diff --git a/demo/alice/currenttime/intake.json b/demo/alice/currenttime/intake.json
index c93b584..40b0a0c 100644
--- a/demo/alice/currenttime/intake.json
+++ b/demo/alice/currenttime/intake.json
@@ -1,11 +1,8 @@
 {
   "action": {
     "fetch": {
-      "exe": "sh",
-      "args": [
-        "-c",
-        "echo {\\\"id\\\": \\\"$(date +%Y-%m-%d-%H-%M)\\\"}"
-      ]
+      "exe": "currenttime.sh",
+      "args": []
     }
   }
 }
diff --git a/demo/alice/echo/intake.json b/demo/alice/echo/intake.json
new file mode 100644
index 0000000..dfe0dc7
--- /dev/null
+++ b/demo/alice/echo/intake.json
@@ -0,0 +1,11 @@
+{
+  "action": {
+    "fetch": {
+      "exe": "echo.py",
+      "args": []
+    }
+  },
+  "env": {
+    "MESSAGE": "Hello, Alice!"
+  }
+}
diff --git a/demo/bob/echo/intake.json b/demo/bob/echo/intake.json
new file mode 100644
index 0000000..8f41ac2
--- /dev/null
+++ b/demo/bob/echo/intake.json
@@ -0,0 +1,11 @@
+{
+  "action": {
+    "fetch": {
+      "exe": "echo.py",
+      "args": []
+    }
+  },
+  "env": {
+    "MESSAGE": "Hello, Bob!"
+  }
+}
diff --git a/demo/default.nix b/demo/default.nix
index d46ebe0..1f842db 100644
--- a/demo/default.nix
+++ b/demo/default.nix
@@ -40,19 +40,22 @@ flake: { pkgs, ... }:
     extraMounts = {
       "/mnt/alice" = ./alice;
       "/mnt/bob" = ./bob;
+      "/mnt/sources" = ./sources;
     };
   };
 
   # Create an activation script that copies and chowns the demo content
+  # chmod 777 because the users may not exist when the activation script runs
   system.activationScripts.demoSetup = ''
     ${pkgs.coreutils}/bin/mkdir -p /home/alice/.local/share/intake
     ${pkgs.coreutils}/bin/cp -r /mnt/alice/* /home/alice/.local/share/intake/
-    ${pkgs.coreutils}/bin/chgrp -R users /home/alice
-    ${pkgs.coreutils}/bin/chmod -R 775 /home/alice/.local
+    ${pkgs.coreutils}/bin/chmod -R 777 /home/alice/.local
 
     ${pkgs.coreutils}/bin/mkdir -p /home/bob/.local/share/intake
     ${pkgs.coreutils}/bin/cp -r /mnt/bob/* /home/bob/.local/share/intake/
-    ${pkgs.coreutils}/bin/chgrp -R users /home/bob
-    ${pkgs.coreutils}/bin/chmod -R 775 /home/bob/.local
+    ${pkgs.coreutils}/bin/chmod -R 777 /home/bob/.local
   '';
+
+  # Put the demo sources on the global PATH
+  environment.variables.PATH = "/mnt/sources";
 }
diff --git a/demo/sources/currenttime.sh b/demo/sources/currenttime.sh
new file mode 100755
index 0000000..06a3366
--- /dev/null
+++ b/demo/sources/currenttime.sh
@@ -0,0 +1,2 @@
+#!/bin/bash
+echo {\"id\": \"$(date +%Y-%m-%d-%H-%M)\"}
diff --git a/demo/sources/echo.py b/demo/sources/echo.py
new file mode 100755
index 0000000..a30b021
--- /dev/null
+++ b/demo/sources/echo.py
@@ -0,0 +1,10 @@
+#!/usr/bin/env python
+
+import hashlib, json, os, sys
+
+echo = os.environ.get("MESSAGE", "Hello, world!")
+item = {
+    "id": hashlib.md5(echo.encode("utf8")).hexdigest(),
+    "title": echo,
+}
+print(json.dumps(item), file=sys.stdout)