diff --git a/docs/reference/default-theme/config.md b/docs/reference/default-theme/config.md
index afe2cb04..a3df6237 100644
--- a/docs/reference/default-theme/config.md
+++ b/docs/reference/default-theme/config.md
@@ -331,7 +331,7 @@ export default {
   If you want to set different sidebar for different sub paths, you can set this option to a _sidebar object_:
 
   - The key should be the path prefix.
-  - The value should be a _sidebar array_.
+  - The value should be a _sidebar array_ or set to `'heading'` to automatically generate the sidebar from the page headers for just the corresponding path.
 
 - Example 1:
 
@@ -395,6 +395,7 @@ export default {
   theme: defaultTheme({
     // collapsible sidebar
     sidebar: {
+      '/guide/': 'heading',
       '/reference/': [
         {
           text: 'VuePress Reference',