diff --git a/src/main/java/com/google/jspecify/nullness/NullSpecChecker.java b/src/main/java/com/google/jspecify/nullness/NullSpecChecker.java
index 4d490c8..54d6139 100644
--- a/src/main/java/com/google/jspecify/nullness/NullSpecChecker.java
+++ b/src/main/java/com/google/jspecify/nullness/NullSpecChecker.java
@@ -69,6 +69,11 @@ public NavigableSet<String> getSuppressWarningsPrefixes() {
     return prefixes;
   }
 
+  @Override
+  protected String suppressWarningsString(String messageKey) {
+    return "nullness";
+  }
+
   @Override
   public void initChecker() {
     super.initChecker();