diff --git a/methods/chat/chat.postMessage.json b/methods/chat/chat.postMessage.json
index 236c1225..3d222ac7 100644
--- a/methods/chat/chat.postMessage.json
+++ b/methods/chat/chat.postMessage.json
@@ -149,6 +149,7 @@
     "team_access_not_granted": "The token used is not granted the specific workspace access required to complete this request.",
     "too_many_attachments": "Too many attachments were provided with this message. A maximum of 100 attachments are allowed on a message.",
     "too_many_contact_cards": "Too many contact_cards were provided with this message. A maximum of 10 contact cards are allowed on a message.",
+    "cannot_reply_to_message": "This message type cannot have thread replies.",
     "access_denied": "Access to a resource specified in the request is denied.",
     "account_inactive": "Authentication token is for a deleted user or workspace when using a bot token.",
     "deprecated_endpoint": "The endpoint has been deprecated.",