fix: default SLM_MODEL_NAME to openai/gpt-oss-20b for NVIDIA Build API

app.py

@@ -75,8 +75,8 @@ LOGGER = logging.getLogger("razorshield-app")
 # =============================================================================
 
 SLM_MODEL_NAME = os.getenv(
-    "SLM_MODEL",
-    "Qwen/Qwen2.5-0.5B-Instruct",
+    "NVIDIA_MODEL",
+    os.getenv("SLM_MODEL", "openai/gpt-oss-20b"),
 )
 
 POLICY_MODE_DEFAULT = os.getenv(

src/explanation/model_loader.py

@@ -25,6 +25,9 @@ class SLMModelLoader:
         max_new_tokens: int | None = None,
         temperature: float | None = None,
     ):
+        if os.getenv("NVIDIA_API_KEY") and os.getenv("NVIDIA_API_KEY").strip():
+            if not model_name or "Qwen" in model_name:
+                model_name = os.getenv("NVIDIA_MODEL", "openai/gpt-oss-20b")
         self.model_name = model_name or os.getenv("NVIDIA_MODEL", "openai/gpt-oss-20b")
         self.max_tokens = max_new_tokens or int(os.getenv("SLM_MAX_TOKENS", "4096"))
         self.temperature = temperature or float(os.getenv("SLM_TEMPERATURE", "1.0"))