diff --git a/Special-links.md b/Special-links.md
index 1281338..521e57e 100644
--- a/Special-links.md
+++ b/Special-links.md
@@ -1,5 +1,5 @@
 # HTTP links:
-* https://t.me/bot?start=foo. Starts `@bot` with parameter `foo`.
+* https://t.me/bot?start=foo. Starts `@bot` with parameter `foo`. Note that the maximum length for the start command is 64 alphanumerical characters.
 * https://t.me/share/url?url=foo. Lets the user select a chat and have their input be `foo`.
 * https://t.me/c/chat_id/msg_id. Opens the chat with ID `chat_id` and highlights the message with ID `msg_id`. Note that the `msg_id` doesn't seem optional.