diff --git a/README.md b/README.md
index 9955592..4e24578 100644
--- a/README.md
+++ b/README.md
@@ -46,9 +46,11 @@ intake
 }
 ```
 
-Each key under `action` defines an action that can be taken for the source. A minimal `intake.json` must contain a `fetch` action with an `exe`. All other configs are optional.
+Each key under `action` defines an action that can be taken for the source. An action must contain `exe` and may contain `args`. A source must have a `fetch` action.
 
-The `fetch` action is executed by `intake update`. All other actions are executable with `intake action`. `intake crontab` will create a crontab entry for each source with a `cron` config defined. The value of `cron` is the crontab spec according to which the source should be updated.
+Each key under `env` defines an environment variable that will be set when actions are executed.
+
+If `cron` is present, it must define a crontab schedule. Intake will automatically create crontab entries to update each source according to its cron schedule.
 
 ## Interface for source programs
 
@@ -66,7 +68,7 @@ The `fetch` action is used to fetch the current state of the feed source. It rec
 
 An item must have a key under `action` with that action's name to support executing that action for that item. The value under that key may be any JSON structure used to manage the item-specific state.
 
-All encoding is done with UTF-8. If an item cannot be parsed or the exit code of the process is nonzero, Intake will consider the action to be a failure. No items or other feed changes will happen as a result of a failed action, except for changes to `state` done by the action process.
+All input and output is treated as UTF-8. If an item cannot be parsed or the exit code of the process is nonzero, Intake will consider the action to be a failure. No items or other feed changes will happen as a result of a failed action, except for changes to `state` done by the action process.
 
 ## Top-level item fields
 
diff --git a/demo/default.nix b/demo/default.nix
index c09dcd9..4539b20 100644
--- a/demo/default.nix
+++ b/demo/default.nix
@@ -67,19 +67,21 @@
 
   # Include some demo instructions
   environment.etc.issue.text = ''
+    ###
     # Welcome to the intake demo! Log in as `alice` with password `alpha` to begin.
-
+    #
     # Exit the VM with ctrl+a x, or switch to the qemu console with ctrl+a c and `quit`.
-
+    ###
   '';
   users.motd = ''
-
+    ###
     # To set a password for the web interface, run `intake passwd` and set a password.
-
+    #
     # Within this demo VM, the main intake entry point can be found at localhost:8080. This is also exposed on the host machine at localhost:5234. After you set a password, navigate to localhost:5234 on your host machine and log in to see the web interface.
-
-    # Try updating the currenttime source by running `intake update -s currenttime`. You should see a new item after refreshing the source's feed.
-
-    # The `echo` source demonstrates the use of `env` source configuration. Try changing the message in the web interface or via `intake edit -s echo`, then updating the source.
+    #
+    # Try updating the `echo` source by running `intake update -s echo`. You should see a new item after refreshing the source's feed. This source uses `env` source configuration, so use `intake edit -s echo` or the web interface to change the message, then update the source again.
+    #
+    # Updating a source will also trigger intake to update the user crontab. If you run `crontab -l`, you should see that the `currenttime` source has a crontab entry. You can change this source's cron schedule in the source config.
+    ###
   '';
 }
diff --git a/intake/app.py b/intake/app.py
index eabed54..1fe5069 100644
--- a/intake/app.py
+++ b/intake/app.py
@@ -19,6 +19,7 @@ from flask import (
 )
 
 from intake.core import intake_data_dir
+from intake.crontab import update_crontab_entries
 from intake.source import LocalSource, execute_action, Item
 
 # Globals
@@ -273,6 +274,7 @@ def source_edit(name):
         error_message, config = _parse_source_config(config_str)
         if not error_message:
             source.save_config(config)
+            update_crontab_entries(data_path)
             return redirect(url_for("root"))
 
     # For GET, load the config
diff --git a/intake/cli.py b/intake/cli.py
index 74f50bb..23bfa8e 100644
--- a/intake/cli.py
+++ b/intake/cli.py
@@ -82,6 +82,7 @@ def cmd_edit(cmd_args):
             return 0
 
         tmp_path.replace(source.source_path / "intake.json")
+        update_crontab_entries(data_path)
         break
 
     return 0
@@ -297,24 +298,6 @@ def cmd_passwd(cmd_args):
     return 0
 
 
-def cmd_crontab(cmd_args):
-    """Update cron with configured source cron entries."""
-    parser = argparse.ArgumentParser(
-        prog="intake crontab",
-        description=cmd_crontab.__doc__,
-    )
-    parser.add_argument(
-        "--data",
-        "-d",
-        help="Path to the intake data directory containing source directories",
-    )
-    args = parser.parse_args(cmd_args)
-
-    data_path: Path = Path(args.data) if args.data else intake_data_dir()
-    update_crontab_entries(data_path)
-    return 0
-
-
 def cmd_run(cmd_args):
     """Run the default Flask server."""
     parser = argparse.ArgumentParser(
diff --git a/module.nix b/module.nix
index 2bdb2df..33757d4 100644
--- a/module.nix
+++ b/module.nix
@@ -112,6 +112,8 @@ in {
     systemd.services =
     let
       runScript = userName: pkgs.writeShellScript "intake-run.sh" ''
+        # Add the setuid wrapper directory so `crontab` is accessible
+        export PATH="${config.security.wrapperDir}:$PATH"
         ${pythonEnv}/bin/intake run -d /home/${userName}/.local/share/intake --port ${toString userPort.${userName}}
       '';
       # systemd service definition for a single user, given `services.intake.users.userName` = `userCfg`