Check if post is added manually or through wp_insert_post()

I have found a solution without adding any other metaboxes. I haven’t thought about it but the import function in my plugin uses a nonce so I just check if my nonce is set or not.

Here is my save_post_events function:

add_action( 'save_post_events', 'wse_327066_example', 10, 3);
function wse_327066_example( $post_id, $post, $update ) {
  if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE || $post->post_status == 'trash' || !current_user_can( 'edit_posts' ) || isset( $_POST['_import_nonce'] ) ) 
    return;

  # Now I can do whatever I want with posts saved from the admin edit screen... 
}