The European External Action Service is not technically speaking an official institution of the EU. The role of the EEAS is to serve the EU High Representative for Foreign Affairs and Security Policy, currently Federica Mogherini. The EEAS is in a sense the foreign service of the EU, but it shares a number of the roles of representing Europe on the international stage with the European Commission.
Most of the staff in EU delegations (that are the embassies of the EU) are EEAS staff and the EEAS is responsible for diplomatic representation of the EU and as such chairs formal summits with other countries.
The EEAS is the main overarching coordinating organisation of EU external relations. It is not responsible directly for all aspects of international action (i.e. trade for example is managed by DG TRADE) but it is responsible for overall coordination and representation – joining up and trying to make more coherent the EU’s different foreign policy tools.
The High Representative for Foreign Affairs and Security Policy
While the analogy is not perfect, the High Representative is in effect the Foreign Minister of the EU.
However, the post of High Representative is a difficult position to hold.
On the one hand, the “HRVP” (so called because of the dual role of High Representative and Vice President of the Commission) occupies a challenging place between being the representative of the member states on matters of EU foreign Policy and also having to coordinate EU external relations via the EEAS alongside the Commission.
They are a Commission Vice-President and thus part of the supranational EU Commission that is independent of member states and, at the same time, also representative for the EU member states (very much an intergovernmental position). Does this mean they lead the member states from their supranational Vice-President position, or follow them from their role as their High Representative?
Read this article for a (sympathetic) view of challenges faced by the former HRVP, Catherine Ashton.