diff --git a/lib/default.nix b/lib/default.nix
index f2ea1c0..988c2a5 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -12,5 +12,5 @@ lib.makeExtensible (self: rec {
       date = mkDate (input.lastModifiedDate or "19700101");
       rev = input.shortRev or "dirty";
     in
-    "unstable-${date}_${rev}}";
+    "unstable-${date}_${rev}";
 })