To use MediaWiki as a source of standard text templates please select 'System Properties' in the main menu and click 'New Property'.

Choose 'MediaWiki'  as the new property's name and edit the value as follows.

Set each value according to your MediaWiki configuration:

url=https://en.wikipedia.org/w/api.php
useragent=apiuser@mycompany.com
sentences=10

Choose a valid e-mail address for 'useragent'. This will be used in the request header according to the API guidelines of Wikipedia and MediaWiki.

For 'sentences' select the number of sentences to be extracted from the articles found to limit the lenght of content copied into your text.  MediaWiki will try to extract a suitable part of the content.