diff --git a/Makefile b/Makefile
index e725afc..d0168a8 100644
--- a/Makefile
+++ b/Makefile
@@ -60,15 +60,16 @@ check: node_modules/react-lite $(VM_IMAGE) test/common
 	TEST_AUDIT_NO_SELINUX=1 test/check-starter-kit
 
 # checkout Cockpit's bots/ directory for standard test VM images and API to launch them
+# must be from cockpit's master, as only that has current and existing images; but testvm.py API is stable
 bots:
 	git fetch --depth=1 https://github.com/cockpit-project/cockpit.git
 	git checkout --force FETCH_HEAD -- bots/
 	git reset bots
 
-# checkout Cockpit's test API
+# checkout Cockpit's test API; this has no API stability guarantee, so check out a stable tag
+# when you start a new project, use the latest relese, and update it from time to time
 test/common:
-	# when running in CI, update FETCH_HEAD to cockpit repo
-	if git remote | grep -qF test; then git fetch origin master; fi
+	git fetch --depth=1 https://github.com/cockpit-project/cockpit.git 163
 	git checkout --force FETCH_HEAD -- test/common
 	git reset test/common