An EU official in a third country delegation must implement a new confidential document management system operating under the framework of the Common Foreign and Security Policy (CFSP) and the Common Security and Defence Policy (CSDP). The system must guarantee effective coordination with the foreign ministries of the Member States and the EU institutions, complying with the EU principles on a rules-based global order. Given that the structure of the European External Action Service (EEAS) is governed by the Treaty of Lisbon, what is the fundamental operational mechanism that allows the EEAS to ensure coherence in the EU's international action in this specific scenario?