Add warning about automatic OpenAPI endpoint generation (#1970)

* Update organize/navigation.mdx

* move for more info link higher

* use note

---------

Co-authored-by: mintlify[bot] <109931778+mintlify[bot]@users.noreply.github.com>
Co-authored-by: Ethan Palm <56270045+ethanpalm@users.noreply.github.com>

Author: mintlify[bot]

organize/navigation.mdx

@@ -399,6 +399,14 @@ Integrate OpenAPI specifications directly into your navigation structure to auto
 
 Set a default OpenAPI specification at any level of your navigation hierarchy. Child elements will inherit this specification unless they define their own specification.
 
+<Note>
+  When you add the `openapi` property to a navigation element (such as an anchor, tab, or group) without specifying any pages, Mintlify automatically generates pages for **all endpoints** defined in your OpenAPI specification.
+  
+  To control which endpoints appear, explicitly list the desired endpoints in a `pages` array.
+</Note>
+
+For more information about referencing OpenAPI endpoints in your docs, see the [OpenAPI setup](/api-playground/openapi-setup).
+
 ```json
 {
   "navigation": {
@@ -426,8 +434,6 @@ Set a default OpenAPI specification at any level of your navigation hierarchy. C
 }
 ```
 
-For more information about referencing OpenAPI endpoints in your docs, see the [OpenAPI setup](/api-playground/openapi-setup).
-
 ## Versions
 
 Partition your navigation into different versions. Versions are selectable from a dropdown menu.