Update OpenAPI schemas

Author: github-actions

core-api/core-api.json

@@ -2181,7 +2181,7 @@
             "properties": {
               "thread_ref": {
                 "type": "string",
-                "description": "Reference which will be used to thread messages. If  omitted, Front threads by sender instead"
+                "description": "Reference which will be used to thread messages. If omitted, Front threads by sender instead. This reference is unique to custom channels. If you supply a reference generated by another endpoint, the message will not thread into the same conversation."
               },
               "headers": {
                 "type": "object",
@@ -2542,7 +2542,7 @@
             "properties": {
               "thread_ref": {
                 "type": "string",
-                "description": "Reference which will be used to thread messages. If  omitted, Front threads by sender instead"
+                "description": "Reference which will be used to thread messages. If omitted, Front threads by sender instead. This reference is unique to importing historical messages. If you supply a reference generated by another endpoint, the message will not thread into the same conversation."
               },
               "is_inbound": {
                 "type": "boolean",
@@ -9180,7 +9180,7 @@
       "post": {
         "summary": "Import message",
         "operationId": "import-inbox-message",
-        "description": "Import a new message in an inbox.",
+        "description": "Import a new message in an inbox. **Only use this endpoint to import historical, non-active conversations**. Do not use it to create messages for new conversations.",
         "tags": [
           "Messages"
         ],