diff --git a/api/endpoints/environment_router.py b/api/endpoints/environment_router.py
index aafb2c5..3b1f6b0 100644
--- a/api/endpoints/environment_router.py
+++ b/api/endpoints/environment_router.py
@@ -91,6 +91,18 @@ async def update_environment(
     update_data = env_update.model_dump(exclude_unset=True)
     if not update_data:
         return env
+
+    # Verify assets exist if provided
+    if "asset_ids" in update_data:
+        if update_data["asset_ids"] is None:
+            del update_data["asset_ids"]
+        elif update_data["asset_ids"]:
+            # Verify all assets exist using batch check
+            assets = await dao.assets.get_assets_by_ids(update_data["asset_ids"])
+            if len(assets) != len(update_data["asset_ids"]):
+                found_ids = {a.id for a in assets}
+                missing_ids = [aid for aid in update_data["asset_ids"] if aid not in found_ids]
+                raise HTTPException(status_code=400, detail=f"Some assets not found: {missing_ids}")
         
     success = await dao.environments.update_env(env_id, update_data)
     if not success:
diff --git a/api/models/EnvironmentRequest.py b/api/models/EnvironmentRequest.py
index 2057b08..430bc0a 100644
--- a/api/models/EnvironmentRequest.py
+++ b/api/models/EnvironmentRequest.py
@@ -12,6 +12,7 @@ class EnvironmentCreate(BaseModel):
 class EnvironmentUpdate(BaseModel):
     name: Optional[str] = Field(None, min_length=1)
     description: Optional[str] = None
+    asset_ids: Optional[List[str]] = None
 
 
 class AssetToEnvironment(BaseModel):
diff --git a/repos/assets_repo.py b/repos/assets_repo.py
index 07ae690..7df5dba 100644
--- a/repos/assets_repo.py
+++ b/repos/assets_repo.py
@@ -102,7 +102,7 @@ class AssetsRepo:
 
         return assets
 
-    async def get_asset(self, asset_id: str, with_data: bool = True) -> Asset:
+    async def get_asset(self, asset_id: str, with_data: bool = True) -> Optional[Asset]:
         projection = None
         if not with_data:
              projection = {"data": 0, "thumbnail": 0}
@@ -182,7 +182,9 @@ class AssetsRepo:
         return await self.collection.count_documents(filter)
 
     async def get_assets_by_ids(self, asset_ids: List[str]) -> List[Asset]:
-        object_ids = [ObjectId(asset_id) for asset_id in asset_ids]
+        object_ids = [ObjectId(asset_id) for asset_id in asset_ids if ObjectId.is_valid(asset_id)]
+        if not object_ids:
+            return []
         res = self.collection.find({"_id": {"$in": object_ids}}, {"data": 0}) # Exclude data but maybe allow thumbnail if small?
         # Original excluded thumbnail too.
         assets = []