org-agenda-add-entry-text-descriptive-links

org-agenda-add-entry-text-descriptive-links is a variable defined in `org-agenda.el'.
Its value is

t

Documentation:
Non-nil means export org-links as descriptive links in agenda added text.
This variable applies to the text added to the agenda when
`org-agenda-add-entry-text-maxlines' is larger than 0.
When this variable nil, the URL will (also) be shown.

You can customize this variable.