diff --git a/README.md b/README.md
index c3eb095..c8f188e 100644
--- a/README.md
+++ b/README.md
@@ -125,6 +125,9 @@ var server = new Server({
 
     var allowed = (infoHash === 'aaa67059ed6bd08362da625b3ae77f6f4a075aaa')
     cb(allowed)
+
+    // In addition to returning a boolean (`true` for allowed, `false` for disallowed),
+    // you can return an `Error` object to disallow and provide a custom reason.
   })
 })