diff --git a/.agents/workflows/evaluation-development.md b/.agents/workflows/evaluation-development.md
index 8339e7078..4b04fe1ff 100644
--- a/.agents/workflows/evaluation-development.md
+++ b/.agents/workflows/evaluation-development.md
@@ -64,8 +64,9 @@ via `@register("<group>.<name>")` and are auto-discovered when
   (`fastvideo/eval/metrics/common/`, `audio/`, `vlm/`).
 - **Metrics that wrap upstream research code**: follow the vbench
   pattern in `fastvideo/eval/metrics/vbench/`:
-  - upstream is a git submodule under `<metric>/external/upstream/`,
-    pinned to a SHA in repo-root `.gitmodules`;
+  - upstream is a git submodule under
+    `fastvideo/third_party/eval/<bench>/`, pinned to a SHA in repo-root
+    `.gitmodules`;
   - the metric package's `__init__.py` does the `sys.path` insert AND
     installs runtime compat shims (attribute-level monkey-patches) for
     any modern-dep drift. **Do not** modify upstream files on disk and
diff --git a/fastvideo/eval/README.md b/fastvideo/eval/README.md
index 2ed9cbddd..53eb9f976 100644
--- a/fastvideo/eval/README.md
+++ b/fastvideo/eval/README.md
@@ -133,11 +133,14 @@ module).
 
 Pattern: see `fastvideo/eval/metrics/vbench/`. The contract is:
 
-1. `<bench>/external/upstream/` is a git submodule pinned to a SHA
-   (registered in repo-root `.gitmodules`).
-2. `<bench>/__init__.py` inserts that path on `sys.path` and installs
-   any compat shims (attribute-level monkey-patches) needed for modern
-   torch/transformers/numpy. **Do not modify upstream files on disk.**
+1. The upstream code lives as a git submodule under
+   `fastvideo/third_party/eval/<bench>/`, pinned to a SHA (registered
+   in repo-root `.gitmodules`).
+2. The metric package's `__init__.py`
+   (`fastvideo/eval/metrics/<bench>/__init__.py`) inserts that submodule
+   path on `sys.path` and installs any compat shims (attribute-level
+   monkey-patches) needed for modern torch/transformers/numpy.
+   **Do not modify upstream files on disk.**
 3. Per-sub-metric `metric.py` files use `@register("<bench>.<name>")`.
 
 There is no per-benchmark setup script. Patches live as Python in
diff --git a/fastvideo/eval/metrics/__init__.py b/fastvideo/eval/metrics/__init__.py
index 04cc64823..b7c8d0b7f 100644
--- a/fastvideo/eval/metrics/__init__.py
+++ b/fastvideo/eval/metrics/__init__.py
@@ -1,9 +1,9 @@
 """Auto-discover and register all built-in metrics (recursive).
 
-Manually walks the metrics package tree and imports any leaf-package's
-`metric` module so @register decorators fire. Skips any path component
-starting with `_` (e.g. _vendor_*, _third_party) to avoid pulling in
-vendored model code that may have side-effecting imports.
+Walks the metrics package tree and imports any leaf-package's
+``metric`` module so ``@register`` decorators fire. Path components
+starting with ``_`` are skipped (used for shared helpers like
+``optical_flow/_shared.py`` and `vbench/_grit_helper.py`).
 """
 
 import importlib
diff --git a/fastvideo/eval/metrics/audio/audiobox_aesthetics/__init__.py b/fastvideo/eval/metrics/audio/audiobox_aesthetics/__init__.py
index ec0d38874..e69de29bb 100644
--- a/fastvideo/eval/metrics/audio/audiobox_aesthetics/__init__.py
+++ b/fastvideo/eval/metrics/audio/audiobox_aesthetics/__init__.py
@@ -1 +0,0 @@
-from .metric import VBAudioBoxAestheticsMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/audio/frechet_distance/__init__.py b/fastvideo/eval/metrics/audio/frechet_distance/__init__.py
index 4e4e469e3..e69de29bb 100644
--- a/fastvideo/eval/metrics/audio/frechet_distance/__init__.py
+++ b/fastvideo/eval/metrics/audio/frechet_distance/__init__.py
@@ -1 +0,0 @@
-from .metric import VBFrechetDistanceAudioMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/audio/kl_divergence/__init__.py b/fastvideo/eval/metrics/audio/kl_divergence/__init__.py
index 9452911b9..e69de29bb 100644
--- a/fastvideo/eval/metrics/audio/kl_divergence/__init__.py
+++ b/fastvideo/eval/metrics/audio/kl_divergence/__init__.py
@@ -1 +0,0 @@
-from .metric import VBKLDivergenceAudioMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/audio/wer/__init__.py b/fastvideo/eval/metrics/audio/wer/__init__.py
index 2fe6fbfe9..e69de29bb 100644
--- a/fastvideo/eval/metrics/audio/wer/__init__.py
+++ b/fastvideo/eval/metrics/audio/wer/__init__.py
@@ -1 +0,0 @@
-from .metric import VBWERMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/common/lpips/__init__.py b/fastvideo/eval/metrics/common/lpips/__init__.py
index da4b9afe2..e69de29bb 100644
--- a/fastvideo/eval/metrics/common/lpips/__init__.py
+++ b/fastvideo/eval/metrics/common/lpips/__init__.py
@@ -1 +0,0 @@
-from .metric import LPIPSMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/common/psnr/__init__.py b/fastvideo/eval/metrics/common/psnr/__init__.py
index 4dbf1dd88..e69de29bb 100644
--- a/fastvideo/eval/metrics/common/psnr/__init__.py
+++ b/fastvideo/eval/metrics/common/psnr/__init__.py
@@ -1 +0,0 @@
-from .metric import PSNRMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/common/ssim/__init__.py b/fastvideo/eval/metrics/common/ssim/__init__.py
index 4bd26ec80..e69de29bb 100644
--- a/fastvideo/eval/metrics/common/ssim/__init__.py
+++ b/fastvideo/eval/metrics/common/ssim/__init__.py
@@ -1 +0,0 @@
-from .metric import SSIMMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/physics_iq/mse/__init__.py b/fastvideo/eval/metrics/physics_iq/mse/__init__.py
index b3a5ac6d9..e69de29bb 100644
--- a/fastvideo/eval/metrics/physics_iq/mse/__init__.py
+++ b/fastvideo/eval/metrics/physics_iq/mse/__init__.py
@@ -1 +0,0 @@
-from fastvideo.eval.metrics.physics_iq.mse.metric import PhysicsIQMSEMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/physics_iq/spatial_iou/__init__.py b/fastvideo/eval/metrics/physics_iq/spatial_iou/__init__.py
index cc9200247..e69de29bb 100644
--- a/fastvideo/eval/metrics/physics_iq/spatial_iou/__init__.py
+++ b/fastvideo/eval/metrics/physics_iq/spatial_iou/__init__.py
@@ -1 +0,0 @@
-from fastvideo.eval.metrics.physics_iq.spatial_iou.metric import SpatialIoUMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/physics_iq/spatiotemporal_iou/__init__.py b/fastvideo/eval/metrics/physics_iq/spatiotemporal_iou/__init__.py
index 49e8992db..e69de29bb 100644
--- a/fastvideo/eval/metrics/physics_iq/spatiotemporal_iou/__init__.py
+++ b/fastvideo/eval/metrics/physics_iq/spatiotemporal_iou/__init__.py
@@ -1 +0,0 @@
-from fastvideo.eval.metrics.physics_iq.spatiotemporal_iou.metric import SpatiotemporalIoUMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/physics_iq/weighted_spatial_iou/__init__.py b/fastvideo/eval/metrics/physics_iq/weighted_spatial_iou/__init__.py
index 41d7abd81..e69de29bb 100644
--- a/fastvideo/eval/metrics/physics_iq/weighted_spatial_iou/__init__.py
+++ b/fastvideo/eval/metrics/physics_iq/weighted_spatial_iou/__init__.py
@@ -1 +0,0 @@
-from fastvideo.eval.metrics.physics_iq.weighted_spatial_iou.metric import WeightedSpatialIoUMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/appearance_style/__init__.py b/fastvideo/eval/metrics/vbench/appearance_style/__init__.py
index 847f3aac9..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/appearance_style/__init__.py
+++ b/fastvideo/eval/metrics/vbench/appearance_style/__init__.py
@@ -1 +0,0 @@
-from .metric import AppearanceStyleMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/background_consistency/__init__.py b/fastvideo/eval/metrics/vbench/background_consistency/__init__.py
index bff4aaf7d..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/background_consistency/__init__.py
+++ b/fastvideo/eval/metrics/vbench/background_consistency/__init__.py
@@ -1 +0,0 @@
-from .metric import BackgroundConsistencyMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/color/__init__.py b/fastvideo/eval/metrics/vbench/color/__init__.py
index b1d1688bf..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/color/__init__.py
+++ b/fastvideo/eval/metrics/vbench/color/__init__.py
@@ -1 +0,0 @@
-from .metric import ColorMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/dynamic_degree/__init__.py b/fastvideo/eval/metrics/vbench/dynamic_degree/__init__.py
index 4a64820ff..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/dynamic_degree/__init__.py
+++ b/fastvideo/eval/metrics/vbench/dynamic_degree/__init__.py
@@ -1 +0,0 @@
-from .metric import DynamicDegreeMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/human_action/__init__.py b/fastvideo/eval/metrics/vbench/human_action/__init__.py
index e292f250e..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/human_action/__init__.py
+++ b/fastvideo/eval/metrics/vbench/human_action/__init__.py
@@ -1 +0,0 @@
-from .metric import HumanActionMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/imaging_quality/__init__.py b/fastvideo/eval/metrics/vbench/imaging_quality/__init__.py
index 73295fd42..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/imaging_quality/__init__.py
+++ b/fastvideo/eval/metrics/vbench/imaging_quality/__init__.py
@@ -1 +0,0 @@
-from .metric import ImagingQualityMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/motion_smoothness/__init__.py b/fastvideo/eval/metrics/vbench/motion_smoothness/__init__.py
index 6b77b99b8..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/motion_smoothness/__init__.py
+++ b/fastvideo/eval/metrics/vbench/motion_smoothness/__init__.py
@@ -1 +0,0 @@
-from .metric import MotionSmoothnessMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/multiple_objects/__init__.py b/fastvideo/eval/metrics/vbench/multiple_objects/__init__.py
index 7c5ae8a25..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/multiple_objects/__init__.py
+++ b/fastvideo/eval/metrics/vbench/multiple_objects/__init__.py
@@ -1 +0,0 @@
-from .metric import MultipleObjectsMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/object_class/__init__.py b/fastvideo/eval/metrics/vbench/object_class/__init__.py
index f6e5859f8..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/object_class/__init__.py
+++ b/fastvideo/eval/metrics/vbench/object_class/__init__.py
@@ -1 +0,0 @@
-from .metric import ObjectClassMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/overall_consistency/__init__.py b/fastvideo/eval/metrics/vbench/overall_consistency/__init__.py
index 8cc217229..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/overall_consistency/__init__.py
+++ b/fastvideo/eval/metrics/vbench/overall_consistency/__init__.py
@@ -1 +0,0 @@
-from .metric import OverallConsistencyMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/scene/__init__.py b/fastvideo/eval/metrics/vbench/scene/__init__.py
index e90a95377..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/scene/__init__.py
+++ b/fastvideo/eval/metrics/vbench/scene/__init__.py
@@ -1 +0,0 @@
-from .metric import SceneMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/spatial_relationship/__init__.py b/fastvideo/eval/metrics/vbench/spatial_relationship/__init__.py
index 284a6a7de..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/spatial_relationship/__init__.py
+++ b/fastvideo/eval/metrics/vbench/spatial_relationship/__init__.py
@@ -1 +0,0 @@
-from .metric import SpatialRelationshipMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/subject_consistency/__init__.py b/fastvideo/eval/metrics/vbench/subject_consistency/__init__.py
index 2379ad5c0..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/subject_consistency/__init__.py
+++ b/fastvideo/eval/metrics/vbench/subject_consistency/__init__.py
@@ -1 +0,0 @@
-from .metric import SubjectConsistencyMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/temporal_flickering/__init__.py b/fastvideo/eval/metrics/vbench/temporal_flickering/__init__.py
index 12d6ca34e..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/temporal_flickering/__init__.py
+++ b/fastvideo/eval/metrics/vbench/temporal_flickering/__init__.py
@@ -1 +0,0 @@
-from .metric import TemporalFlickeringMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/vbench/temporal_style/__init__.py b/fastvideo/eval/metrics/vbench/temporal_style/__init__.py
index 321a180d0..e69de29bb 100644
--- a/fastvideo/eval/metrics/vbench/temporal_style/__init__.py
+++ b/fastvideo/eval/metrics/vbench/temporal_style/__init__.py
@@ -1 +0,0 @@
-from .metric import TemporalStyleMetric  # noqa: F401
diff --git a/fastvideo/eval/metrics/videoscore2/__init__.py b/fastvideo/eval/metrics/videoscore2/__init__.py
index b15c68a25..e69de29bb 100644
--- a/fastvideo/eval/metrics/videoscore2/__init__.py
+++ b/fastvideo/eval/metrics/videoscore2/__init__.py
@@ -1 +0,0 @@
-from .metric import VideoScore2Metric  # noqa: F401
diff --git a/pyproject.toml b/pyproject.toml
index 175881728..0a40befe2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -134,11 +134,9 @@ test = [
 eval = [
     "decord",
     "openai-clip",
-    "open_clip_torch",
     "pyiqa",
     "ptlflow",
     "lpips",
-    "torchmetrics",
     "easydict",
     "qwen-vl-utils",
 ]