diff --git a/garlic/stages/trebuchet/default.nix b/garlic/stages/trebuchet/default.nix
index 7407b5a..68405f4 100644
--- a/garlic/stages/trebuchet/default.nix
+++ b/garlic/stages/trebuchet/default.nix
@@ -12,14 +12,23 @@
 
 stdenv.mkDerivation {
   name = "trebuchet";
+  phases = [ "installPhase" ];
   preferLocalBuild = true;
-  phases = [ "unpackPhase" "installPhase" ];
   dontPatchShebangs = true;
-  src = ./.;
-  inherit sshHost nixPrefix nixtools targetCluster program;
   installPhase = ''
-    substituteAllInPlace trebuchet
-    cp trebuchet $out
+    cat > $out <<EOF
+    #!/bin/sh -e
+    # Using the token @upload-to-mn@ we instruct the post-build hook to upload
+    # this script and it's closure to the MN4 cluster, so it can run there.
+    # Take a look at ${program}
+    # to see what is being executed.
+
+    nixtools=${nixPrefix}${nixtools}/bin
+    runexp=\$nixtools/${targetCluster}/runexp
+
+    >&2 echo "Launching \"\$runexp ${program}\" in MN4"
+    ssh ${sshHost} \$runexp ${program}
+    EOF
     chmod +x $out
   '';
 }
diff --git a/garlic/stages/trebuchet/trebuchet b/garlic/stages/trebuchet/trebuchet
deleted file mode 100755
index 6191d4a..0000000
--- a/garlic/stages/trebuchet/trebuchet
+++ /dev/null
@@ -1,14 +0,0 @@
-#!/bin/sh -ex
-# @upload-to-mn@
-
-# This program runs the current experiment in the ./result symlink in
-# MareNostrum. Requires that you define a "mn" host in the ssh config file
-# (usually in ~/.ssh/config).
-
-nixPrefix=@nixPrefix@
-nixtools=$nixPrefix@nixtools@/bin
-runexp=$nixtools/@targetCluster@/runexp
-
->&2 echo "Launching \"$runexp @program@\" in MN"
-
-ssh mn $runexp @program@