diff --git a/ci/prepare.py b/ci/prepare.py
index 02203017a195883429a9b1e9ad544dace7b4ed99..1f684e424271f0117b30c3b43c0ae5789d34800b 100755
--- a/ci/prepare.py
+++ b/ci/prepare.py
@@ -47,9 +47,9 @@ def extract_cmake_package(artifacts, name):
 
 if __name__ == "__main__":
     if system() == "Windows":
-        job_stem = "package windows"
+        job_stem = "package: [windows]"
     elif system() == "Linux":
-        job_stem = "package centos"
+        job_stem = "package: [centos]"
     else:
         assert False