To prevent a long link:
- Just link a word or phrase:
- Select text, hit chain icon in composer, complete the form OR
- DONT select text, hit chain icon in composer and fill in the form
- But usually a link will onebox unless the target is somehow a badly run website or blocks the onebox crawler from your site. You can prevent a big inbox by adding some additional characters to the same line, then you will just get linked words.
The exact formatting of the link depends on your theme.