Custom providers update (#4099)

Co-authored-by: developerayo <shodipovi@gmail.com>
Co-authored-by: Douwe Osinga <douwe@squareup.com>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Zane Staggs <zane@squareup.com>

ui/desktop/src/components/settings/models/subcomponents/AddModelModal.tsx

@@ -159,11 +159,14 @@ export const AddModelModal = ({ onClose, setView }: AddModelModalProps) => {
 
         // Add the "Custom model" option to each provider group
         formattedModelOptions.forEach((group) => {
-          group.options.push({
-            value: 'custom',
-            label: 'Use custom model',
-            provider: group.options[0]?.provider,
-          });
+          const providerName = group.options[0]?.provider;
+          if (providerName && !providerName.startsWith('custom_')) {
+            group.options.push({
+              value: 'custom',
+              label: 'Use custom model',
+              provider: providerName,
+            });
+          }
         });
 
         setModelOptions(formattedModelOptions);