diff --git a/CHANGES.txt b/CHANGES.txt
index bc80f3de21..9776d43f33 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,3 +1,12 @@
+New in master
+=============
+
+Features
+--------
+
+* New ``auto_command_starting`` signal when ``nikola auto`` is
+  starting
+
 New in v8.1.3
 =============
 
diff --git a/nikola/plugins/command/auto/__init__.py b/nikola/plugins/command/auto/__init__.py
index 9de5622866..cc089c59c3 100644
--- a/nikola/plugins/command/auto/__init__.py
+++ b/nikola/plugins/command/auto/__init__.py
@@ -37,6 +37,7 @@
 import typing
 import webbrowser
 
+import blinker
 import pkg_resources
 
 from nikola.plugin_categories import Command
@@ -149,6 +150,8 @@ def _execute(self, options, args):
         elif Observer is None:
             req_missing(['watchdog'], 'use the "auto" command')
 
+        blinker.signal('auto_command_starting').send(self.site)
+
         if sys.argv[0].endswith('__main__.py'):
             self.nikola_cmd = [sys.executable, '-m', 'nikola', 'build']
         else: