diff --git a/default.xml b/default.xml
index 14214b4..2306ab9 100644
--- a/default.xml
+++ b/default.xml
@@ -133,6 +133,7 @@
   <project path="external/eigen" name="platform/external/eigen" groups="pdk" />
   <project path="external/elfutils" name="platform/external/elfutils" groups="pdk" />
   <project path="external/emma" name="platform/external/emma" groups="pdk-cw-fs,pdk-fs" />
+  <project path="external/error_prone" name="platform/external/error_prone" groups="pdk" />
   <project path="external/esd" name="platform/external/esd" groups="pdk-cw-fs,pdk-fs" />
   <project path="external/expat" name="platform/external/expat" groups="pdk" />
   <project path="external/eyes-free" name="platform/external/eyes-free" groups="pdk-cw-fs,pdk-fs" />