fix(downloads): close routing gaps and map CivitAI ModelType.UNet to the checkpoint branch

Cross-checked both baseModel lists against CivitAI's official
baseModelRecords (packages/civitai-shared src/basemodel.constants.ts):

- CHECKPOINT_BASE_MODELS gains SD 2.0/2.1 768, SD 2.1 Unclip, SDXL 0.9 /
  1.0 LCM / Turbo / Distilled, Playground v2 and Stable Cascade
  (unCLIP-style but CheckpointLoader-loaded).
- DIFFUSION_MODEL_BASE_MODELS gains SVD XT, LTXV 2.5, Flux 3 Video,
  Wan Image 2.7, Wan Video 2.7 / 3.0, HiDream-O1, Boogu and the Ming
  Image Design families. API-only (Kling/Sora/Veo/Imagen...), 3D and
  audio baseModels are intentionally skipped.
- Pony V7 exclusion now backed by live-API evidence (model 1901521 is
  AuraFlow-architecture shipping .gguf variants).

CivitAI has no model-level diffusion ModelType: DiT models are uploaded
as "Checkpoint" or "UNet", with only uploader-chosen file types to tell
them apart. model.type "unet" previously fell through type derivation
and failed with 'not supported for download'; it now goes through the
checkpoint branch in both the download manager and the download routing
endpoint, so the standard chain (file type -> baseModel lists -> unknown
default) applies.

py/routes/handlers/download_routing_handlers.py

@@ -55,6 +55,11 @@ class DownloadRoutingHandler:
                 status=400,
             )
 
+        # CivitAI ModelType.UNet downloads go through the checkpoint branch,
+        # same as in the download manager.
+        if model_type.lower() == "unet":
+            model_type = "checkpoint"
+
         if model_type.lower() in VALID_OTHER_CIVITAI_TYPES:
             from ...services.settings_manager import get_settings_manager
 

py/services/download_manager.py

@@ -1523,7 +1523,11 @@ class DownloadManager:
                 return {"success": False, "error": "Failed to fetch model metadata"}
 
             model_type_from_info = version_info.get("model", {}).get("type", "").lower()
-            if model_type_from_info == "checkpoint":
+            # CivitAI ModelType has no model-level diffusion variant: DiT
+            # models are uploaded as "Checkpoint" or "UNet". Both go through
+            # the checkpoint branch so the standard diffusion routing chain
+            # (file type -> baseModel lists -> unknown default) applies.
+            if model_type_from_info in ("checkpoint", "unet"):
                 model_type = "checkpoint"
             elif model_type_from_info in VALID_LORA_TYPES:
                 model_type = "lora"

py/utils/constants.py

@@ -352,12 +352,15 @@ DIFFUSION_MODEL_BASE_MODELS = frozenset(
         "PixArt E",
         # Video diffusion models
         "CogVideoX",
+        "Flux 3 Video",
         "Hunyuan Video",
         "LTXV",
         "LTXV2",
         "LTXV 2.3",
+        "LTXV 2.5",
         "Mochi",
         "SVD",
+        "SVD XT",
         "Wan Video",
         "Wan Video 1.3B t2v",
         "Wan Video 14B t2v",
@@ -368,12 +371,19 @@ DIFFUSION_MODEL_BASE_MODELS = frozenset(
         "Wan Video 2.2 T2V-A14B",
         "Wan Video 2.5 T2V",
         "Wan Video 2.5 I2V",
+        "Wan Video 2.7",
+        "Wan Video 3.0",
         # Other diffusion models
+        "Boogu",
         "Ernie",
         "Ernie Turbo",
+        "HiDream-O1",
+        "Ming Image Design 0.1",
+        "Ming Image Design Layer 0.1",
         "MiniMax H3",
         "Nucleus",
         "Qwen",
+        "Wan Image 2.7",
         "ZImageBase",
         "ZImageTurbo",
         # Krea 2 — loaded via UNETLoader in ComfyUI
@@ -385,9 +395,12 @@ DIFFUSION_MODEL_BASE_MODELS = frozenset(
 # CheckpointLoaderSimple in ComfyUI). New DiT families appear on CivitAI all
 # the time, so download routing inverts the fallback: anything NOT in this
 # closed set (and not a known diffusion model) is treated as a diffusion
-# model by default (see py/services/download_routing.py).
-# "Pony V7" is deliberately excluded: it is not an SDXL-derivative full
-# checkpoint, so it follows the unknown-base-model default (diffusion).
+# model by default (see py/services/download_routing.py). Cross-checked
+# against CivitAI's official baseModelRecords (packages/civitai-shared
+# src/basemodel.constants.ts), not only the download skip list.
+# "Pony V7" is deliberately excluded: verified via the live API (model
+# 1901521) to be AuraFlow-architecture shipping .gguf variants (UNETLoader),
+# so it follows the unknown-base-model default (diffusion).
 CHECKPOINT_BASE_MODELS = frozenset(
     [
         # Stable Diffusion 1.x
@@ -397,7 +410,10 @@ CHECKPOINT_BASE_MODELS = frozenset(
         "SD 1.5 Hyper",
         # Stable Diffusion 2.x
         "SD 2.0",
+        "SD 2.0 768",
         "SD 2.1",
+        "SD 2.1 768",
+        "SD 2.1 Unclip",
         # Stable Diffusion 3.x
         "SD 3",
         "SD 3.5",
@@ -405,12 +421,20 @@ CHECKPOINT_BASE_MODELS = frozenset(
         "SD 3.5 Large",
         "SD 3.5 Large Turbo",
         # SDXL and its full-checkpoint derivatives
+        "SDXL 0.9",
         "SDXL 1.0",
+        "SDXL 1.0 LCM",
         "SDXL Lightning",
         "SDXL Hyper",
+        "SDXL Turbo",
+        "SDXL Distilled",
         "Pony",
         "Illustrious",
         "NoobAI",
+        # Other full-checkpoint families
+        "Playground v2",
+        # Stable Cascade is unCLIP-style but loads via CheckpointLoader
+        "Stable Cascade",
     ]
 )
 

tests/routes/test_download_routing_handlers.py

@@ -109,6 +109,21 @@ async def test_unknown_base_model_honors_checkpoint_routing_setting():
     assert payload["root_kind"] == "checkpoint"
 
 
+@pytest.mark.asyncio
+async def test_unet_model_type_uses_checkpoint_branch():
+    """CivitAI ModelType.UNet has no branch of its own: it goes through the
+    checkpoint branch, where its UNet-typed files route to the unet roots."""
+    handler = DownloadRoutingHandler()
+    response = await handler.get_download_routing(
+        FakeRequest(
+            {"model_type": "unet", "base_model": "MiniMax H3", "file_types": ["UNet"]}
+        )
+    )
+    payload = json.loads(response.text)
+    assert payload["is_diffusion_model"] is True
+    assert payload["root_kind"] == "unet"
+
+
 @pytest.mark.asyncio
 async def test_lora_is_never_diffusion():
     handler = DownloadRoutingHandler()

tests/services/test_download_manager_basic.py

@@ -2200,6 +2200,54 @@ async def test_download_uses_raw_file_name_from_mini_endpoint(
     ]
 
 
+@pytest.mark.asyncio
+async def test_unet_model_type_download_lands_in_unet_roots(
+    monkeypatch, scanners, metadata_provider, tmp_path
+):
+    """CivitAI ModelType.UNet goes through the checkpoint branch: its
+    UNet-typed files route to the unet roots like any diffusion model."""
+    manager = DownloadManager()
+    unet_root = tmp_path / "unet"
+    get_settings_manager().settings["default_unet_root"] = str(unet_root)
+    metadata_provider.payload = {
+        "id": 42,
+        "model": {"type": "UNet", "tags": ["fantasy"]},
+        "baseModel": "MiniMax H3",
+        "creator": {"username": "Author"},
+        "files": [
+            {
+                "id": 1001,
+                "type": "UNet",
+                "primary": True,
+                "name": "minimax_h3.safetensors",
+                "downloadUrl": "https://example.invalid/file.safetensors",
+            }
+        ],
+    }
+
+    captured = {}
+
+    async def fake_execute_download(self, **kwargs):
+        captured["file_path"] = kwargs["metadata"].file_path
+        return {"success": True}
+
+    monkeypatch.setattr(
+        DownloadManager, "_execute_download", fake_execute_download, raising=False
+    )
+
+    result = await manager.download_from_civitai(
+        model_version_id=42,
+        save_dir=str(tmp_path),
+        use_default_paths=True,
+        progress_callback=None,
+        source=None,
+    )
+
+    assert result["success"] is True, result
+    assert captured["file_path"].startswith(str(unet_root))
+    assert captured["file_path"].endswith("minimax_h3.safetensors")
+
+
 @pytest.mark.asyncio
 async def test_download_falls_back_to_rest_name_when_mini_fails(
     monkeypatch, scanners, metadata_provider, tmp_path

tests/services/test_download_routing.py

@@ -20,6 +20,15 @@ def test_base_model_fallback_routes_to_unet():
     )
 
 
+@pytest.mark.parametrize("base_model", ["SVD XT", "Boogu", "Wan Video 3.0", "Flux 3 Video"])
+def test_new_diffusion_families_route_to_unet(base_model):
+    """DiT families from CivitAI's official baseModel list that plain
+    "Model"-typed files must not strand on the checkpoint roots."""
+    assert is_diffusion_model_download(
+        "checkpoint", file_types=["Model"], base_model=base_model
+    )
+
+
 def test_minimax_h3_routes_to_unet():
     """CivitAI model 2877206: type "Checkpoint", baseModel "MiniMax H3",
     all file entries typed "Model"."""
@@ -28,7 +37,19 @@ def test_minimax_h3_routes_to_unet():
     )
 
 
-@pytest.mark.parametrize("base_model", ["SDXL 1.0", "Illustrious", "SD 1.5", "SD 3.5 Large"])
+@pytest.mark.parametrize(
+    "base_model",
+    [
+        "SDXL 1.0",
+        "Illustrious",
+        "SD 1.5",
+        "SD 2.1 768",
+        "SD 3.5 Large",
+        "SDXL Turbo",
+        "Playground v2",
+        "Stable Cascade",
+    ],
+)
 def test_known_checkpoint_base_models_stay_on_checkpoint_roots(base_model):
     """CHECKPOINT_BASE_MODELS members never route to unet, even when the
     unknown-base-model default is diffusion."""