfig
+from sglang.multimodal_gen.runtime.layers.quantization.configs.kitchen_int8_config import (
+    KitchenInt8Config,
+)
 from sglang.multimodal_gen.runtime.layers.quantization.configs.nunchaku_config import (
     NunchakuConfig,
     _patch_nunchaku_scales,
@@ -164,6 +167,17 @@ class TransformerQuantLoadSpec:
     def is_comfy_fp8(self) -> bool:
         return _get_quant_config_name(self.quant_config) == "comfy_fp8"
 
+    @property
+    def is_serialized_kitchen_int8(self) -> bool:
+        return (
+            isinstance(self.quant_config, KitchenInt8Config)
+            and self.quant_config.is_checkpoint_int8_serialized
+        )
+
+    @property
+    def uses_comfy_layer_markers(self) -> bool:
+        return self.is_comfy_fp8 or self.is_serialized_kitchen_int8
+
 
 class _TransformerQuantAdapter:
     def prepare(self) -> None:
@@ -844,6 +858,9 @@ def _needs_device_weight_postprocess(
     quant_name = _get_quant_config_name(quant_config)
     if quant_name in ("modelopt_fp8", "comfy_fp8"):
         return True
+    if quant_name == "kitchen_int8":
+        assert isinstance(quant_config, KitchenInt8Config)
+        return not quant_config.is_checkpoint_int8_serialized
 
     serialized_flag_by_quant_name = {
         "fp8": "is_checkpoint_fp8_serialized",

python/sglang/multimodal_gen/runtime/models/dits/minimax_h3.py

@@ -612,10 +612,13 @@ class MiniMaxH3Attention(nn.Module):
             quant_config=quant_config,
             prefix=f"{prefix}.qkv_proj",
         )
-        # The reorder below translates the *safetensors* checkpoint layout. A
+        # Official safetensors interleave Q/K/V by head. Comfy and GGUF
-        # GGUF checkpoint already stores qkv as [q_all, k_all, v_all], and its
+        # checkpoints already store [q_all, k_all, v_all].
-        # packed parameter is `qweight`, so there is nothing to reorder.
+        checkpoint_qkv_is_native = quant_config is not None and (
-        if quant_config is None or quant_config.get_name() != "gguf":
+            quant_config.get_name() == "gguf"
+            or quant_config.checkpoint_uses_native_qkv_layout
+        )
+        if not checkpoint_qkv_is_native:
             self._install_qkv_weight_loader(arch)
         self.q_norm = _norm(arch.attention_head_dim, eps=arch.qk_norm_eps)
         self.k_norm = _norm(arch.attention_head_dim, eps=arch.qk_norm_eps)

python/sglang/multimodal_gen/test/unit/test_transformer_quant.py

@@ -47,12 +47,16 @@ sys.modules.setdefault("partial_json_parser.core.options", partial_json_parser_o
 
 from sglang.multimodal_gen.runtime.layers.linear import (
     LinearBase,
+    ReplicatedLinear,
     UnquantizedLinearMethod,
 )
 from sglang.multimodal_gen.runtime.layers.quantization.comfy_fp8 import (
     ComfyFp8Config,
     ComfyFullPrecisionFp8LinearMethod,
 )
+from sglang.multimodal_gen.runtime.layers.quantization.configs.kitchen_int8_config import (
+    KitchenInt8Config,
+)
 from sglang.multimodal_gen.runtime.layers.quantization.configs.nunchaku_config import (
     NunchakuConfig,
 )
@@ -246,11 +250,19 @@ class TestTransformerQuantHelpers(unittest.TestCase):
                 mock_download.reset_mock()
 
     def test_inspect_minimax_h3_safetensors_detects_curve_and_comfy_format(self):
-        marker = json.dumps({"format": "int8_tensorwise", "convrot": True}).encode()
+        marker = json.dumps(
+            {
+                "format": "int8_tensorwise",
+                "convrot": True,
+                "convrot_groupsize": 256,
+            }
+        ).encode()
         with tempfile.NamedTemporaryFile(suffix=".safetensors") as f:
             save_file(
                 {
                     "adaln_t_table": torch.zeros((1025, 8)),
+                    "blocks.0.mlp.fc1.weight": torch.ones((2, 256), dtype=torch.int8),
+                    "blocks.0.mlp.fc1.weight_scale": torch.ones((2, 1)),
                     "blocks.0.mlp.fc1.comfy_quant": torch.tensor(
                         list(marker), dtype=torch.uint8
                     ),
@@ -282,13 +294,60 @@ class TestTransformerQuantHelpers(unittest.TestCase):
 
         self.assertEqual(layer_markers["blocks.0.mlp.fc1"], {"format": "float8_e4m3fn"})
 
-    def test_minimax_h3_comfy_int8_fails_before_weight_loading(self):
+    def test_minimax_h3_comfy_int8_resolves_serialized_kitchen(self):
-        with self.assertRaisesRegex(NotImplementedError, "regular-Hadamard"):
+        config = resolve_minimax_h3_checkpoint_quantization(
+            {
+                "blocks.0.mlp.fc1": {
+                    "format": "int8_tensorwise",
+                    "convrot": True,
+                    "convrot_groupsize": 256,
+                }
+            }
+        )
+
+        self.assertIsInstance(config, KitchenInt8Config)
+        self.assertTrue(config.is_checkpoint_int8_serialized)
+        self.assertTrue(config.checkpoint_uses_native_qkv_layout)
+        self.assertFalse(KitchenInt8Config().checkpoint_uses_native_qkv_layout)
+        self.assertFalse(_needs_device_weight_postprocess(config))
+
+    @patch(
+        "sglang.multimodal_gen.runtime.layers.quantization.kitchen_int8."
+        "_load_comfy_kitchen"
+    )
+    def test_serialized_kitchen_constructs_int8_weight_and_row_scale(self, _load):
+        config = KitchenInt8Config(
+            layer_markers={
+                "proj": {
+                    "format": "int8_tensorwise",
+                    "convrot": True,
+                    "convrot_groupsize": 256,
+                }
+            }
+        )
+
+        layer = ReplicatedLinear(
+            256,
+            3,
+            bias=False,
+            params_dtype=torch.bfloat16,
+            quant_config=config,
+            prefix="proj",
+        )
+
+        self.assertEqual(layer.weight.dtype, torch.int8)
+        self.assertEqual(layer.weight.shape, (3, 256))
+        self.assertEqual(layer.weight_scale.dtype, torch.float32)
+        self.assertEqual(layer.weight_scale.shape, (3, 1))
+
+    def test_serialized_kitchen_rejects_non_convrot_marker(self):
+        with self.assertRaisesRegex(ValueError, "convrot=true"):
             resolve_minimax_h3_checkpoint_quantization(
                 {
                     "blocks.0.mlp.fc1": {
                         "format": "int8_tensorwise",
-                        "convrot": True,
+                        "convrot": False,
+                        "convrot_groupsize": 256,
                     }
                 }
             )
@@ -305,6 +364,7 @@ class TestTransformerQuantHelpers(unittest.TestCase):
         )
 
         self.assertIsInstance(config, ComfyFp8Config)
+        self.assertTrue(config.checkpoint_uses_native_qkv_layout)
         layer = LinearBase(input_size=1, output_size=1)
         self.assertIsInstance(
             config.get_quant_method(layer, "blocks.0.mlp.fc2"),