diff --git a/third_party/lisp/cl-date-time-parser.nix b/third_party/lisp/cl-date-time-parser.nix
index e53cb2dfc..bc847531e 100644
--- a/third_party/lisp/cl-date-time-parser.nix
+++ b/third_party/lisp/cl-date-time-parser.nix
@@ -4,10 +4,7 @@ depot.nix.buildLisp.library {
   name = "cl-date-time-parser";
 
   srcs = [
-    (pkgs.fetchurl {
-      url = "https://raw.githubusercontent.com/tkych/cl-date-time-parser/00d6fc70b599f460fdf13cf0cf7e6bf843312410/date-time-parser.lisp";
-      sha256 = "0zrkv1q3sx5ksijxhw45ixf1hy5b9biii6i6v41h12q6pbkfqz69";
-    })
+    "${pkgs.srcOnly pkgs.sbcl.pkgs.cl-date-time-parser}/date-time-parser.lisp"
   ];
 
   deps = [