diff --git a/src/cpp/src/llm_pipeline_static.cpp b/src/cpp/src/llm_pipeline_static.cpp
index 4bb84dfc05..c2c449ddd0 100644
--- a/src/cpp/src/llm_pipeline_static.cpp
+++ b/src/cpp/src/llm_pipeline_static.cpp
@@ -413,7 +413,8 @@ ModelDesc get_modeldesc_from_json(const std::filesystem::path& filepath) {
     if (config_data.contains("_name_or_path")) {
         desc.name_or_path = config_data["_name_or_path"].get<std::string>();
     }
-    desc.num_key_value_heads = config_data["num_key_value_heads"].get<int>();
+    desc.num_key_value_heads = config_data.contains("num_key_value_heads")
+        ? config_data["num_key_value_heads"].get<int>() : -1;
     return desc;
 }