1 files changed, 4 insertions, 2 deletions
diff --git a/model-evaluation/src/main/java/ai/vespa/models/evaluation/OnnxModel.java b/model-evaluation/src/main/java/ai/vespa/models/evaluation/OnnxModel.java
index b86cf60318a..73c5eb36539 100644
--- a/model-evaluation/src/main/java/ai/vespa/models/evaluation/OnnxModel.java
+++ b/model-evaluation/src/main/java/ai/vespa/models/evaluation/OnnxModel.java
@@ -48,11 +48,13 @@ class OnnxModel implements AutoCloseable {
     final List<OutputSpec> outputSpecs = new ArrayList<>();
 
     void addInputMapping(String onnxName, String source) {
-        assert(referencedEvaluator == null);
+        if (referencedEvaluator != null)
+            throw new IllegalStateException("input mapping must be added before load()");
         inputSpecs.add(new InputSpec(onnxName, source));
     }
     void addOutputMapping(String onnxName, String outputAs) {
-        assert(referencedEvaluator == null);
+        if (referencedEvaluator != null)
+            throw new IllegalStateException("output mapping must be added before load()");
         outputSpecs.add(new OutputSpec(onnxName, outputAs));
     }