diff --git a/lib/livebook/session.ex b/lib/livebook/session.ex
index 6055d36ed..281e68e9d 100644
--- a/lib/livebook/session.ex
+++ b/lib/livebook/session.ex
@@ -156,7 +156,7 @@ defmodule Livebook.Session do
 
         * `{:dir, dir}` - a directory file
 
-        * `{:url, url} - a base url to the files directory (with `/` suffix)
+        * `{:url, url}` - a base url to the files directory (with `/` suffix)
 
         * `{:inline, contents_map}` - a map with file names pointing to their
           binary contents