@@ -12,6 +12,8 @@
 import graphql.schema.GraphQLScalarType;
 import graphql.schema.GraphQLType;
 import graphql.schema.GraphQLUnionType;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -21,6 +23,7 @@
 import static java.lang.String.format;
 
 @PublicApi
+@NullMarked
 public class TypeMismatchError implements GraphQLError {
 
     private final String message;
@@ -65,7 +68,7 @@ public String getMessage() {
     }
 
     @Override
-    public List<SourceLocation> getLocations() {
+    public @Nullable List<SourceLocation> getLocations() {
         return null;
     }
 
 
@@ -11,7 +11,6 @@ import spock.lang.Specification
 class JSpecifyAnnotationsCheck extends Specification {
 
     private static final Set<String> JSPECIFY_EXEMPTION_LIST = [
-            "graphql.TypeMismatchError",
             "graphql.TypeResolutionEnvironment",
             "graphql.UnresolvedTypeError",
             "graphql.agent.result.ExecutionTrackingResult",