diff --git a/langchain4j-embeddings/src/main/java/dev/langchain4j/model/embedding/onnx/HuggingFaceTokenCountEstimator.java b/langchain4j-embeddings/src/main/java/dev/langchain4j/model/embedding/onnx/HuggingFaceTokenCountEstimator.java
index bf09b9a0..e8e3c2b3 100644
--- a/langchain4j-embeddings/src/main/java/dev/langchain4j/model/embedding/onnx/HuggingFaceTokenCountEstimator.java
+++ b/langchain4j-embeddings/src/main/java/dev/langchain4j/model/embedding/onnx/HuggingFaceTokenCountEstimator.java
@@ -107,7 +107,7 @@ public int estimateTokenCountInMessage(ChatMessage message) {
         } else if (message instanceof UserMessage userMessage) {
             return estimateTokenCountInText(userMessage.singleText());
         } else if (message instanceof AiMessage aiMessage) {
-            return estimateTokenCountInText(aiMessage.text());
+            return aiMessage.text() == null ? 0 : estimateTokenCountInText(aiMessage.text());
         } else if (message instanceof ToolExecutionResultMessage toolExecutionResultMessage) {
             return estimateTokenCountInText(toolExecutionResultMessage.text());
         } else {