diff --git a/garlic/exp/nbody/tampi.nix b/garlic/exp/nbody/tampi.nix
index c5fd69f..90bdcca 100644
--- a/garlic/exp/nbody/tampi.nix
+++ b/garlic/exp/nbody/tampi.nix
@@ -101,7 +101,7 @@ let
   isolate = {stage, conf, ...}: with conf; w.isolate {
     program = stageProgram stage;
     clusterName = "mn4";
-    inherit nixPrefix;
+    inherit stage nixPrefix;
   };
 
   extrae = {stage, conf, ...}: w.extrae {
@@ -200,7 +200,8 @@ let
   trebuchet = stage: w.trebuchet {
     program = stageProgram stage;
     nixPrefix = common.nixPrefix;
-    experiment = experiment;
+    #experiment = experiment;
+    inherit stage;
   };
 
   isolatedRun = stage: isolate {
diff --git a/garlic/stages/experiment.nix b/garlic/stages/experiment.nix
index a397fbc..0be2d8f 100644
--- a/garlic/stages/experiment.nix
+++ b/garlic/stages/experiment.nix
@@ -14,6 +14,12 @@ let
 
   unitsString = builtins.concatStringsSep "\n"
     (map (x: "${stageProgram x}") units);
+
+  desc = builtins.concatStringsSep "\n"
+  (map (x: ''
+    #    ${x}
+    ${x.desc}'') units);
+
 in
 stdenv.mkDerivation {
   name = "experiment";
@@ -21,11 +27,14 @@ stdenv.mkDerivation {
   preferLocalBuild = true;
   dontPatchShebangs = true;
   inherit units;
+  inherit desc;
 
   installPhase = ''
     cat > $out << EOF
     #!/bin/sh
 
+    ${desc}
+
     # This is an experiment formed by the following units:
     ${unitsString}
     EOF
diff --git a/garlic/stages/isolate/default.nix b/garlic/stages/isolate/default.nix
index 644d2c7..d3a7211 100644
--- a/garlic/stages/isolate/default.nix
+++ b/garlic/stages/isolate/default.nix
@@ -7,6 +7,7 @@
 
 {
   program
+, stage
 , nixPrefix
 , clusterName
 }:
@@ -23,6 +24,7 @@ stdenv.mkDerivation {
   dontPatchShebangs = true;
   programPath = "/bin/stage1";
   inherit program nixPrefix clusterName nixtools busybox;
+  desc = "#  $out\n" + (if builtins.hasAttr "desc" stage then stage.desc else "");
   out = "$out";
   installPhase = ''
 
diff --git a/garlic/stages/launcher/default.nix b/garlic/stages/launcher/default.nix
deleted file mode 100644
index aa019da..0000000
--- a/garlic/stages/launcher/default.nix
+++ /dev/null
@@ -1,35 +0,0 @@
-{
-  stdenv
-, nixPrefix ? ""
-}:
-
-units:
-
-with stdenv.lib;
-
-let
-
-  stageProgram = stage:
-    if stage ? programPath
-    then "${stage}${stage.programPath}" else "${stage}";
-
-  unitsString = builtins.concatStringsSep "\n"
-    (map (x: "${stageProgram x}") units);
-in
-stdenv.mkDerivation {
-  name = "experiment";
-  phases = [ "installPhase" ];
-  preferLocalBuild = true;
-  dontPatchShebangs = true;
-  inherit units;
-
-  installPhase = ''
-    cat > $out << EOF
-    #!/bin/sh
-
-    # This is an experiment formed by the following units:
-    ${unitsString}
-    EOF
-    chmod +x $out
-  '';
-}
diff --git a/garlic/stages/launcher/old.nix b/garlic/stages/launcher/old.nix
deleted file mode 100644
index 763bdb4..0000000
--- a/garlic/stages/launcher/old.nix
+++ /dev/null
@@ -1,50 +0,0 @@
-{
-  stdenv
-, nixPrefix ? ""
-}:
-
-apps: # Each app must be unique
-
-stdenv.mkDerivation {
-  name = "launcher";
-  preferLocalBuild = true;
-
-  buildInputs = [] ++ apps;
-  apps = apps;
-  phases = [ "unpackPhase" "patchPhase" "installPhase" ];
-  dontPatchShebangs = true;
-  programPath = "/bin/run";
-
-  src = ./.;
-
-  inherit nixPrefix;
-
-  patchPhase = ''
-    substituteAllInPlace run
-  '';
-
-  installPhase = ''
-    mkdir -p $out/apps
-    for j in $apps; do
-      target=$out/apps/$(basename $j)
-      if [ -e $target ]; then
-        echo "Duplicated app: $j"
-        echo
-        echo "Provided apps: "
-        printf "%s\n" $apps
-        echo
-        exit 1
-      fi
-      ln -s $j $target
-    done
-
-    mkdir -p $out/bin
-    install -m755 run $out/bin/run
-    chmod +x $out/bin/*
-
-    # Mark the launcher for upload
-    touch $out/.upload-to-mn
-    # And mark it as an experiment
-    touch $out/.experiment
-  '';
-}
diff --git a/garlic/stages/launcher/run b/garlic/stages/launcher/run
deleted file mode 100644
index 3c98c2c..0000000
--- a/garlic/stages/launcher/run
+++ /dev/null
@@ -1,20 +0,0 @@
-#!/bin/sh -ex
-
->&2 echo "Running launcher"
-
-if [ ! -e "/nix" ]; then
-  >&2 echo "missing /nix"
-  exit 1
-fi
-
-if [ -z "$GARLIC_OUT" ]; then
-  >&2 echo "GARLIC_OUT is not set"
-  exit 1
-fi
-
-mkdir -p "$GARLIC_OUT"
-cd "$GARLIC_OUT"
-
-for j in @out@/apps/*; do
-  $j/bin/run
-done
diff --git a/garlic/stages/trebuchet.nix b/garlic/stages/trebuchet.nix
new file mode 100644
index 0000000..85e6b05
--- /dev/null
+++ b/garlic/stages/trebuchet.nix
@@ -0,0 +1,38 @@
+{
+  stdenv
+, nixtools
+}:
+
+{
+  program
+, nixPrefix
+, sshHost ? "mn"
+, targetCluster ? "mn4"
+, stage
+}:
+
+stdenv.mkDerivation {
+  name = "trebuchet";
+  phases = [ "installPhase" ];
+  preferLocalBuild = true;
+  dontPatchShebangs = true;
+  installPhase = ''
+    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.
+
+    #  $out
+    ${stage.desc}
+
+    nixtools=${nixPrefix}${nixtools}/bin
+    runexp=\$nixtools/${targetCluster}/runexp
+
+    >&2 echo "Launching \"\$runexp ${program}\" in MN4"
+    ssh ${sshHost} \$runexp ${program}
+    EOF
+    chmod +x $out
+  '';
+}
diff --git a/garlic/stages/trebuchet/default.nix b/garlic/stages/trebuchet/default.nix
deleted file mode 100644
index 6b397c7..0000000
--- a/garlic/stages/trebuchet/default.nix
+++ /dev/null
@@ -1,69 +0,0 @@
-{
-  stdenv
-, nixtools
-}:
-
-{
-  program
-, nixPrefix
-, sshHost ? "mn"
-, targetCluster ? "mn4"
-, experiment ? ""
-}:
-
-with stdenv.lib;
-
-let
-
-  dStages = foldr (stageFn: {conf, prevStage, stages}: {
-    conf = conf;
-    prevStage = stageFn {stage=prevStage; conf=conf;};
-    stages = [ (stageFn {stage=prevStage; conf=conf;}) ] ++ stages;
-  })
-    {conf=conf; stages=[]; prevStage=null;} stages;
-
-  stageProgram = stage:
-    if stage ? programPath
-    then "${stage}${stage.programPath}" else "${stage}";
-
-  linkStages = imap1 (i: s: {
-    num = "${toString i}";
-    name = "${toString i}-${baseNameOf s.name}";
-    stage = s;
-    programPath = stageProgram s;
-  }) dStages.stages;
-
-  units = builtins.concatStringsSep "\n"
-    (map (x: "#  ${x}") experiment.units);
-
-  firstStage = (x: x.programPath) (elemAt linkStages 0);
-in
-
-stdenv.mkDerivation {
-  name = "trebuchet";
-  phases = [ "installPhase" ];
-  preferLocalBuild = true;
-  dontPatchShebangs = true;
-  installPhase = ''
-    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.
-
-    # Executes the following experiment in MN4:
-    #  ${experiment}
-
-    # Which contains the following experiment units:
-    ${units}
-
-    nixtools=${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/unit.nix b/garlic/stages/unit.nix
index f20a4dd..fd834dd 100644
--- a/garlic/stages/unit.nix
+++ b/garlic/stages/unit.nix
@@ -30,8 +30,9 @@ let
     programPath = stageProgram s;
   }) dStages.stages;
 
-  stageList = builtins.concatStringsSep "\n"
-    (map (x: "#  ${x.stage}") linkStages);
+  desc = builtins.concatStringsSep "\n"
+    (map (x: "#      ${x.stage}") linkStages);
+
 
   firstStage = (x: x.programPath) (elemAt linkStages 0);
 in
@@ -39,12 +40,12 @@ stdenv.mkDerivation {
   name = "unit";
   preferLocalBuild = true;
   phases = [ "installPhase" ];
+  inherit desc;
   installPhase = ''
     cat > $out << EOF
     #!/bin/sh -e
 
-    # This script defines an experimental unit with the following stages:
-    ${stageList}
+    ${desc}
 
     # Set the experiment unit in the environment
     export GARLIC_UNIT=$(basename $out)
diff --git a/overlay.nix b/overlay.nix
index 72de9e2..b329277 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -207,10 +207,10 @@ let
         envRecord = callPackage ./garlic/stages/envRecord.nix { };
         valgrind  = callPackage ./garlic/stages/valgrind.nix { };
         isolate   = callPackage ./garlic/stages/isolate { };
-        trebuchet = callPackage ./garlic/stages/trebuchet { };
+        trebuchet = callPackage ./garlic/stages/trebuchet.nix { };
         strace    = callPackage ./garlic/stages/strace.nix { };
         unit      = callPackage ./garlic/stages/unit.nix { };
-        experiment= callPackage ./garlic/stages/experiment/default.nix { };
+        experiment= callPackage ./garlic/stages/experiment.nix { };
       };
 
       # Tests (move to bsc ?)