diff --git a/components/zip321/proptest-regressions/lib.txt b/components/zip321/proptest-regressions/lib.txt
new file mode 100644
index 0000000000..cc91963dcd
--- /dev/null
+++ b/components/zip321/proptest-regressions/lib.txt
@@ -0,0 +1,7 @@
+# Seeds for failure cases proptest has generated in the past. It is
+# automatically read and these particular cases re-run before any
+# novel cases are generated.
+#
+# It is recommended to check this file in to source control so that
+# everyone who runs the test benefits from these saved cases.
+cc d4177f96a91940febe8e8b1dce6d71f6be3177305057a0057a72b3086eea11eb