diff --git a/pdf-umbenenner-domain/src/main/java/de/gecheckt/pdf/umbenenner/domain/model/PreCheckFailed.java b/pdf-umbenenner-domain/src/main/java/de/gecheckt/pdf/umbenenner/domain/model/PreCheckFailed.java
index 6dbb158..31e5d92 100644
--- a/pdf-umbenenner-domain/src/main/java/de/gecheckt/pdf/umbenenner/domain/model/PreCheckFailed.java
+++ b/pdf-umbenenner-domain/src/main/java/de/gecheckt/pdf/umbenenner/domain/model/PreCheckFailed.java
@@ -13,14 +13,15 @@ import java.util.Objects;
  * <p>
  * Reasons include:
  * <ul>
- *   <li>{@link PreCheckFailureReason#NO_USABLE_TEXT} – extraction yielded no meaningful content</li>
- *   <li>{@link PreCheckFailureReason#PAGE_LIMIT_EXCEEDED} – document exceeds the configured page limit</li>
+ *   <li>{@link PreCheckFailureReason#NO_USABLE_TEXT} – The extracted text contains no meaningful content after normalization.</li>
+ *   <li>{@link PreCheckFailureReason#PAGE_LIMIT_EXCEEDED} – The document's page count exceeds the configured limit.</li>
+ *   <li>{@link PreCheckFailureReason#CONTENT_NOT_EXTRACTABLE} – The PDF content cannot be extracted due to structural issues.</li>
  * </ul>
  * <p>
  * A document with this decision will not proceed further in the current batch run.
  *
  * @param candidate the source document metadata
- * @param failureReason the reason for the pre-check failure
+ * @param failureReason the reason for the pre-check failure, must be non-null
  */
 public record PreCheckFailed(
     SourceDocumentCandidate candidate,