diff --git a/tools/cd_hit_dup/cd_hit_dup.xml b/tools/cd_hit_dup/cd_hit_dup.xml
index 3aa3ee75..4afeb6ff 100644
--- a/tools/cd_hit_dup/cd_hit_dup.xml
+++ b/tools/cd_hit_dup/cd_hit_dup.xml
@@ -2,6 +2,9 @@
     <description>
         remove duplicates and detect chimaeras in sequencing reads
     </description>
+    <xrefs>
+        <xref type="bio.tools">cd_hit_dup</xref>
+    </xrefs>
     <requirements>
         <requirement type="package" version="0.5-2012-03-07-fix-dan-gh-0.0.1">cd-hit-auxtools</requirement>
     </requirements>
@@ -122,4 +125,4 @@ cd-hit-dup provides a number of options to tune how the duplicates are removed::
     <citations>
         <citation type="doi">10.1093/bioinformatics/bts565</citation>
     </citations>
-</tool>
\ No newline at end of file
+</tool>