diff --git a/tests/diffusion/diffusion_kv/test_layout.py b/tests/diffusion/diffusion_kv/test_layout.py
index 2f410f74c..713849e95 100644
--- a/tests/diffusion/diffusion_kv/test_layout.py
+++ b/tests/diffusion/diffusion_kv/test_layout.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 """Physical KV cache layout selection and propagation for the Diffusion cache."""
 
 from __future__ import annotations
diff --git a/tests/diffusion/diffusion_kv/test_manager.py b/tests/diffusion/diffusion_kv/test_manager.py
index 8abc296f1..ed39f6523 100644
--- a/tests/diffusion/diffusion_kv/test_manager.py
+++ b/tests/diffusion/diffusion_kv/test_manager.py
@@ -1,14 +1,14 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 
 import pytest
 import torch
 import vllm.v1.core.single_type_kv_cache_manager as native_kv_managers
 from vllm.v1.kv_cache_interface import FullAttentionSpec, KVCacheConfig, KVCacheGroupSpec
 
+from tests.helpers.kv_layout import build_kv_cache_tensor
 from vllm_omni.diffusion.diffusion_kv.manager import DiffusionKVAdmissionError, DiffusionKVCacheManager
 from vllm_omni.diffusion.diffusion_kv.request import DiffusionKVContext, DiffusionKVRequest
-from tests.helpers.kv_layout import build_kv_cache_tensor
 
 pytestmark = [pytest.mark.core_model, pytest.mark.cpu, pytest.mark.diffusion]
 
diff --git a/tests/diffusion/diffusion_kv/test_paged_attention_adapter.py b/tests/diffusion/diffusion_kv/test_paged_attention_adapter.py
index a13e09051..535c1b411 100644
--- a/tests/diffusion/diffusion_kv/test_paged_attention_adapter.py
+++ b/tests/diffusion/diffusion_kv/test_paged_attention_adapter.py
@@ -15,10 +15,10 @@ import torch
 from torch import nn
 from vllm.v1.kv_cache_interface import FullAttentionSpec
 
+from tests.helpers.kv_layout import layout_for_backend
 from vllm_omni.diffusion.attention.backends.flash_attn import FlashAttentionImpl
 from vllm_omni.diffusion.attention.layer import Attention
 from vllm_omni.diffusion.diffusion_kv import paged_attention_adapter as adapter_module
-from tests.helpers.kv_layout import layout_for_backend
 from vllm_omni.diffusion.diffusion_kv.paged_attention_adapter import (
     DiffusionPagedAttentionAdapter,
     DiffusionPagedAttentionMetadata,
diff --git a/tests/diffusion/diffusion_kv/test_paged_attention_adapter_gpu.py b/tests/diffusion/diffusion_kv/test_paged_attention_adapter_gpu.py
index 192e60bea..d890dcc7b 100644
--- a/tests/diffusion/diffusion_kv/test_paged_attention_adapter_gpu.py
+++ b/tests/diffusion/diffusion_kv/test_paged_attention_adapter_gpu.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 
 from __future__ import annotations
 
@@ -14,6 +14,7 @@ from vllm.v1.kv_cache_interface import FullAttentionSpec, KVCacheConfig, KVCache
 from vllm.v1.worker.gpu.attn_utils import init_attn_backend, init_kv_cache
 from vllm.v1.worker.gpu.block_table import BlockTables
 
+from tests.helpers.kv_layout import build_kv_cache_tensor
 from vllm_omni.diffusion.attention.backends.abstract import AttentionMetadata
 from vllm_omni.diffusion.attention.backends.flash_attn import FlashAttentionImpl
 from vllm_omni.diffusion.diffusion_kv.layout import resolve_diffusion_kv_cache_layout
@@ -24,7 +25,6 @@ from vllm_omni.diffusion.diffusion_kv.paged_attention_adapter import (
     DiffusionPagedAttentionRowBinding,
 )
 from vllm_omni.diffusion.vllm_config import _DiffusionVllmModelConfig
-from tests.helpers.kv_layout import build_kv_cache_tensor
 
 pytestmark = [pytest.mark.core_model, pytest.mark.diffusion, pytest.mark.gpu]
 
@@ -90,9 +90,7 @@ def test_adapter_executes_native_paged_attention_on_non_contiguous_blocks() -> N
     canonical_spec = native_layer.spec
     kv_cache_config = KVCacheConfig(
         num_blocks=4,
-        kv_cache_tensors=[
-            build_kv_cache_tensor(canonical_spec, 4, [_LAYER_NAME])
-        ],
+        kv_cache_tensors=[build_kv_cache_tensor(canonical_spec, 4, [_LAYER_NAME])],
         kv_cache_groups=[
             KVCacheGroupSpec(
                 layer_names=[_LAYER_NAME],
diff --git a/tests/diffusion/diffusion_kv/test_request.py b/tests/diffusion/diffusion_kv/test_request.py
index 4ca6703d8..ac9185e09 100644
--- a/tests/diffusion/diffusion_kv/test_request.py
+++ b/tests/diffusion/diffusion_kv/test_request.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 
 import pytest
 import torch
@@ -13,8 +13,8 @@ from vllm.v1.kv_cache_interface import (
 )
 from vllm.v1.request import RequestStatus
 
-from vllm_omni.diffusion.diffusion_kv.request import DiffusionKVContext, DiffusionKVRequest
 from tests.helpers.kv_layout import build_kv_cache_tensor
+from vllm_omni.diffusion.diffusion_kv.request import DiffusionKVContext, DiffusionKVRequest
 
 pytestmark = [pytest.mark.core_model, pytest.mark.cpu, pytest.mark.diffusion]
 
diff --git a/tests/diffusion/diffusion_kv/test_spec_discovery.py b/tests/diffusion/diffusion_kv/test_spec_discovery.py
index d07c41355..1ccef7a9f 100644
--- a/tests/diffusion/diffusion_kv/test_spec_discovery.py
+++ b/tests/diffusion/diffusion_kv/test_spec_discovery.py
@@ -11,11 +11,11 @@ from torch import nn
 from vllm.v1.kv_cache_interface import FullAttentionSpec, KVCacheConfig, KVCacheGroupSpec
 
 import vllm_omni.diffusion.worker.diffusion_worker as diffusion_worker_module
+from tests.helpers.kv_layout import build_kv_cache_tensor, layout_for_backend
 from vllm_omni.diffusion.attention.layer import Attention
 from vllm_omni.diffusion.diffusion_kv.config import DiffusionKVCacheMode
 from vllm_omni.diffusion.worker.diffusion_model_runner import DiffusionModelRunner
 from vllm_omni.diffusion.worker.diffusion_worker import DiffusionWorker
-from tests.helpers.kv_layout import build_kv_cache_tensor, layout_for_backend
 
 pytestmark = [pytest.mark.core_model, pytest.mark.cpu, pytest.mark.diffusion]
 
diff --git a/tests/diffusion/layers/test_adalayernorm.py b/tests/diffusion/layers/test_adalayernorm.py
index 51fc52f35..94cadf5ac 100644
--- a/tests/diffusion/layers/test_adalayernorm.py
+++ b/tests/diffusion/layers/test_adalayernorm.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 """Unit tests for shared AdaLayerNorm layers used by FLUX and other models."""
 
 import os
diff --git a/tests/diffusion/models/dreamzero/test_qkv_fusion.py b/tests/diffusion/models/dreamzero/test_qkv_fusion.py
index c7b2f032f..d67a01e48 100644
--- a/tests/diffusion/models/dreamzero/test_qkv_fusion.py
+++ b/tests/diffusion/models/dreamzero/test_qkv_fusion.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 
 """Equivalence test for DreamZero self-attn QKV fusion.
 
diff --git a/tests/diffusion/models/glm_image/test_glm_image_quantization.py b/tests/diffusion/models/glm_image/test_glm_image_quantization.py
index c08bfb894..1a6170ca2 100644
--- a/tests/diffusion/models/glm_image/test_glm_image_quantization.py
+++ b/tests/diffusion/models/glm_image/test_glm_image_quantization.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 """Unit tests for GLM-Image quantization support (W4A16/AutoRound).
 
 These tests verify that the GLM-Image DiT transformer correctly accepts and uses
diff --git a/tests/diffusion/models/mistral_encoder/test_mistral_encoder_tp.py b/tests/diffusion/models/mistral_encoder/test_mistral_encoder_tp.py
index 17fc1540e..62bcf9ce8 100644
--- a/tests/diffusion/models/mistral_encoder/test_mistral_encoder_tp.py
+++ b/tests/diffusion/models/mistral_encoder/test_mistral_encoder_tp.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 from types import SimpleNamespace
 
 import pytest
diff --git a/tests/diffusion/models/sana_video/test_transformer_sana_video.py b/tests/diffusion/models/sana_video/test_transformer_sana_video.py
index 3e1e40c2a..9e6404b21 100644
--- a/tests/diffusion/models/sana_video/test_transformer_sana_video.py
+++ b/tests/diffusion/models/sana_video/test_transformer_sana_video.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 
 import os
 
diff --git a/tests/diffusion/models/sana_video/test_transformer_sana_video_tp.py b/tests/diffusion/models/sana_video/test_transformer_sana_video_tp.py
index 7105f5b4c..a44c90146 100644
--- a/tests/diffusion/models/sana_video/test_transformer_sana_video_tp.py
+++ b/tests/diffusion/models/sana_video/test_transformer_sana_video_tp.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 
 """TP unit tests for SANA-Video: distributed RMSNorm, sharded attention and
 sharded GLUMB temporal conv.
diff --git a/tests/diffusion/models/t5_encoder/test_t5_encoder_tp.py b/tests/diffusion/models/t5_encoder/test_t5_encoder_tp.py
index 6eb469fac..cca73fb08 100644
--- a/tests/diffusion/models/t5_encoder/test_t5_encoder_tp.py
+++ b/tests/diffusion/models/t5_encoder/test_t5_encoder_tp.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 import pytest
 import torch
 from transformers import T5Config
diff --git a/tests/diffusion/test_diffusion_scheduler.py b/tests/diffusion/test_diffusion_scheduler.py
index 6bc0bdaba..20a2f0384 100644
--- a/tests/diffusion/test_diffusion_scheduler.py
+++ b/tests/diffusion/test_diffusion_scheduler.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 
 import asyncio
 import queue
@@ -12,6 +12,7 @@ import vllm.v1.core.single_type_kv_cache_manager as native_kv_managers
 from pytest_mock import MockerFixture
 from vllm.v1.kv_cache_interface import FullAttentionSpec, KVCacheConfig, KVCacheGroupSpec
 
+from tests.helpers.kv_layout import build_kv_cache_tensor
 from vllm_omni.diffusion.data import DiffusionOutput, DiffusionRequestAbortedError
 from vllm_omni.diffusion.diffusion_engine import DiffusionEngine, DiffusionExecutionMode
 from vllm_omni.diffusion.diffusion_kv.config import DiffusionKVCacheMode
@@ -27,7 +28,6 @@ from vllm_omni.diffusion.sched import (
 from vllm_omni.diffusion.sched.interface import CachedRequestData, NewRequestData
 from vllm_omni.diffusion.worker.utils import BatchRunnerOutput, RunnerOutput
 from vllm_omni.inputs.data import OmniDiffusionSamplingParams
-from tests.helpers.kv_layout import build_kv_cache_tensor
 
 pytestmark = [pytest.mark.core_model, pytest.mark.cpu, pytest.mark.diffusion]
 
diff --git a/tests/helpers/kv_layout.py b/tests/helpers/kv_layout.py
index 0306cee42..8351de8da 100644
--- a/tests/helpers/kv_layout.py
+++ b/tests/helpers/kv_layout.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 """Shared access to the production ``KVCacheTensor`` layout derivation.
 
 Tests deliberately go through the same code production uses
diff --git a/vllm_omni/diffusion/diffusion_kv/initialization.py b/vllm_omni/diffusion/diffusion_kv/initialization.py
index ffb0c2176..d1a79d934 100644
--- a/vllm_omni/diffusion/diffusion_kv/initialization.py
+++ b/vllm_omni/diffusion/diffusion_kv/initialization.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 
 from __future__ import annotations
 
diff --git a/vllm_omni/diffusion/diffusion_kv/layout.py b/vllm_omni/diffusion/diffusion_kv/layout.py
index 1ba0cd326..960df395d 100644
--- a/vllm_omni/diffusion/diffusion_kv/layout.py
+++ b/vllm_omni/diffusion/diffusion_kv/layout.py
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 """Physical KV cache layout selection for the native Diffusion paged cache.
 
 vLLM 0.29 removed ``AttentionSpec.indexes_kv_by_block_stride`` and replaced it
@@ -44,8 +44,8 @@ def resolve_diffusion_kv_cache_layout(
 
     A layout already present on the config wins, mirroring upstream's
     ``resolve_kv_cache_layout``; it is validated against the requirement rather
-    than silently overwritten, because an inconsistent layout mis-addresses K/V
-    instead of raising.
+    than silently overwritten, because an inconsistent layout reads K/V
+    from the wrong offsets instead of raising.
     """
 
     required_block_outermost = bool(indexes_kv_by_block_stride)
@@ -53,11 +53,7 @@ def resolve_diffusion_kv_cache_layout(
     if cache_config is None:
         # A config double with nowhere to record the choice; report what the
         # requirement implies without pretending it was pinned.
-        return (
-            BLOCK_STRIDE_DIFFUSION_KV_CACHE_LAYOUT
-            if required_block_outermost
-            else DEFAULT_DIFFUSION_KV_CACHE_LAYOUT
-        )
+        return BLOCK_STRIDE_DIFFUSION_KV_CACHE_LAYOUT if required_block_outermost else DEFAULT_DIFFUSION_KV_CACHE_LAYOUT
 
     current = getattr(cache_config, "kv_cache_layout", None)
     if current is not None:
@@ -72,11 +68,7 @@ def resolve_diffusion_kv_cache_layout(
             )
         return layout
 
-    layout = (
-        BLOCK_STRIDE_DIFFUSION_KV_CACHE_LAYOUT
-        if required_block_outermost
-        else DEFAULT_DIFFUSION_KV_CACHE_LAYOUT
-    )
+    layout = BLOCK_STRIDE_DIFFUSION_KV_CACHE_LAYOUT if required_block_outermost else DEFAULT_DIFFUSION_KV_CACHE_LAYOUT
     cache_config.kv_cache_layout = layout.name
     return layout
 
@@ -107,8 +99,7 @@ def adopt_kv_cache_layout(vllm_config: VllmConfig, kv_cache_config) -> KVCacheLa
         cache_config.kv_cache_layout = name
     elif current != name:
         raise ValueError(
-            f"Worker KV cache layout {current!r} disagrees with the layout "
-            f"resolved by the control plane ({name!r})."
+            f"Worker KV cache layout {current!r} disagrees with the layout resolved by the control plane ({name!r})."
         )
     return KVCacheLayout[name]
 
@@ -132,7 +123,7 @@ def build_kv_cache_tensor(
 
     The strides come from upstream's own ``compute_layout_strides``, called the
     way ``vllm.v1.core.kv_cache_utils`` calls it, because hand-computed strides
-    mis-address K/V silently instead of raising.
+    read K/V from the wrong offsets silently instead of raising.
     """
 
     layout = layout or DEFAULT_DIFFUSION_KV_CACHE_LAYOUT
diff --git a/vllm_omni/diffusion/diffusion_kv/model_runner_backend.py b/vllm_omni/diffusion/diffusion_kv/model_runner_backend.py
index 79a0ded62..20f4db165 100644
--- a/vllm_omni/diffusion/diffusion_kv/model_runner_backend.py
+++ b/vllm_omni/diffusion/diffusion_kv/model_runner_backend.py
@@ -293,9 +293,7 @@ class DiffusionKVModelRunnerBackend:
                 # and dropped attn_groups/cache_dtype from the signature.
                 adopt_kv_cache_layout(self.vllm_config, kv_cache_config)
                 for layer_adapter in self._kv_cache_layer_adapters.values():
-                    assert_backend_layout_supported(
-                        self.vllm_config, getattr(layer_adapter, "attn_backend", None)
-                    )
+                    assert_backend_layout_supported(self.vllm_config, getattr(layer_adapter, "attn_backend", None))
                 init_kv_cache(
                     kv_caches,
                     self.vllm_config.compilation_config.static_forward_context,
diff --git a/vllm_omni/experimental/ar_diffusion/kv_cache/manager.py b/vllm_omni/experimental/ar_diffusion/kv_cache/manager.py
index 24f09210d..f4cb416f6 100644
--- a/vllm_omni/experimental/ar_diffusion/kv_cache/manager.py
+++ b/vllm_omni/experimental/ar_diffusion/kv_cache/manager.py
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 """Engine-level KV cache orchestration for AR-Diffusion models.
 
 This is the *body* of AR-Diffusion's KV management: it owns a vLLM ``KVCacheManager`` (a