diff --git a/src/vs/workbench/contrib/chat/common/languageModels.ts b/src/vs/workbench/contrib/chat/common/languageModels.ts
index a0dd51069000a..631d6996240a0 100644
--- a/src/vs/workbench/contrib/chat/common/languageModels.ts
+++ b/src/vs/workbench/contrib/chat/common/languageModels.ts
@@ -877,10 +877,11 @@ export class LanguageModelsService implements ILanguageModelsService {
 					continue;
 				}
 
-				// For the default vendor, groups that only have per-model config
-				// should not trigger a separate model resolution call.
+				// For vendors without a configuration schema whose models were already
+				// resolved in the initial (groupless) load, groups only carry per-model
+				// settings and should not trigger a separate model resolution call.
 				// Instead, apply the per-model config to the already-resolved models.
-				if (vendor.isDefault && !vendor.configuration) {
+				if (!vendor.configuration && allModels.length > 0) {
 					if (group.settings) {
 						for (const model of allModels) {
 							const modelConfig = group.settings[model.metadata.id];
@@ -1119,7 +1120,9 @@ export class LanguageModelsService implements ILanguageModelsService {
 			}
 		} else if (Object.keys(updatedConfig).length > 0) {
 			// Only create a new group if there's non-default config
-			const vendor = this.getVendors().find(v => v.vendor === metadata.vendor);
+			// Use _vendors directly instead of getVendors() which filters by `when` clause,
+			// because we need to store config for all vendors regardless of UI visibility.
+			const vendor = this._vendors.get(metadata.vendor);
 			if (!vendor) {
 				return;
 			}