Merge pull request #1132 from willmiao/fix/diffusion-routing-default

fix(downloads): route unknown checkpoint baseModels to diffusion models by default

docs/i18n-translation-guidelines.md

@@ -103,6 +103,15 @@ Locales: `en`, `zh-CN`, `zh-TW`, `ja`, `ko`, `fr`, `de`, `es`, `ru`, `he` (RTL).
 > failure-table conventions; reuse each locale's existing renderings of those sibling keys).
 > All 9 locales are translated in the same pass (terminology in §2, "Sidecar storage feature").
 
+> **Status (2026-10, unknown base model routing):** the download-routing inversion added
+> 4 keys (`settings.unknownBaseModelRouting.label`, `.help`, `.options.diffusionModel`,
+> `.options.checkpoint`) — the option labels reuse each locale's existing
+> `checkpoints.modelTypes.diffusion_model` / `.checkpoint` renderings. The same pass also
+> translated the leftover `doctor.issues.sidecar_mirror_orphans.title` ("Centralized
+> Sidecars", §2 "Sidecar storage feature" terminology). All 9 locales are translated,
+> so the "no remaining placeholders" claim holds again. Terminology in §2, "Download
+> routing feature".
+
 ---
 
 ## 1. Hard rules (do not violate)
@@ -543,6 +552,25 @@ short and imperative and do not append a keyboard hint in any locale.
 
 The grip itself is an icon and is never translated.
 
+### Download routing feature (unknown base model routing)
+
+The `settings.unknownBaseModelRouting.*` keys (Settings → Library → Folder Settings) decide
+which library a checkpoint download lands in when CivitAI reports a baseModel that is in
+neither the known-checkpoint nor the known-diffusion-model list. The option labels reuse
+each locale's `checkpoints.modelTypes.diffusion_model` / `.checkpoint` renderings
+(model-type names, R3 — ja/ko keep the Latin loanword), pluralized only where the locale
+pluralizes (de Diffusionsmodelle, es Modelos de difusión, fr Modèles de diffusion,
+ru Диффузионные модели, he מודלי דיפוזיה; CJK stays singular, "Checkpoint(s)" follows
+`header.navigation.checkpoints`).
+
+| Term | Rendering |
+|---|---|
+| routing (noun, of a download into a library) | zh-CN 路由 · zh-TW 路由 · ja 振り分け · ko 라우팅 · fr routage · de Routing · es enrutamiento · ru маршрутизация · he ניתוב |
+| unknown base model | zh-CN 未知基础模型 · zh-TW 未知基礎模型 · ja 不明なベースモデル · ko 알 수 없는 베이스 모델 · fr modèle de base inconnu · de unbekanntes Basismodell · es modelo base desconocido · ru неизвестная базовая модель · he מודל בסיס לא מוכר |
+
+The baseModel family names in the help text (`SD 1.x/2.x/3.x, SDXL, Pony, Illustrious,
+NoobAI`) are CivitAI baseModel values and stay verbatim in every locale.
+
 ---
 
 ## 3. Cross-cutting confusion hot-spots (must-fix list)

locales/de.json

@@ -353,6 +353,14 @@
             "placeholder": "Leer lassen, um aria2c aus dem PATH zu verwenden"
         },
         "aria2HelpLink": "Erfahren Sie, wie Sie das aria2-Download-Backend einrichten",
+        "unknownBaseModelRouting": {
+            "label": "Routing unbekannter Basismodelle",
+            "help": "Legt fest, wohin Checkpoint-Downloads gehen, wenn CivitAI ein Basismodell meldet, das weder ein bekanntes Checkpoint (SD 1.x/2.x/3.x, SDXL, Pony, Illustrious, NoobAI) noch ein bekanntes Diffusionsmodell ist. Neue Diffusionsarchitekturen erscheinen häufig, daher ist das Routing zu Diffusionsmodellen meist korrekt.",
+            "options": {
+                "diffusionModel": "Diffusionsmodelle",
+                "checkpoint": "Checkpoints"
+            }
+        },
         "civitaiHostBanner": {
             "title": "CivitAI-Host-Einstellung verfügbar",
             "content": "CivitAI verwendet jetzt civitai.com für SFW-Inhalte und civitai.red für uneingeschränkte Inhalte. In den Einstellungen können Sie ändern, welche Seite standardmäßig geöffnet wird.",
@@ -2770,7 +2778,7 @@
                 "title": "Konflikte durch doppelte Dateinamen"
             },
             "sidecar_mirror_orphans": {
-                "title": "[TODO: Translate] Centralized Sidecars"
+                "title": "Zentralisierte Sidecar-Dateien"
             },
             "ui_version": {
                 "title": "UI-Version"

locales/en.json

@@ -353,6 +353,14 @@
       "placeholder": "Leave empty to use aria2c from PATH"
     },
     "aria2HelpLink": "Learn how to set up the aria2 download backend",
+    "unknownBaseModelRouting": {
+      "label": "Unknown base model routing",
+      "help": "Decides where checkpoint downloads go when CivitAI reports a base model that is neither a known checkpoint (SD 1.x/2.x/3.x, SDXL, Pony, Illustrious, NoobAI) nor a known diffusion model. New diffusion architectures appear frequently, so routing them to diffusion models is usually correct.",
+      "options": {
+        "diffusionModel": "Diffusion models",
+        "checkpoint": "Checkpoints"
+      }
+    },
     "civitaiHostBanner": {
       "title": "CivitAI host preference available",
       "content": "CivitAI now uses civitai.com for SFW content and civitai.red for unrestricted content. You can change which site opens by default in Settings.",

locales/es.json

@@ -353,6 +353,14 @@
             "placeholder": "Déjalo vacío para usar aria2c desde el PATH"
         },
         "aria2HelpLink": "Aprende a configurar el backend de descarga aria2",
+        "unknownBaseModelRouting": {
+            "label": "Enrutamiento de modelos base desconocidos",
+            "help": "Decide a dónde van las descargas de Checkpoint cuando CivitAI informa de un modelo base que no es ni un Checkpoint conocido (SD 1.x/2.x/3.x, SDXL, Pony, Illustrious, NoobAI) ni un modelo de difusión conocido. Las nuevas arquitecturas de difusión aparecen con frecuencia, por lo que enrutarlas a modelos de difusión suele ser correcto.",
+            "options": {
+                "diffusionModel": "Modelos de difusión",
+                "checkpoint": "Checkpoints"
+            }
+        },
         "civitaiHostBanner": {
             "title": "Preferencia de host de CivitAI disponible",
             "content": "CivitAI ahora usa civitai.com para contenido SFW y civitai.red para contenido sin restricciones. Puedes cambiar en Ajustes qué sitio se abre por defecto.",
@@ -2770,7 +2778,7 @@
                 "title": "Conflictos de nombres de archivo duplicados"
             },
             "sidecar_mirror_orphans": {
-                "title": "[TODO: Translate] Centralized Sidecars"
+                "title": "Archivos sidecar centralizados"
             },
             "ui_version": {
                 "title": "Versión de la interfaz"

locales/fr.json

@@ -353,6 +353,14 @@
             "placeholder": "Laisser vide pour utiliser aria2c depuis le PATH"
         },
         "aria2HelpLink": "Apprenez à configurer le backend de téléchargement aria2",
+        "unknownBaseModelRouting": {
+            "label": "Routage des modèles de base inconnus",
+            "help": "Détermine où vont les téléchargements de Checkpoint lorsque CivitAI signale un modèle de base qui n’est ni un Checkpoint connu (SD 1.x/2.x/3.x, SDXL, Pony, Illustrious, NoobAI) ni un modèle de diffusion connu. De nouvelles architectures de diffusion apparaissent fréquemment, donc les router vers les modèles de diffusion est généralement correct.",
+            "options": {
+                "diffusionModel": "Modèles de diffusion",
+                "checkpoint": "Checkpoints"
+            }
+        },
         "civitaiHostBanner": {
             "title": "Préférence d’hôte CivitAI disponible",
             "content": "CivitAI utilise désormais civitai.com pour le contenu SFW et civitai.red pour le contenu sans restriction. Vous pouvez modifier dans les paramètres le site ouvert par défaut.",
@@ -2770,7 +2778,7 @@
                 "title": "Conflits de noms de fichiers en double"
             },
             "sidecar_mirror_orphans": {
-                "title": "[TODO: Translate] Centralized Sidecars"
+                "title": "Fichiers sidecar centralisés"
             },
             "ui_version": {
                 "title": "Version de l'interface"

locales/he.json

@@ -353,6 +353,14 @@
             "placeholder": "השאר ריק כדי להשתמש ב-aria2c מתוך ה-PATH"
         },
         "aria2HelpLink": "למד כיצד להגדיר את מנוע ההורדה aria2",
+        "unknownBaseModelRouting": {
+            "label": "ניתוב מודל בסיס לא מוכר",
+            "help": "קובע לאן מועברות הורדות של Checkpoint כאשר CivitAI מדווח על מודל בסיס שהוא לא Checkpoint מוכר (SD 1.x/2.x/3.x, SDXL, Pony, Illustrious, NoobAI) ולא מודל דיפוזיה מוכר. ארכיטקטורות דיפוזיה חדשות מופיעות לעיתים קרובות, ולכן ניתוב שלהן למודלי דיפוזיה הוא בדרך כלל הנכון.",
+            "options": {
+                "diffusionModel": "מודלי דיפוזיה",
+                "checkpoint": "Checkpoints"
+            }
+        },
         "civitaiHostBanner": {
             "title": "העדפת מארח CivitAI זמינה",
             "content": "CivitAI משתמש כעת ב-civitai.com עבור תוכן SFW וב-civitai.red עבור תוכן ללא הגבלות. ניתן לשנות בהגדרות איזה אתר ייפתח כברירת מחדל.",
@@ -2770,7 +2778,7 @@
                 "title": "התנגשויות שמות קבצים כפולים"
             },
             "sidecar_mirror_orphans": {
-                "title": "[TODO: Translate] Centralized Sidecars"
+                "title": "קבצי לוואי מרוכזים"
             },
             "ui_version": {
                 "title": "גרסת הממשק"

locales/ja.json

@@ -353,6 +353,14 @@
             "placeholder": "空欄のままにすると PATH 上の aria2c を使用します"
         },
         "aria2HelpLink": "aria2 ダウンロードバックエンドの設定方法",
+        "unknownBaseModelRouting": {
+            "label": "不明なベースモデルの振り分け",
+            "help": "CivitAIが報告するベースモデルが既知のCheckpoint（SD 1.x/2.x/3.x、SDXL、Pony、Illustrious、NoobAI）でも既知のDiffusion Modelでもない場合に、Checkpointのダウンロードの保存先を決定します。新しい拡散アーキテクチャは頻繁に登場するため、通常はDiffusion Modelへの振り分けが正しい選択です。",
+            "options": {
+                "diffusionModel": "Diffusion Model",
+                "checkpoint": "Checkpoint"
+            }
+        },
         "civitaiHostBanner": {
             "title": "CivitAI ホスト設定を利用できます",
             "content": "CivitAI は現在、SFW コンテンツには civitai.com、制限なしコンテンツには civitai.red を使用しています。設定で既定で開くサイトを変更できます。",
@@ -2770,7 +2778,7 @@
                 "title": "ファイル名重複競合"
             },
             "sidecar_mirror_orphans": {
-                "title": "[TODO: Translate] Centralized Sidecars"
+                "title": "集中保存のサイドカーファイル"
             },
             "ui_version": {
                 "title": "UI バージョン"

locales/ko.json

@@ -353,6 +353,14 @@
             "placeholder": "비워 두면 PATH의 aria2c를 사용합니다"
         },
         "aria2HelpLink": "aria2 다운로드 백엔드 설정 방법 알아보기",
+        "unknownBaseModelRouting": {
+            "label": "알 수 없는 베이스 모델 라우팅",
+            "help": "CivitAI가 보고한 베이스 모델이 알려진 Checkpoint(SD 1.x/2.x/3.x, SDXL, Pony, Illustrious, NoobAI)도 알려진 Diffusion Model도 아닐 때 Checkpoint 다운로드의 저장 위치를 결정합니다. 새로운 확산 아키텍처는 자주 등장하므로 일반적으로 Diffusion Model로 라우팅하는 것이 올바릅니다.",
+            "options": {
+                "diffusionModel": "Diffusion Model",
+                "checkpoint": "Checkpoint"
+            }
+        },
         "civitaiHostBanner": {
             "title": "CivitAI 호스트 기본 설정 사용 가능",
             "content": "이제 CivitAI는 SFW 콘텐츠에 civitai.com을, 무제한 콘텐츠에 civitai.red를 사용합니다. 설정에서 기본으로 열 사이트를 변경할 수 있습니다.",
@@ -2770,7 +2778,7 @@
                 "title": "파일명 중복 충돌"
             },
             "sidecar_mirror_orphans": {
-                "title": "[TODO: Translate] Centralized Sidecars"
+                "title": "중앙 집중식 사이드카 파일"
             },
             "ui_version": {
                 "title": "UI 버전"

locales/ru.json

@@ -353,6 +353,14 @@
             "placeholder": "Оставьте пустым, чтобы использовать aria2c из PATH"
         },
         "aria2HelpLink": "Узнайте, как настроить сервер загрузки aria2",
+        "unknownBaseModelRouting": {
+            "label": "Маршрутизация неизвестных базовых моделей",
+            "help": "Определяет, куда отправляются загрузки Checkpoint, когда CivitAI сообщает базовую модель, которая не является ни известным Checkpoint (SD 1.x/2.x/3.x, SDXL, Pony, Illustrious, NoobAI), ни известной диффузионной моделью. Новые диффузионные архитектуры появляются часто, поэтому маршрутизация их в диффузионные модели обычно правильная.",
+            "options": {
+                "diffusionModel": "Диффузионные модели",
+                "checkpoint": "Checkpoints"
+            }
+        },
         "civitaiHostBanner": {
             "title": "Доступна настройка хоста CivitAI",
             "content": "Теперь CivitAI использует civitai.com для контента SFW и civitai.red для контента без ограничений. В настройках можно изменить, какой сайт открывать по умолчанию.",
@@ -2770,7 +2778,7 @@
                 "title": "Конфликты дублирующихся имён файлов"
             },
             "sidecar_mirror_orphans": {
-                "title": "[TODO: Translate] Centralized Sidecars"
+                "title": "Централизованные sidecar-файлы"
             },
             "ui_version": {
                 "title": "Версия интерфейса"

locales/zh-CN.json

@@ -353,6 +353,14 @@
             "placeholder": "留空则使用 PATH 中的 aria2c"
         },
         "aria2HelpLink": "了解如何配置 aria2 下载后端",
+        "unknownBaseModelRouting": {
+            "label": "未知基础模型路由",
+            "help": "当 CivitAI 报告的基础模型既不是已知的 Checkpoint（SD 1.x/2.x/3.x、SDXL、Pony、Illustrious、NoobAI），也不是已知的扩散模型时，决定 Checkpoint 下载的保存位置。新的扩散架构频繁出现，因此将其路由到扩散模型通常是正确的。",
+            "options": {
+                "diffusionModel": "扩散模型",
+                "checkpoint": "Checkpoint"
+            }
+        },
         "civitaiHostBanner": {
             "title": "已提供 CivitAI 站点偏好设置",
             "content": "CivitAI 现在使用 civitai.com 提供 SFW 内容，使用 civitai.red 提供无限制内容。你可以在设置中更改默认打开的站点。",
@@ -2770,7 +2778,7 @@
                 "title": "文件名重复冲突"
             },
             "sidecar_mirror_orphans": {
-                "title": "[TODO: Translate] Centralized Sidecars"
+                "title": "集中存储的附属文件"
             },
             "ui_version": {
                 "title": "UI 版本"

locales/zh-TW.json

@@ -353,6 +353,14 @@
             "placeholder": "留空則使用 PATH 中的 aria2c"
         },
         "aria2HelpLink": "了解如何設定 aria2 下載後端",
+        "unknownBaseModelRouting": {
+            "label": "未知基礎模型路由",
+            "help": "當 CivitAI 回報的基礎模型既不是已知的 Checkpoint（SD 1.x/2.x/3.x、SDXL、Pony、Illustrious、NoobAI），也不是已知的擴散模型時，決定 Checkpoint 下載的儲存位置。新的擴散架構頻繁出現，因此將其路由到擴散模型通常是正確的。",
+            "options": {
+                "diffusionModel": "擴散模型",
+                "checkpoint": "Checkpoint"
+            }
+        },
         "civitaiHostBanner": {
             "title": "已提供 CivitAI 站點偏好設定",
             "content": "CivitAI 現在使用 civitai.com 提供 SFW 內容，使用 civitai.red 提供無限制內容。您可以在設定中變更預設開啟的站點。",
@@ -2770,7 +2778,7 @@
                 "title": "檔案名稱重複衝突"
             },
             "sidecar_mirror_orphans": {
-                "title": "[TODO: Translate] Centralized Sidecars"
+                "title": "集中儲存的附屬檔案"
             },
             "ui_version": {
                 "title": "UI 版本"

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
 
@@ -96,10 +101,15 @@ class DownloadRoutingHandler:
                 }
             )
 
+        from ...services.settings_manager import get_settings_manager
+
         is_diffusion = is_diffusion_model_download(
             model_type,
             file_types=(str(t) for t in file_types),
             base_model=base_model,
+            unknown_base_model_default=get_settings_manager().get(
+                "unknown_base_model_routing", "diffusion_model"
+            ),
         )
         return web.json_response(
             {

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"
@@ -1670,6 +1674,9 @@ class DownloadManager:
                 model_type,
                 file_types=(f.get("type", "") for f in version_info.get("files", [])),
                 base_model=base_model_value,
+                unknown_base_model_default=get_settings_manager().get(
+                    "unknown_base_model_routing", "diffusion_model"
+                ),
             )
 
             # Existence check after the metadata fetch (#1058):

py/services/download_routing.py

@@ -13,6 +13,7 @@ import logging
 from typing import Iterable, Optional
 
 from ..utils.constants import (
+    CHECKPOINT_BASE_MODELS,
     CIVITAI_FILE_TYPE_TO_OTHER_SUB_TYPE,
     CIVITAI_TYPE_TO_OTHER_SUB_TYPE,
     DIFFUSION_MODEL_BASE_MODELS,
@@ -24,17 +25,27 @@ logger = logging.getLogger(__name__)
 # model (loaded via UNETLoader in ComfyUI) rather than a full checkpoint.
 DIFFUSION_FILE_TYPES = frozenset({"UNet", "Diffusion Model"})
 
+# Allowed values for the "unknown_base_model_routing" setting / the
+# unknown_base_model_default parameter below.
+ROUTING_DIFFUSION_MODEL = "diffusion_model"
+ROUTING_CHECKPOINT = "checkpoint"
+
 
 def is_diffusion_model_download(
     model_type: str,
     file_types: Iterable[str] = (),
     base_model: str = "",
+    unknown_base_model_default: str = ROUTING_DIFFUSION_MODEL,
 ) -> bool:
     """Return True when a download should be routed to the unet roots.
 
     Only applies to downloads initiated from the checkpoint library.
     Priority: (1) any file has type "UNet" or "Diffusion Model" (the more
-    direct signal from CivitAI), (2) baseModel is a known diffusion model.
+    direct signal from CivitAI), (2) baseModel is a known diffusion model,
+    (3) baseModel is a known full checkpoint -> not diffusion, (4) unknown
+    or empty baseModel -> the ``unknown_base_model_default`` setting, which
+    defaults to diffusion because the set of true checkpoint families is
+    closed while new DiT base models appear all the time.
     """
     if model_type != "checkpoint":
         return False
@@ -54,7 +65,16 @@ def is_diffusion_model_download(
         )
         return True
 
-    return False
+    if base_model in CHECKPOINT_BASE_MODELS:
+        return False
+
+    is_diffusion = unknown_base_model_default != ROUTING_CHECKPOINT
+    logger.info(
+        "baseModel '%s' is unknown, routing to %s folder (unknown_base_model_routing)",
+        base_model,
+        "unet" if is_diffusion else "checkpoint",
+    )
+    return is_diffusion
 
 
 def resolve_other_download_sub_type(

py/services/settings_manager.py

@@ -130,6 +130,9 @@ DEFAULT_SETTINGS: Dict[str, Any] = {
     "metadata_refresh_skip_paths": [],
     "skip_previously_downloaded_model_versions": False,
     "download_skip_base_models": [],
+    # Routing target for checkpoint downloads whose baseModel is neither a
+    # known diffusion model nor a known full checkpoint (CHECKPOINT_BASE_MODELS).
+    "unknown_base_model_routing": "diffusion_model",
     "backup_auto_enabled": True,
     "backup_retention_count": 5,
     "use_new_license_icons": True,
@@ -1628,6 +1631,16 @@ class SettingsManager:
                 return normalized
         return "alongside"
 
+    @staticmethod
+    def _normalize_unknown_base_model_routing(value: Any) -> str:
+        """Return a valid unknown-base-model routing target, falling back to ``diffusion_model``."""
+
+        if isinstance(value, str):
+            normalized = value.strip().lower()
+            if normalized in ("diffusion_model", "checkpoint"):
+                return normalized
+        return "diffusion_model"
+
     def _refresh_sidecar_storage_config(self) -> None:
         """Rebuild dependent config state after sidecar storage settings change."""
 
@@ -1840,6 +1853,8 @@ class SettingsManager:
             self._migrate_recipes_directory(current_recipes_dir, target_recipes_dir)
         elif key == "sidecar_storage_mode":
             value = self._normalize_sidecar_storage_mode(value)
+        elif key == "unknown_base_model_routing":
+            value = self._normalize_unknown_base_model_routing(value)
         elif key == "sidecar_storage_path":
             value = self._normalize_recipes_path_value(value)
         self.settings[key] = value

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",
@@ -368,11 +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
@@ -380,6 +391,53 @@ DIFFUSION_MODEL_BASE_MODELS = frozenset(
     ]
 )
 
+# baseModel values from CivitAI that are true full checkpoints (loaded via
+# 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). 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
+        "SD 1.4",
+        "SD 1.5",
+        "SD 1.5 LCM",
+        "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",
+        "SD 3.5 Medium",
+        "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",
+    ]
+)
+
 # Supported baseModel values for download exclusion settings.
 # Keep this aligned with static/js/utils/constants.js, excluding the generic "Other" value.
 SUPPORTED_DOWNLOAD_SKIP_BASE_MODELS = frozenset(

static/js/managers/SettingsManager.js

@@ -1053,6 +1053,11 @@ export class SettingsManager {
             downloadBackendSelect.value = state.global.settings.download_backend || 'python';
         }
 
+        const unknownBaseModelRoutingSelect = document.getElementById('unknownBaseModelRouting');
+        if (unknownBaseModelRoutingSelect) {
+            unknownBaseModelRoutingSelect.value = state.global.settings.unknown_base_model_routing || 'diffusion_model';
+        }
+
         const aria2cPathInput = document.getElementById('aria2cPath');
         if (aria2cPathInput) {
             aria2cPathInput.value = state.global.settings.aria2c_path || '';

static/js/state/index.js

@@ -60,6 +60,7 @@ const DEFAULT_SETTINGS_BASE = Object.freeze({
     metadata_refresh_skip_paths: [],
     skip_previously_downloaded_model_versions: false,
     download_skip_base_models: [],
+    unknown_base_model_routing: 'diffusion_model',
     backup_auto_enabled: true,
     backup_retention_count: 5,
     sidecar_storage_mode: 'alongside',

templates/components/modals/settings/library.html

@@ -26,6 +26,11 @@
 
         {{ sm.setting_select('defaultUnetRoot', 'default_unet_root', 'settings.folderSettings.defaultUnetRoot', [], 'settings.folderSettings.defaultUnetRootHelp') }}
 
+        {{ sm.setting_select('unknownBaseModelRouting', 'unknown_base_model_routing', 'settings.unknownBaseModelRouting.label', [
+            ('diffusion_model', 'settings.unknownBaseModelRouting.options.diffusionModel'),
+            ('checkpoint', 'settings.unknownBaseModelRouting.options.checkpoint'),
+        ], 'settings.unknownBaseModelRouting.help') }}
+
         {{ sm.setting_select('defaultEmbeddingRoot', 'default_embedding_root', 'settings.folderSettings.defaultEmbeddingRoot', [], 'settings.folderSettings.defaultEmbeddingRootHelp') }}
 
         {{ sm.setting_toggle('enableOtherModels', 'enable_other_models', 'settings.folderSettings.enableOtherModels', 'settings.folderSettings.enableOtherModelsHelp') }}

tests/routes/test_download_routing_handlers.py

@@ -73,6 +73,57 @@ async def test_regular_checkpoint_stays_on_checkpoint_root():
     assert payload["root_kind"] == "checkpoint"
 
 
+@pytest.mark.asyncio
+async def test_unknown_base_model_routes_to_unet_by_default():
+    handler = DownloadRoutingHandler()
+    response = await handler.get_download_routing(
+        FakeRequest(
+            {
+                "model_type": "checkpoint",
+                "base_model": "Brand New Arch",
+                "file_types": ["Model"],
+            }
+        )
+    )
+    payload = json.loads(response.text)
+    assert payload["is_diffusion_model"] is True
+    assert payload["root_kind"] == "unet"
+
+
+@pytest.mark.asyncio
+async def test_unknown_base_model_honors_checkpoint_routing_setting():
+    get_settings_manager().settings["unknown_base_model_routing"] = "checkpoint"
+
+    handler = DownloadRoutingHandler()
+    response = await handler.get_download_routing(
+        FakeRequest(
+            {
+                "model_type": "checkpoint",
+                "base_model": "Brand New Arch",
+                "file_types": ["Model"],
+            }
+        )
+    )
+    payload = json.loads(response.text)
+    assert payload["is_diffusion_model"] is False
+    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
@@ -2209,7 +2257,7 @@ async def test_download_falls_back_to_rest_name_when_mini_fails(
     metadata_provider.payload = {
         "id": 42,
         "model": {"type": "Checkpoint", "tags": ["fantasy"]},
-        "baseModel": "BaseModel",
+        "baseModel": "SDXL 1.0",
         "creator": {"username": "Author"},
         "files": [
             {

tests/services/test_download_routing.py

@@ -20,9 +20,68 @@ def test_base_model_fallback_routes_to_unet():
     )
 
 
-def test_regular_checkpoint_stays_on_checkpoint_roots():
+@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"."""
+    assert is_diffusion_model_download(
+        "checkpoint", file_types=["Model"], base_model="MiniMax H3"
+    )
+
+
+@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."""
     assert not is_diffusion_model_download(
-        "checkpoint", file_types=["Model"], base_model="SDXL 1.0"
+        "checkpoint", file_types=["Model"], base_model=base_model
+    )
+
+
+def test_unknown_base_model_defaults_to_unet():
+    """New DiT families appear faster than the allowlist can track them, so
+    unknown baseModels route to unet by default."""
+    assert is_diffusion_model_download(
+        "checkpoint", file_types=["Model"], base_model="Brand New Arch"
+    )
+
+
+def test_unknown_base_model_honors_checkpoint_setting():
+    assert not is_diffusion_model_download(
+        "checkpoint",
+        file_types=["Model"],
+        base_model="Brand New Arch",
+        unknown_base_model_default="checkpoint",
+    )
+
+
+def test_unknown_base_model_checkpoint_setting_still_loses_to_file_type():
+    """The file-type signal stays first regardless of the setting."""
+    assert is_diffusion_model_download(
+        "checkpoint",
+        file_types=["Diffusion Model"],
+        base_model="SDXL 1.0",
+        unknown_base_model_default="checkpoint",
     )
 
 
@@ -35,9 +94,15 @@ def test_non_checkpoint_types_never_route_to_unet():
     )
 
 
-def test_empty_inputs_stay_on_checkpoint_roots():
+def test_empty_base_model_follows_unknown_default():
-    assert not is_diffusion_model_download("checkpoint")
+    assert is_diffusion_model_download("checkpoint")
-    assert not is_diffusion_model_download("checkpoint", file_types=[], base_model="")
+    assert is_diffusion_model_download("checkpoint", file_types=[], base_model="")
+    assert not is_diffusion_model_download(
+        "checkpoint",
+        file_types=[],
+        base_model="",
+        unknown_base_model_default="checkpoint",
+    )
 
 
 from py.services.download_routing import resolve_other_download_sub_type

tests/services/test_settings_manager.py

@@ -1300,6 +1300,21 @@ def test_setting_download_skip_base_models_normalizes_string_input(manager):
     assert manager.get("download_skip_base_models") == ["SDXL 1.0", "Pony"]
 
 
+def test_unknown_base_model_routing_defaults_to_diffusion_model(manager):
+    assert manager.get("unknown_base_model_routing") == "diffusion_model"
+
+
+def test_unknown_base_model_routing_is_normalized(manager):
+    manager.set("unknown_base_model_routing", "CHECKPOINT")
+    assert manager.get("unknown_base_model_routing") == "checkpoint"
+
+    manager.set("unknown_base_model_routing", "bogus")
+    assert manager.get("unknown_base_model_routing") == "diffusion_model"
+
+    manager.set("unknown_base_model_routing", None)
+    assert manager.get("unknown_base_model_routing") == "diffusion_model"
+
+
 def test_skip_previously_downloaded_model_versions_defaults_false(manager):
     assert manager.get_skip_previously_downloaded_model_versions() is False