--- before/model_gateway.py
+++ model_gateway.py
@@ -270,6 +270,12 @@
 
     config = outlet.config
     kind = outlet.kind
+    config_error = model_protocol.chat_config_error(
+        kind, config.get("base_url") or "", config.get("model") or "",
+    )
+    if config_error:
+        return {"provider": outlet.name, "text": "", "latency_ms": 0,
+                "error": config_error}
     timeout = min(float(config.get("timeout_ms") or 30000) / 1000.0, deadline)
 
     try: