diff --git a/src/tools/task/list-tasks.ts b/src/tools/task/list-tasks.ts
index 51989cd..b274600 100644
--- a/src/tools/task/list-tasks.ts
+++ b/src/tools/task/list-tasks.ts
@@ -153,10 +153,19 @@ function sortTasks(
                 break;
             }
             case "createdTime": {
-                // Use sortOrder as proxy for creation time
-                const orderA = a.sortOrder ?? 0;
-                const orderB = b.sortOrder ?? 0;
-                comparison = orderA - orderB;
+                // Extract timestamp from MongoDB ObjectID (first 8 hex chars)
+                // The sortOrder field values exceed JavaScript's safe integer range (2^53),
+                // causing precision loss during arithmetic operations.
+                // ObjectID's first 8 hex characters represent a Unix timestamp.
+                const getTimestampFromId = (id: string | undefined): number => {
+                    if (typeof id === 'string' && id.length >= 8) {
+                        return parseInt(id.substring(0, 8), 16);
+                    }
+                    return 0;
+                };
+                const timeA = getTimestampFromId(a.id);
+                const timeB = getTimestampFromId(b.id);
+                comparison = timeA - timeB;
                 break;
             }
         }