diff --git a/orchestration/src/main/java/com/sap/ai/sdk/orchestration/OrchestrationClient.java b/orchestration/src/main/java/com/sap/ai/sdk/orchestration/OrchestrationClient.java
index 6ec9de4cf..386b29590 100644
--- a/orchestration/src/main/java/com/sap/ai/sdk/orchestration/OrchestrationClient.java
+++ b/orchestration/src/main/java/com/sap/ai/sdk/orchestration/OrchestrationClient.java
@@ -79,6 +79,16 @@ public OrchestrationClient(@Nonnull final HttpDestination destination) {
   @Nonnull
   public static CompletionRequestConfiguration toCompletionPostRequest(
       @Nonnull final OrchestrationPrompt prompt, @Nonnull final OrchestrationModuleConfig config) {
+    if (prompt.getMessages().size() == 1 && prompt.getMessages().get(0) instanceof UserMessage m) {
+      val items = m.content().items();
+      if (items.size() == 1 && items.get(0) instanceof TextItem t) {
+        val JSON_SCHEMA = "https://json-schema.org/draft/2020-12/schema";
+        if (t.text().contains(JSON_SCHEMA) && config.getTemplateConfig() != null) {
+          log.warn("Combination of `entity(...)` and `withTemplateConfig(...)` is not supported.");
+        }
+      }
+    }
+
     return ConfigToRequestTransformer.toCompletionPostRequest(prompt, config);
   }