--- a/src/lib/ai/claude/Ai_chat.luan	Sun Aug 10 11:29:02 2025 +0900
+++ b/src/lib/ai/claude/Ai_chat.luan	Mon Aug 11 07:58:32 2025 +0900
@@ -93,8 +93,12 @@
 		}
 		fn = function(input)
 			local Chat = require "site:/lib/Chat.luan"
+			local User = require "site:/lib/User.luan"
 			local thread_id = input.thread_id or error()
 			local chat = Chat.get_by_id(thread_id) or error
+			local user = User.current_user()
+			local is_owner = user ~= nil and user.id == chat.user_id
+			is_owner or not chat.is_private or error "private"
 			return chat.ai_thread or error()
 		end
 	}